Dissertations / Theses: 'UAVs photogrammetry'

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Gonzales, Jack Joseph. "Comparing UAV and Pole Photogrammetry for Monitoring Beach Erosion." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104997.

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Sandy beaches are vulnerable to extreme erosion during large storms, as well as gradual erosion processes over months and years. Without monitoring and adaptation strategies, erosion can put people, homes, and other infrastructure at risk. To effectively manage beach resources and respond to erosion hazards, coastal managers must have a reliable means of surveying the beach to monitor erosion and accretion. These elevation surveys typically incorporate traditional ground-based surveying methods or lidar surveys flown from large, fixed-wing aircraft. While both strategies are effective, advancements in photogrammetric technology offers a new solution for topographic surveying: Structure from Motion (SfM). Using a set of overlapping aerial photographs, the SfM workflow can generate accurate topographic surveys, and promises to provide a fast, inexpensive, and reliable method for routine beach surveying. Unmanned aerial vehicles (UAVs) are often successfully employed for SfM surveys but can be limited by poor weather ad government regulations, which can make flying difficult or impossible. To circumvent these limitations, a digital camera can be attached to a tall pole on a mobile platform to obtain aerial imagery, avoiding the restrictions of UAV flight. This thesis compares these two techniques of image acquisition for routine beach monitoring. Three surveys were conducted at monthly intervals on a beach on the central South Carolina coast, using both UAV and pole photogrammetry. While both methods use the same software and photogrammetric workflow, the UAV produced better results with far fewer processing artifacts compared to pole photogrammetry.
Master of Science
Beach environments are vulnerable to extreme erosion, especially in the face of sea level rise and large storms like hurricanes. Monitoring erosion is a crucial part of a coastal management strategy, to mitigate risk to coastal hazards like extreme erosion, storm surge, and flooding. Erosion monitoring usually involves repeated elevation surveys to determine how much sand is being lost from the beach, and where that sand is being eroded away. Within the past decade, Structure from Motion (SfM) photogrammetry, the process of deriving ground elevation maps from multiple overlapping aerial photographs, has become a common technique for repeated elevation surveys. Unmanned aerial vehicles (UAVs) are often used to gather aerial imagery for SfM elevation surveys but are limited by poor weather conditions and government flight regulations, both of which can prohibit flight. However, similar aerial photographs can be taken with a camera mounted atop a tall pole, which can be used in wider range of weather conditions and without government regulations, providing an alternative when UAV flight is not an option. This study compares these two platforms for routine beach erosion monitoring surveys, evaluating them based on performance, cost, and feasibility. The UAV system is found to be fast, affordable, and effective, while the pole photogrammetry system is heavily affected by the slow speed of surveying and processing errors that make it unusable without significant improvement.

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TEPPATI, LOSE' LORENZO. "Geomatics support to the metric documentation of the archaeological heritage. Tests and validations on the use of low-cost, rapid, image-based sensors and systems." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2735515.

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Hedqvist, Emma, and Daniel Jakobsson. "Uppdatering av nationella höjdmodellen över begränsade områden med hjälp av UAS." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22073.

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I det här examensarbetet undersöks möjligheten att använda UAS över begränsade områden när den nationella höjdmodellen skapad av Lantmäteriet ska uppdateras. Ämnet var ett förslag från Lantmäteriet och huvudsyftet var att testa om UAS kan användas som komplettering till traditionell flygfotografering. Det blir allt vanligare att använda UAS inom till exempel geomatiken, eftersom det är ett bra verktyg när ett snabbt och effektivt resultat krävs. Lantmäteriet använder flygburen laserskanning vid genereringen av nationella höjdmodellen och den uppdateras med traditionell flygfotografering. Andra aspekter som undersökts i detta examensarbete var vilken mätosäkerhet kan uppnås med UAS vid framställandet av en DHM, vilken skillnad i lägesosäkerhet finns mellan studiens punktmoln jämfört med nationella höjdmodellen, samt mot punktmolnet genererat från traditionell flygfotografering och den ekonomiska aspekten vid användning av UAS. Detta utfördes genom att samla in data med hjälp av UAS över Furuvik, Gävle. Flyghöjden var 88 m över ett område på ca 1 ha. Därefter skapades en höjdmodell som kontrollerades enligt den tekniska specifikationen SIS-TS 21144:2013. I examensarbetet jämfördes punktmolnet som genererades från flygfoton tagna med UAS mot nationella höjdmodellen. Osäkerheten för den genererade höjdmodellen vid användandet av UAS visade ett bra resultat i höjd med en standardosäkerhet på 0,015 m. Punktmolnet genererat från Lantmäteriets bildmatchning låg 0,315-0,392 m under studiens punktmoln medan punktmolnet från laserskanningen låg 0,014-0,155 m över. Resultatet visade att användning av UAS är väldigt kostnadseffektivt när den nationella höjdmodellen över begränsade områden ska uppdateras. Det rekommenderas därför för Lantmäteriet att använda UAS för detta ändamål. Det blir mer än väl godkänt resultat och kostnaden är liten med tanke på resultatet, d.v.s. en metod för att verkligen kunna ajourhålla nationella höjdmodellen och komplettera traditionell flygfotografering över begränsade områden. Med denna metod slipper de vänta på att den traditionella flygfotograferingen ska ske. Tekniken går hela tiden framåt och inom en snar framtid kommer även laserskanning kunna ske med UAS. Det skulle vara intressant att se resultat av den metoden. Intressant skulle även vara att se om det i framtiden går att utesluta flygsignalering och verkligen kunna använda direkt georeferering för att spara tid ute i fält.
In this thesis we are going to investigate possibility of using UAS, over small areas, for updating national elevation model produced by the National Land Survey of Sweden. The subject of the thesis was proposed by the National Land Survey of Sweden. One of the main objectives of the study was to test if UAS can be used as a complement to traditional aerial photo. The use of UAS has increased over the years within for example geomatics, because it is a great tool when quick and effective results are required. The National Land Survey of Sweden uses airborne laser scanning to generate the national elevation model. The elevation model is then updated by traditional aerial photogrammetry. Other objectives that have been investigated in this study are what uncertainty can be expected with UAS when generating a DEM, the differences in uncertainty between the point cloud generated in this study to the national height model and to the point cloud generated from the traditional photogrammetry and the economic aspects when using UAS. For this purpose data was collected by UAS in Furuvik, Gävle. The flight height was 88 m over the area of about 1 ha. Then a DEM was created and controlled according to the technical specification SIS-TS 21144:2013. In this thesis a comparison between the point cloud generated in this study and the national elevation model has been performed. Uncertainty of the produced DEM using UAS showed very good result in height with a standard deviation of 0.015 m. The point cloud generated from the traditional photogrammetry was 0.315-0.392 m below the point cloud generated in this study, while the point cloud from laser scanning was 0.014-0.155 m above. The results showed that using UAS are very cost-effective to update the national elevation model. It is advisable for the National Land Survey of Sweden to update the national height model over small areas with this method. There will be more than efficient and the costs are small considering the result. In other word this method is to recommend when updating the national elevation model and can be used as a complement to traditional photogrammetry within limited areas. With this method, they will not have to wait for the traditional aerial photography to take place. The technology is constantly moving forward and in the near future laser scanning with UAS will occur. It would be interesting to see the results of that method. It would also be interesting to see if it is possible to exclude the ground control points, and really be able to use direct georeferencing to save time in the field.

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Hedenström, Linus, and Sebastian Eriksson. "An investigation of detecting potholes with UAV LiDAR and UAV Photogrammetry." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-36836.

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Potholes are caused by erosion and as such always emerging on our roadnetwork. Potholes may not only cause great damages to vehicles, but can alsocause road accidents, which in the worst case are fatal. Today, the detection ofpotholes is usually based on citizen reports or ocular inspection by vehicle,where a loose description of the potholes properties and location can be given.Recent research has explored the possibility of aerial inspection of paved roadswith the new, cost effective, Structure-from-Motion (SfM) technique, whichcan produce 3D point clouds from photogrammetric data. SfM point cloudshave then been used in conjunction with processing algorithms toautomatically detect and extract potholes from paved surfaces. However, theresults have not been optimal for practical use. The purpose of this study is,therefore, to explore the possibility of using UAV LiDAR for potholedetection in paved roads as a better alternative to the currently popularStructure-from-Motion (SfM) technique. A LiDAR point cloud is derived by alaser scanner and may have several advantages over SfM, for instance, theinsensitivity to poor light conditions and modelling errors. This study is setout to answer how point clouds derived from UAV SfM and UAV LiDARcompare to each other regarding detecting potholes of different sizes, wheredetected potholes will be compared to ground truth data. An elevation check,consisting of 126 height control points along the paved road, will also be usedto evaluate the height accuracy in the clouds. Data collection is done with theUAV system mdLiDAR3000DL aaS containing a RIEGL miniVUX-1DLlaser scanner for LiDAR data and Sony RX1R II 42.4 megapixel camera forSfM data. The data for both methods are collected during the same flight. Theproposed method automatically detects and extracts potholes from a pavedsurface based on the vertical distance to local reference planes which representthe undamaged road surface. The point clouds are filtered in CloudComparebefore imported to TerraScan for detection and extraction of potholes. Theextraction results are then controlled by a set of terrestrial measurements bytotal station. The results show that potholes with a smaller width of at least16.5 cm and a depth of at least 2.7 cm can be detected and extracted frompoint clouds derived by UAV LiDAR at a flight altitude of 30 m. Theextracted potholes had a standard deviation of 1.40 cm in width and 6.7 mmin depth. Shadows on the road caused height anomalies in the point cloudproduced by Structure-from-Motion (SfM), which made pothole detectionimpossible with the proposed methodology.
Potthål skapas genom erosion i vägar och uppstår varje år i vägnätet. Skadornapåverkar inte bara fordonens skick, utan kan även vara orsaken till olyckorsom i vissa fall är dödliga. I dagsläget detekteras potthål genom ockulärt frånfordon av kommunala arbetare eller så rapporteras de in av medborgare via etjänst där en lös beskrivning kan ges angående potthålens egenskaper ochposition.På senare tid har studier utforskat möjligheterna för flygburen inspektion avasfalterade vägar med den nya, kostnadseffektiva, Structure-from-Motion(SfM) tekniken som kan producera 3D-punktmoln från fotogrammetrisk data.Punktmolnen som är framtagna genom denna metod har vidare använtstillsammans med bearbetningsalgoritmer för att detektion och extraktion avpotthål i asfalterade vägar. Dock har resultaten inte varit optimala för attmetoden ska fungera i praktiken. Syftet med den här studien är därför attutforska möjligheten för att använda UAV LiDAR som en bättre metod fördenna process. Punktmoln framtagna genom LiDAR-teknik, mer känt somlaserskanning, kan ha ett flertal potentiella fördelar över SfM som okänslighetmot modelleringsfel och dåliga ljusförhållanden.Denna studie ger svar på hur punktmoln framtagna genom UAV LiDAR ochUAV SfM förhåller sig till varandra när det gäller detektion av potthål i olikastorlekar från asfalterade vägar, där potthålens dimensioner kommer attjämföras mot markbundna kontrollmätningar. Vidare görs en höjdkontrollmot 126 höjdstöd i båda punktmolnen för att jämföra kvaliteten förhöjdmätningar på den asfalterade vägen genom respektive metod.Insamlingen av data gjordes samtidigt under samma flygning för bådametoderna. Drönaren som användes var Microdrones mdLiDAR3000DL aaSmed en RIEGL miniVUX-1DL laserskanner och en Sony RX1R II 42,4megapixelkamera monterad. Mjukvarorna som har använts för bearbetning ärCloudCompare för filtrering av brus med mera och TerraScan för självadetektions -och extraktionsprocessen.Resultatet visar att det är möjligt att extrahera potthål från LiDAR-baseradepunktmoln med en mindre bredd på minst 16,5 cm och ett djup på 2,7 cm.Standardavvikelsen för potthålens bredd är 1,4 cm och 6,7 mm i djup.Grupper av avvikande punkter skapades på vägen i det SfM-baseradepunktmolnen som en följd av ett modelleringsfel i skuggområden på vägen,vilket vidare gjorde detektion -och extraktionsprocessen omöjlig med denframtagna metoden.

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Maier, Kathrin. "Direct multispectral photogrammetry for UAV-based snow depth measurements." Thesis, KTH, Geoinformatik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254566.

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Due to the changing climate and inherent atypically occurring meteorological events in the Arctic regions, more accurate snow quality predictions are needed in order to support the Sámi reindeer herding communities in northern Sweden that struggle to adapt to the rapidly changing Arctic climate. Spatial snow depth distribution is a crucial parameter not only to assess snow quality but also for multiple environmental research and social land use purposes. This contrasts with the current availability of affordable and efficient snow monitoring methods to estimate such an extremely variable parameter in both space and time. In this thesis, a novel approach to determine spatial snow depth distribution in challenging alpine terrain is presented and tested during a field campaign performed in Tarfala, Sweden in April 2019. A multispectral camera capturing five spectral bands in wavelengths between 470 and 860 nanometers on board of a small Unmanned Aerial Vehicle is deployed to derive 3D snow surface models via photogrammetric image processing techniques. The main advantage over conventional photogrammetric surveys is the utilization of accurate RTK positioning technology that enables direct georeferencing of the images, and thus eliminates the need for ground control points and dangerous and time-consuming fieldwork. The continuous snow depth distribution is retrieved by differencing two digital surface models corresponding to the snow-free and snow-covered study areas. An extensive error assessment based on ground measurements is performed including an analysis of the impact of multispectral imagery. Uncertainties and non-transparencies due to a black-box environment in the photogrammetric processing are, however, present, but accounted for during the error source analysis. The results of this project demonstrate that the proposed methodology is capable of producing high-resolution 3D snow-covered surface models (< 7 cm/pixel) of alpine areas up to 8 hectares in a fast, reliable and cost-efficient way. The overall RMSE of the snow depth estimates is 7.5 cm for data acquired in ideal survey conditions. The proposed method furthermore assists in closing the scale gap between discrete point measurements and regional-scale remote sensing, and in complementing large-scale remote sensing data by providing an adequate validation source. As part of the Swedish cooperation project ’Snow4all’, the findings of this project are used to support and validate large-scale snow models for improved snow quality prediction in northern Sweden.
På grund av klimatförändringar och naturliga meteorologiska händelser i arktis behövs mer exakta snökvalitetsprognoser för att stödja samernas rensköttsamhällen i norra Sverige som har problem med att anpassa sig till det snabbt föränderliga arktiska klimatet. Rumslig snödjupsfördelning är en avgörande parameter för att inte bara bedöma snökvaliteten utan även för flera miljöforskning och sociala markanvändningsändamål. Detta står i motsats till den nuvarande tillgången till överkomliga och effektiva metoder för snöövervakning för att uppskatta sådan extremt varierande parameter i tid och rum. I detta arbete presenteras och testas en ny metod för att bestämma rumslig snödjupssdistribution i utmanande alpin terräng under en fältstudie som genomfördes i Tarfala i norra Sverige i april 2019. Via fotogrammetrisk bildbehandlingsteknik hämtades snöytemodeller i 3D med hjälp av en multispektral kamera monterad på en liten obemannad drönare. En viktig fördel, i jämförelse med konventionella fotogrammetriska undersökningar, är användningen av exakt RTK-positioneringsteknik som möjliggör direkt georeferencing och eliminerar behovet av markkontrollpunkter. Den kontinuerliga snödjupfördelningen hämtas genom att ytmodellerna delas upp i snöfria respektive snötäckta undersökningsområden. En omfattande felsökning som baseras på markmätningar utförs, inklusive en analys av effekten av multispektrala bilder. Resultaten från denna studie visar att den famtagna metoden kan producera högupplösta snötäckta höjdmodeller i 3D (< 7 cm/pixel) av alpina områden på upp till 8 hektar på ett snabbt, pålitligt och kostnadseffektivt sätt. Den övergripande RMSE för det beräknade snödjupet är 7,5 cm för data som förvärvats under idealiska undersökningsförhållanden. Som ett led i det svenska projektet “Snow4all” används resultaten från projektet för att förbättra och validera storskaliga snömodeller för att bättre förutse snökvaliteten i norra Sverige.

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Nevins, Robert Pardy. "Georeferencing Unmanned Aerial Systems Imagery via Registration with Geobrowser Reference Imagery." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500378454106286.

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De, Lama Blasco Violeta. "Precision Analysis of Photogrammetric Data Collection Using UAV." Thesis, KTH, Geodesi och satellitpositionering, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209260.

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Lindström, Simon. "Utveckling av metoder för att säkerställa kvaliteten på höjddata insamlad med UAV : Fastställande av tillvägagångssätt vid luftburen datainsamling." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-84722.

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Företaget Team Exact levererar mätningstekniska tjänster, där den främsta verksamheten är riktad mot byggnads- och markindustrin. Företaget använder UAS och levererar tjänster till kunder med ortofoto och DEM som kan användas till kartläggning, volymberäkningar och planering. Team Exact använder konsultföretagets SkyMap’s webbaserade plattform i fotogrammetrisk bearbetning av UAV genererade flygbilder. DEM behöver uppnå HMK-standardnivå 3 för att användas som underlag till bygghandlingar. För att uppnå HMK-standardnivå 3 så krävs det en lägesosäkerhet på 0,02–0,05 m/ 0,03–0,07 m (plan/höjd). Team Exact uppnår god lägesosäkerhet i plan men har varierande resultat i höjdåtergivningen. Studien har således en målsättning att hitta metoder för att säkerställa höjden inom ett studieområde med varierande topografi, terräng och markytor. Faktorer som ska undersökas är markstödspunkter, RTK-data, flygstråk, kamerainställningar och tänkvärda åtgärder i skiftande topografi samt att se tendenser hur höjdåtergivningen varierar på olika markytor. Ett stomnät etablerades över studieområdet med tre fastställda koordinatsatta stompunkter, punkterna var inmätta med statisk NRTK mätning under 1 minut. Nätet jämnades ut med totalstation och därefter blev kontrollpunkter, profiler, ytor och markstödspunkter inmätta. Studien utredde lägesosäkerheten med 0, 5, 9 och 12 markstödspunkter. Den UAV som användes i studien är försedd med en RTK-modul och förväntades därav tillhandahålla positioneringsdata som var av värde att utreda. Markstödspunkternas utplacering planerades med fyra konstanta i studieområdets yttrehörn och en femte konstant på studieområdets högsta höjd. Resterande punkter placerades ut i en jämnfördelning över områdets toppar och dalar. Flygmetoderna som utvärderades var förankrade i tidigare studier. Gemensamma inställningar över samtliga metoder var studieområdets avgränsning, en flyghöjd på 40 m samt flyghastigheten på 3 m/s. Resterande var flytande parametrar som var av värde att utreda. Studien justerade parametrarna gällande flygstråk, övertäckning, kameravinkel och kamerainställningar. Totalt blev det tre flygmetoder där de fyra olika markstödskombinationerna undersöktes vilket gav 12 processer att utvärdera. Utvärderingen utfördes mot 77 kontrollpunkter där RMSE-värde för höjd och plan undersöktes. Kontrollpunkterna var jämnt fördelade över ytan och marktyperna. En ytterligare analys utfördes med volymberäkningar mellan referens terrängmodeller och de genererade terrängmodellerna. Flygmetod 3 gav bästa resultat där fotogrammetriinställningen Double Grid användes och överlappningen var 80/60 % samt att kameran tiltades till -70°. Sensorkänsligheten var inställd på ISO100, bländaren ett öppningsvärde f/5 och slutartiden var inställd på 1/500s. Studiens resultat visar att flygmetod 3 som blockutjämnats med 12 markstödspunkter genererade bästa resultat på en lägesosäkerhet i plan på 0,015 m samt 0,035 m i höjd.
The company Team Exact delivers measurement technical services, and the main business is aimed at the construction and land industry. The company uses UAS and offers services to customers and delivers products such as orthophotos and DEMs that can be used for mapping, volume calculations and planning. Team Exact uses the consulting company SkyMap’s web-based platform for photogrammetric processing of UAV-generated aerial images. DEM needs to achieve good positional uncertainty, to achieve HMK standard level 3, it is required that the basis for construction documents has a positional uncertainty of 0.02–0.05 m / 0.03–0.07 m (level / height). Team Exact achieves good positional uncertainty in horizontal coordinates but has varying results in height reproduction. The study thus aims to find methods to ensure the height within a study area with varying topography, terrain and ground surfaces. Factors to be investigated are ground control points, RTK data, flight paths, camera settings and conceivable measures in varying topography, as well as seeing trends in how the height representation differs on different ground surfaces. A coordinate network was established over the study area with three established coordinate reference points, the points were measured with static NRTK measurement 1 minute. The network was levelled with the total station and then control points, profiles, surfaces, and ground control points were measured. The study investigated the location uncertainty with 0, 5, 9 and 12 ground control points. The UAV used in the study is equipped with an RTK module and was therefore expected to provide positioning data that was worth investigating. The placement of the ground support points was planned with four constants in the outer corner of the study area and a fifth constant at the highest level of the study area. The remaining points were placed in an even distribution over the area’s peaks and valleys. The evaluated flight methods were rooted in previous studies. Common settings across all methods were the study area delimitation, 40 m flight altitude and the flight speed of 3 m/s. Remaining were floating parameters that were of value to investigate. The study adjusted the parameters regarding flight path, coverage, camera angle and camera settings. In total, there were three flight methods where the four different ground support combinations were examined, which gave 12 processes to evaluate. The evaluation was performed against 77 control points where the RMSE value for height and plane was examined. The control points were evenly distributed over the surface and soil types. A further analysis was performed with volume calculations between the reference terrain models and the generated terrain models. Flight method 3 gave the best results where the photogrammetry setting Double Grid was used and the overlap was 80/60 % and the camera was tilted to -70 °. The sensor sensitivity was set to ISO100, the shutter had an aperture value of f/5 and the shutter speed was set to 1/500s. The results of the study indicate that flight method 3, which was levelled with 12 ground support points, generated the best results on a positional uncertainty in horizontal coordinates of 0,015 m and 0,035 m in height.

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Woodget, Amy. "Quantifying physical river habitat parametres using hyperspatial resolution UAS imagery and SfM-photogrammetry." Thesis, University of Worcester, 2015. http://eprints.worc.ac.uk/3830/.

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Shahbazi, Mozhdeh. "On precise three-dimensional environment modeling via UAV-based photogrammetric systems." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9439.

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Abstract : Images acquired from unmanned aerial vehicles (UAVs) can provide data with unprecedented spatial and temporal resolution for three-dimensional (3D) modeling. Solutions developed for this purpose are mainly operating based on photogrammetry concepts, namely UAV-Photogrammetry Systems (UAV-PS). Such systems are used in applications where both geospatial and visual information of the environment is required. These applications include, but are not limited to, natural resource management such as precision agriculture, military and police-related services such as traffic-law enforcement, precision engineering such as infrastructure inspection, and health services such as epidemic emergency management. UAV-photogrammetry systems can be differentiated based on their spatial characteristics in terms of accuracy and resolution. That is some applications, such as precision engineering, require high-resolution and high-accuracy information of the environment (e.g. 3D modeling with less than one centimeter accuracy and resolution). In other applications, lower levels of accuracy might be sufficient, (e.g. wildlife management needing few decimeters of resolution). However, even in those applications, the specific characteristics of UAV-PSs should be well considered in the steps of both system development and application in order to yield satisfying results. In this regard, this thesis presents a comprehensive review of the applications of unmanned aerial imagery, where the objective was to determine the challenges that remote-sensing applications of UAV systems currently face. This review also allowed recognizing the specific characteristics and requirements of UAV-PSs, which are mostly ignored or not thoroughly assessed in recent studies. Accordingly, the focus of the first part of this thesis is on exploring the methodological and experimental aspects of implementing a UAV-PS. The developed system was extensively evaluated for precise modeling of an open-pit gravel mine and performing volumetric-change measurements. This application was selected for two main reasons. Firstly, this case study provided a challenging environment for 3D modeling, in terms of scale changes, terrain relief variations as well as structure and texture diversities. Secondly, open-pit-mine monitoring demands high levels of accuracy, which justifies our efforts to improve the developed UAV-PS to its maximum capacities. The hardware of the system consisted of an electric-powered helicopter, a high-resolution digital camera, and an inertial navigation system. The software of the system included the in-house programs specifically designed for camera calibration, platform calibration, system integration, onboard data acquisition, flight planning and ground control point (GCP) detection. The detailed features of the system are discussed in the thesis, and solutions are proposed in order to enhance the system and its photogrammetric outputs. The accuracy of the results was evaluated under various mapping conditions, including direct georeferencing and indirect georeferencing with different numbers, distributions and types of ground control points. Additionally, the effects of imaging configuration and network stability on modeling accuracy were assessed. The second part of this thesis concentrates on improving the techniques of sparse and dense reconstruction. The proposed solutions are alternatives to traditional aerial photogrammetry techniques, properly adapted to specific characteristics of unmanned, low-altitude imagery. Firstly, a method was developed for robust sparse matching and epipolar-geometry estimation. The main achievement of this method was its capacity to handle a very high percentage of outliers (errors among corresponding points) with remarkable computational efficiency (compared to the state-of-the-art techniques). Secondly, a block bundle adjustment (BBA) strategy was proposed based on the integration of intrinsic camera calibration parameters as pseudo-observations to Gauss-Helmert model. The principal advantage of this strategy was controlling the adverse effect of unstable imaging networks and noisy image observations on the accuracy of self-calibration. The sparse implementation of this strategy was also performed, which allowed its application to data sets containing a lot of tie points. Finally, the concepts of intrinsic curves were revisited for dense stereo matching. The proposed technique could achieve a high level of accuracy and efficiency by searching only through a small fraction of the whole disparity search space as well as internally handling occlusions and matching ambiguities. These photogrammetric solutions were extensively tested using synthetic data, close-range images and the images acquired from the gravel-pit mine. Achieving absolute 3D mapping accuracy of 11±7 mm illustrated the success of this system for high-precision modeling of the environment.
Résumé : Les images acquises à l’aide d’aéronefs sans pilote (ASP) permettent de produire des données de résolutions spatiales et temporelles uniques pour la modélisation tridimensionnelle (3D). Les solutions développées pour ce secteur d’activité sont principalement basées sur des concepts de photogrammétrie et peuvent être identifiées comme des systèmes photogrammétriques embarqués sur aéronefs sans pilote (SP-ASP). Ils sont utilisés dans plusieurs applications environnementales où l’information géospatiale et visuelle est essentielle. Ces applications incluent notamment la gestion des ressources naturelles (ex. : agriculture de précision), la sécurité publique et militaire (ex. : gestion du trafic), les services d’ingénierie (ex. : inspection de bâtiments) et les services de santé publique (ex. : épidémiologie et gestion des risques). Les SP-ASP peuvent être subdivisés en catégories selon les besoins en termes de précision et de résolution. En effet, dans certains cas, tel qu’en ingénierie, l’information sur l’environnement doit être de haute précision et de haute résolution (ex. : modélisation 3D avec une précision et une résolution inférieure à un centimètre). Pour d’autres applications, tel qu’en gestion de la faune sauvage, des niveaux de précision et de résolution moindres peut être suffisants (ex. : résolution de l’ordre de quelques décimètres). Cependant, même dans ce type d’applications les caractéristiques des SP-ASP devraient être prises en considération dans le développement des systèmes et dans leur utilisation, et ce, pour atteindre les résultats visés. À cet égard, cette thèse présente une revue exhaustive des applications de l’imagerie aérienne acquise par ASP et de déterminer les challenges les plus courants. Cette étude a également permis d’établir les caractéristiques et exigences spécifiques des SP-ASP qui sont généralement ignorées ou partiellement discutées dans les études récentes. En conséquence, la première partie de cette thèse traite des aspects méthodologiques et d’expérimentation de la mise en place d’un SP-ASP. Le système développé a été évalué pour la modélisation précise d’une gravière et utilisé pour réaliser des mesures de changement volumétrique. Cette application a été retenue pour deux raisons principales. Premièrement, ce type de milieu fournit un environnement difficile pour la modélisation, et ce, en termes de changement d’échelle, de changement de relief du terrain ainsi que la grande diversité de structures et de textures. Deuxièment, le suivi de mines à ciel ouvert exige un niveau de précision élevé, ce qui justifie les efforts déployés pour mettre au point un SP-ASP de haute précision. Les composantes matérielles du système consistent en un ASP à propulsion électrique de type hélicoptère, d’une caméra numérique à haute résolution ainsi qu’une station inertielle. La composante logicielle est composée de plusieurs programmes développés particulièrement pour calibrer la caméra et la plateforme, intégrer les systèmes, enregistrer les données, planifier les paramètres de vol et détecter automatiquement les points de contrôle au sol. Les détails complets du système sont abordés dans la thèse et des solutions sont proposées afin d’améliorer le système et la qualité des données photogrammétriques produites. La précision des résultats a été évaluée sous diverses conditions de cartographie, incluant le géoréférencement direct et indirect avec un nombre, une répartition et des types de points de contrôle variés. De plus, les effets de la configuration des images et la stabilité du réseau sur la précision de la modélisation ont été évalués. La deuxième partie de la thèse porte sur l’amélioration des techniques de reconstruction éparse et dense. Les solutions proposées sont des alternatives aux techniques de photogrammétrie aérienne traditionnelle et adaptée aux caractéristiques particulières de l’imagerie acquise à basse altitude par ASP. Tout d’abord, une méthode robuste de correspondance éparse et d’estimation de la géométrie épipolaire a été développée. L’élément clé de cette méthode est sa capacité à gérer le pourcentage très élevé des valeurs aberrantes (erreurs entre les points correspondants) avec une efficacité de calcul remarquable en comparaison avec les techniques usuelles. Ensuite, une stratégie d’ajustement de bloc basée sur l’intégration de pseudoobservations du modèle Gauss-Helmert a été proposée. Le principal avantage de cette stratégie consistait à contrôler les effets négatifs du réseau d’images instable et des images bruitées sur la précision de l’autocalibration. Une implémentation éparse de cette stratégie a aussi été réalisée, ce qui a permis de traiter des jeux de données contenant des millions de points de liaison. Finalement, les concepts de courbes intrinsèques ont été revisités pour l’appariement stéréo dense. La technique proposée pourrait atteindre un haut niveau de précision et d’efficacité en recherchant uniquement dans une petite portion de l’espace de recherche des disparités ainsi qu’en traitant les occlusions et les ambigüités d’appariement. Ces solutions photogrammétriques ont été largement testées à l’aide de données synthétiques, d’images à courte portée ainsi que celles acquises sur le site de la gravière. Le système a démontré sa capacité a modélisation dense de l’environnement avec une très haute exactitude en atteignant une précision 3D absolue de l’ordre de 11±7 mm.

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PASSONI, DANIELE. "Innovative Tools For Planning, Analysis, and Management of UAV Photogrammetric Surveys." Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/973446.

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The Unmanned Aerial System (UAV) is widely used in the photogrammetric surveys both for structures and small areas. The geomatics approach, for the several applications where the 3D modeling is required, focuses the attention on the metric quality of the final products of the survey. As widely known, the quality of results derives from the quality of images acquisition phase, which needs an accurate planning phase. Actually, the planning phase is typically managed using dedicated tools, adapted from the traditional aerial-photogrammetric flight plan. Unfortunately, UAV flight has features completely different from the traditional one, hence the use of UAV for photogrammetric applications today requires a growth in the planning knowledge. The basic idea of the present research work is to provide a tool for planning a photogrammetric survey with UAV, called “Unmanned Photogrammetric Office” (U.Ph.O.), that considers the morphology of the object, the effective visibility of its surface, in the respect of the metric precisions. The usual planning tools require the classical parameters of a photogrammetric planning: flight distance from the surface, images overlaps and geometric parameters of the camera. The created “Office suite” U.Ph.O. allows a realistic planning of a photogrammetric survey, requiring additionally an approximate knowledge of the Digital Surface Model (DSM) and the attitude parameters, potentially changing along the route. The planning products will be the realistic overlapping of the images, the Ground Sample Distance (GSD) and the precision on each pixel taking into account the real geometry. The different tested procedures, the solution proposed to estimates the realistic precisions in the particular case of UAV surveys and the obtained results, are described in this thesis work, with an overview on the recently development of UAV surveys and technologies related to them.

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Rojas, Ivan Yair. "Optimized Photogrammetric Network Design with Flight Path Planner for UAV-based Terrain Surveillance." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5573.

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This work demonstrates the use of genetic algorithms as a stochastic optimization technique for developing a camera network design and the flight path for photogrammetricapplications using Small Unmanned Aerial Vehicles. This study develops a Virtual Optimizer for Aerial Routes (VOAR) as a new photogrammetric mapping tool for acquisition of images to be used in 3D reconstruction. 3D point cloud models provide detailed information on infrastructure from places where human access may be difficult. This algorithm allows optimized flight paths to monitor infrastructure using GPS coordinates and optimized camera poses ensuring that the set of images captured is improved for 3D point cloud development. Combining optimization techniques, autonomous aircraft and computer vision methods is a new contribution that this work provides.This optimization framework is demonstrated in a real example that includes retrieving the coordinates of the analyzed area and generating autopilot coordinates to operate in fully autonomous mode. These results and their implications are discussed for future work and directions in making optical techniques competitive with aerial or ground based LiDAR systems.

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Bishop, Richard. "Applications of Close-Range Terrestrial 3D Photogrammetry to Improve Safety in Underground Stone Mines." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98920.

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The underground limestone mining industry is a small, but growing segment of the U.S. crushed stone industry. However, its fatality rate has been amongst the highest of the mining sector in recent years due to ground control issues related to ground collapses. It is therefore important to improve the engineering design, monitoring and visualization of ground control by utilizing new technologies that can help an underground limestone company maintain a safe and productive operation. Photogrammetry and laser scanning are remote sensing technologies that are useful tools for collecting three-dimensional spatial data with high levels of precision for many types of mining applications. Due to the reality of budget constraints for many underground stone mining operations, this research concentrates on photogrammetry as a more accessible technology for the average operation. Despite the challenging lighting conditions and size of underground limestone mines that has previous hindered photogrammetric surveys in these environments, over 13,000 photographic images were taken over a 3-year period in active mines to compile these models. This research summarizes that work and highlights the many applications of terrestrial close-range photogrammetry, including practical methodologies for implementing the techniques in working operations to better visualize hazards and pragmatic approaches for geotechnical analysis, improved engineering design and monitoring.
M.S.
The underground limestone mining industry is a small, but growing segment of the U.S. crushed stone industry. However, its fatality rate has been amongst the highest of the mining sector in recent years due to ground control issues related to ground collapses. It is therefore important to improve the engineering design, monitoring and visualization of ground control by utilizing new technologies that can help maintain safe and productive underground stone operations. Photogrammetry and laser scanning are remote sensing technologies that are useful tools for collecting three-dimensional spatial data with high levels of precision for many different mining applications. Due to the reality of budget constraints for many mining operations, this research concentrates on photogrammetry as a more accessible technology for the average operation, despite the challenging lighting conditions and expansive size of underground limestone mines that has previous hindered photogrammetric surveys in these environments. This research focuses on the applications of photogrammetry in underground stone mines and practical methodologies for implementing the techniques in working operations to better visualize hazards for improved engineering design and infrastructure management.

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Sieberth, Till. "Motion blur in digital images : analys, detection and correction of motion blur in photogrammetry." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/20212.

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Unmanned aerial vehicles (UAV) have become an interesting and active research topic for photogrammetry. Current research is based on images acquired by an UAV, which have a high ground resolution and good spectral and radiometrical resolution, due to the low flight altitudes combined with a high resolution camera. UAV image flights are also cost effective and have become attractive for many applications including, change detection in small scale areas. One of the main problems preventing full automation of data processing of UAV imagery is the degradation effect of blur caused by camera movement during image acquisition. This can be caused by the normal flight movement of the UAV as well as strong winds, turbulence or sudden operator inputs. This blur disturbs the visual analysis and interpretation of the data, causes errors and can degrade the accuracy in automatic photogrammetric processing algorithms. The detection and removal of these images is currently achieved manually, which is both time consuming and prone to error, particularly for large image-sets. To increase the quality of data processing an automated process is necessary, which must be both reliable and quick. This thesis proves the negative affect that blurred images have on photogrammetric processing. It shows that small amounts of blur do have serious impacts on target detection and that it slows down processing speed due to the requirement of human intervention. Larger blur can make an image completely unusable and needs to be excluded from processing. To exclude images out of large image datasets an algorithm was developed. The newly developed method makes it possible to detect blur caused by linear camera displacement. The method is based on human detection of blur. Humans detect blurred images best by comparing it to other images in order to establish whether an image is blurred or not. The developed algorithm simulates this procedure by creating an image for comparison using image processing. Creating internally a comparable image makes the method independent of additional images. However, the calculated blur value named SIEDS (saturation image edge difference standard-deviation) on its own does not provide an absolute number to judge if an image is blurred or not. To achieve a reliable judgement of image sharpness the SIEDS value has to be compared to other SIEDS values of the same dataset. This algorithm enables the exclusion of blurred images and subsequently allows photogrammetric processing without them. However, it is also possible to use deblurring techniques to restor blurred images. Deblurring of images is a widely researched topic and often based on the Wiener or Richardson-Lucy deconvolution, which require precise knowledge of both the blur path and extent. Even with knowledge about the blur kernel, the correction causes errors such as ringing, and the deblurred image appears muddy and not completely sharp. In the study reported in this paper, overlapping images are used to support the deblurring process. An algorithm based on the Fourier transformation is presented. This works well in flat areas, but the need for geometrically correct sharp images for deblurring may limit the application. Another method to enhance the image is the unsharp mask method, which improves images significantly and makes photogrammetric processing more successful. However, deblurring of images needs to focus on geometric correct deblurring to assure geometric correct measurements. Furthermore, a novel edge shifting approach was developed which aims to do geometrically correct deblurring. The idea of edge shifting appears to be promising but requires more advanced programming.

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Larsson, Alexander, and Olle Oscarsson. "Trädhöjdsbestämning med UAV-fotogrammetri och UAV-laserskanning : En jämförande studie för detektering av riskträd." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32699.

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UAV (Unmanned Aerial Vehicle) eller drönare används för insamling av geografisk data och fotografering av såväl företag, myndigheter och privatpersoner. Tekniken förenklar insamling av data över stora geografiska områden och kan utnyttjas för kartering, modellering och analysering som volymbestämning. Studien genomfördes med syftet att detektera trädhöjder ur punktmoln genererade med laserskanning och digital fotogrammetri från luften. Vidare undersöktes det vilken metod som gav det mest tillförlitliga resultatet samt om teknikerna var applicerbara för detektering av riskträd. Riskträd innebär i denna studie träd som utgör ett potentiellt hot mot viktig infrastruktur som till exempel kraftledningar. Numera sker datainsamlingen primärt via helikopter för identifiering av sådana träd. Genom att använda olika drönartekniker för datainsamlingen kan kostnaderna reduceras. Insamlingen av data genomfördes över ett glest barrskogsområde i Rörberg strax utanför Gävle. Laserdata samlades in med en LiDAR (Light Detection and Ranging)-sensor från YellowScan monterad på en Geodrone X4L Professional-drönare och de fotogrammetriska data med en drönare av typen DJI Phantom 4 RTK (Real Time Kinematic) med standardkamera. För bägge insamlingarna georefererades insamlade data direkt genom enkelstations-RTK för laserskanningen och med SWEPOS Nätverks-RTK för den fotogrammetriska flygningen. För att kontrollera kvaliteten av insamlade data mättes sex stycken kontrollprofiler in med totalstation i skogspartiet. Dessa jämfördes sedan mot de skapade punktmolnen. Medelavvikelsen och standardavvikelsen mellan LiDAR och kontrollprofilerna fastställdes till -0,038 m och 0,049 m. För fotogrammetrin och kontrollprofilerna bestämdes medelavvikelsen till +0,060 m och standardavvikelsen 0,090 m. Dessa värden jämfördes sedan mot kraven i SIS-TS 21144:2016. För att bestämma absoluta höjder mättes tio stycken träd in med totalstation. Trädens högsta och lägsta punkter koordinatbestämdes och utifrån subtraktion erhölls absoluta värden för vilka höjder från LiDAR- och fotogrammetriskt framställda trädhöjdsmodeller kom att jämföras mot. Jämförelsen mellan metoderna visade en medelavvikelse på -0,325 m för LiDAR och -0,928 m för fotogrammetrin. Slutsatsen av denna studie visar att LiDAR är den mest lämpade tekniken för detektering av trädhöjder och skapande av trädhöjdsmodeller. Detta baseras på erhållna höjdvärden, den digitala terrängmodellens kvalitet och den goda täckningen av punkter i plan och höjd för punktmolnet.
UAVs (Unmanned Aerial Vehicles) or drones are commonly used for collecting spatial data and aerial images by companies, state agencies and civilians. The UAV techniques makes collection of geodata easier for large areas and can be used for mapping, 3D modelling and other analyses, e.g. for volume determination. The aim of this study was to compare 3D point clouds generated from airborne laser scanning and digital photogrammetry for detecting heights of trees. It was also investigated which method produced the most reliable results and if these were applicable for detecting risk trees. The definition of risk trees in this study are trees that run the potential risk of damaging important infrastructure such as electric power transmission lines. Nowadays the collection of data is mainly conducted using helicopters for identifying the risk trees, but with UAV technologies costs can be significantly reduced. The collection of data was performed over a sparse coniferous forest area in Gävle, Sweden. Laser data was collected using a YellowScan LiDAR (Light Detection and Ranging) sensor mounted on a drone. For the photogrammetric data, a DJI Phantom 4 RTK (Real Time Kinematic) drone was used with its standard camera. Both techniques were directly georeferenced using Single station RTK and SWEPOS Network RTK respectively. To check the quality of the collected data, six control profiles were established using a total station. These measurements were then compared to the generated point clouds. Our results show that the mean deviation and standard deviation in height between LiDAR point clouds and the control profiles are -0,038 m and 0,049 m, respectively. The mean deviation and standard deviation for photogrammetric point clouds and control profiles are +0,060 m and 0.090 m, respectively. These values were then compared to the requirements in SIS-TS 21144:2016. To determine absolute tree heights, ten random trees were measured using a total station. The coordinates of the highest and lowest points of each tree were then subtracted to serve as absolute height values. The comparison of the two UAV methods showed mean height deviations of -0,325 m for LiDAR and -0,928 m for the photogrammetry. This study concludes that LiDAR is the most suitable technology of the two methods tested for detecting tree heights and creating canopy height models. This is based on the obtained height values, the quality of the digital terrain model and the good distribution of points in plane and height for the point cloud.

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Sköld, Olivia. "Analys av lägesosäkerheter hos fotogrammetriskt framställda DTM - en jämförelse mellan två programvaror." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32058.

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Idag blir användningen av drönare allt mer vanlig för dokumentation av markytor. Det är ett billigare alternativ för att dokumentera små och otillgängliga områden. Genom tekniken går det bland annat att framställa olika digitala modeller som representerar jordens yta. En sådan modell kan vara en terrängmodell (DTM) som är en modell av markytan exklusive vegetation, hus eller annat som befinner sig på marken. Modeller kan framställas genom flygdata såsom laserskannad (LiDAR-data) eller flygfotograferade data (flygbilder). För att framställa en digital modell från rådata används olika programvaror. Den här studien utvärderar två olika programvarors förmåga att framställa digitala terrängmodeller från flygbilder. Främst undersöks levererade osäkerheter och användarvänligheten i programmen. Referensdata som användes i denna studie tillhandahölls av Norconsult och samlades in vid ett projekt över Hammarbyhöjdsskogen i Stockholm, hösten 2018. Den data som erhölls från projektet till denna studie var flygbilder samt terrestra detaljmätningar. Programmen som studien utvärderar är UAS Master som både använder datorseende och fotogrammetriska metoder och SURE Aerial som använder datorseende. Genom studien visade det sig att fler än de ursprungliga programvarorna behövdes för att framställa de digitala terrängmodellerna och vidare jämföra dessa. En orsak var att UAS Master saknade förmågor att redigera och visa punktmoln i 3D-vy och vidare skapa en DTM. Detta resulterade i att använda Trimble Business Center för slutarbetet. En annan orsak var att SURE Aerial visade sig vara avsett för framställning av digitala ytmodeller (representation av den faktiska, synliga ytan). För att framställa en DTM av punktmolnet användes både Cloud Compare och Agisoft Photoscan (numera Metashape). Geo användes sedan för att ta ut höjdavvikelserna från modellen. Två slutsatser som kunde dras utifrån denna studie var: 1) trots de olika tillvägagångssätten erhölls snarlika resultat för marktypernas lägesosäkerheter för respektive programvara (asfalt: 0,039 m; grus: ca 0,040 m; gräs: ca 0,048 m), varpå alla blev godkända enligt HMK – Flygfotografering 2017; 2) SURE Aerial är ett enklare och snabbbare program men med UAS Master har man som användare bättre förståelse över processerna och erhåller bättre dokumentation.
Drones have become a more and more frequent tool to document the surface of the ground, especially in smaller areas that otherwise are too expensive to observe by other means. This technology makes it possible to create digital terrain models (DTM) that represents the surface of the ground excluding vegetation, houses or other objects on the ground. These models can be created by laser scanned data (LiDAR-data) or aerial photogrammetry (aerial photos). In order to create a digital model from raw data are various software needed. This study aims to test two software’s ability to create digital terrain models from UAS photos. The software were evaluated by the uncertainties of the models, as well as the user-friendliness of each software. All data used in this study was collected by Norconsult for another project in 2018 and consist of UAS photos and data from terrestrial measurements. The softwares used in this study for comparison are UAS Master (using both computer vision and photogrammetric methods) and SURE Aerial (using computer vision). It turned out that additional use of software were needed to create DTMs that were comparable. UAS Master could not show or edit point clouds in 3D, because of this the software Trimble Business Centre had to be used. This program was also used to obtain height deviations. SURE Aerial on the other hand turned out to only be able to create digital surface models (models of the visible ground). The software Cloud Compare and Agisoft Photoscan (nowadays Metashape) were therefore used to create the DTM from the point cloud. The height deviations from the ladder DTM were obtained from the software Geo. Two conclusions could be drawn from this study: 1) the uncertainties of the different surface types were similar in the software despite the different ways to create the DTMs (asphalt: 0.039 m; gravel: 0.040 m; grass: 0.048 m). All of which meet the requirements according to HMK – Flygfotografering 2017; 2) SURE Aerial is a lot easier and quicker to work with but UAS Master give the user a lot more feedback in the way of documentation throughout the different processes.

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Lanier, Prather Jonathan. "Stereovision Correction Using Modal Analysis." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31662.

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Presently, aerial photography remains a popular method for surveillance of landscapes, and its uses continually grow as it is used to monitor trends in areas such as plant distribution and urban construction. The use of computer vision, or more specifically stereo vision, is one common method of gathering this information. By mounting a stereo vision system on the wings of an unmanned aircraft it becomes very useful tool. This technique however, becomes less accurate as stereo vision baselines become longer, aircraft wing spans are increased, and aircraft wings become increasingly flexible. Typically, ideal stereo vision systems involve stationary cameras with parallel fields of view. For an operational aircraft with a stereo vision system installed, stationary cameras can not be expected because the aircraft will experience random atmospheric turbulence in the form of gusts that will excite the dominate frequencies of the aircraft. A method of stereo image rectification has been developed for cases where cameras that will be allowed to deflect on the wings of an fixed wing aircraft that is subjected to random excitation. The process begins by developing a dynamic model the estimates the behavior of a flexible stereo vision system and corrects images collected at maximum deflection. Testing of this method was performed on a flexible stereo vision system subjected to resonance excitation where a reduction in stereo vision distance error is shown. Successful demonstration of this ability is then repeated on a flying wing aircraft by the using a modal survey to understand its behavior. Finally, the flying wing aircraft is subjected to random excitation and a least square fit of the random excitation signal is used to determine points of maximum deflection suitable for stereo image rectification. Using the same techniques for image rectification in resonance excitation, significant reductions in stereo distance errors are shown.
Master of Science

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Wang, Xi. "ASSESSING THE APPLICATION OF THE UNMANNED AERIAL SYSTEMS (UAS) IN EARTHWORK VOLUME MEASUREMENT." UKnowledge, 2018. https://uknowledge.uky.edu/ce_etds/68.

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Earthwork operations are often one of the major cost items on infrastructure construction projects. Because earthwork is largely influenced by unstable construction conditions and organization plans, it becomes the emphasis and difficulties of the cost control in the construction process. Therefore, precise estimates of actual earthwork volumes are important for both owners and contractors alike to ensure appropriate payments are made. However, measuring work on site requires lots of time and labors because of various and irregular site conditions. Conventional measurement methods, such as planned quantities from the drawings or estimates from equipment activity, are rough estimates with significant opportunities for errors and safety concerns. Recently, unmanned aerial systems (UAS) have become popular for numerous surveying applications in civil engineering. They require less cost and time consumptions compared with traditionally manual methods. Also, they are able to perform photogrammetric data acquisition with equipped digital cameras in hazardous, complex or other conditions that may present high safety risks. However, UAS photogrammetry for research applications is still in its infancy, especially in construction management, and research conducted on UAS photogrammetry for earthwork volume estimation are very limited. Therefore, this research intends to investigate and validate the feasibility and efficiency of utilizing the UAS photogrammetry surveying technique to estimate earthwork volume. The research is conducted into three steps based on distinct case studies: firstly, adapting a basic analysis through a case study to preliminarily prove the effectiveness of the UAS photogrammetry method in earthwork volume measurement; also providing an analytical foundation for further utilizations; secondly, Quantitatively assessing the impact of flight parameters and environmental factors on the accuracy of UAS photogrammetry in earthwork volume measurement and identifying the most influential individual or combinations through observations and a statistical multiple regression analysis; at last, comparing volumes calculated by using the UAS platform and other two conventional methods which are Average-End-Area method and grid method in AutoCAD to further validate the feasibility of using the UAS technology in the process of earthwork volumes estimation. The results indicate that the UAS is an effective method for earthwork volume measurement. According to published standards, practice experience, and literature, the measurement errors are in an acceptable range when parameters are under control. In addition, the UAS demonstrates its advantages in balancing between the accuracy and efficiency compared with conventional earthwork volume measurement methods.

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Kašiár, Dominik. "Možnosti uplatnění UAV a podobných zařízení ve stavebnictví." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409889.

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The diploma thesis deals with the creation of a 3D model using laser scanning by unmanned aircraft (UAV). In the first part the author describes the history, legislation, the possibility of using unmanned aircraft and their dividing. The next section describes the process of creating a 3D model from data collection, using a drone to the actual modeling in Revit and subsequent use of the 3D model.

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20

Shintani, Christina. "Comparing Photogrammetric and Spectral Depth Techniques in Extracting Bathymetric Data from a Gravel-Bed River." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20517.

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Recent advances in through-water photogrammetry and optical imagery indicate that accurate, continuous bathymetric mapping may be possible in shallow, clear streams. This research directly compares the ability of through-water photogrammetry and spectral depth approaches to extract water depth for monitoring fish habitat. Imagery and cross sections were collected on a 140 meter reach of the Salmon River, Oregon, using an unmanned aerial vehicle (UAV) and rtk-GPS. Structure-from-Motion (SfM) software produced a digital elevation model (DEM) (1.5 cm) and orthophoto (0.37 cm). The photogrammetric approach of applying a site-specific refractive index provided the most accurate (mean error 0.009 m) and precise (standard deviation of error 0.17 m) bathymetric data (R2 = 0.67) over the spectral depth and the 1.34 refractive index approaches. This research provides a quantitative comparison between and within bathymetric mapping methods, and suggests that a site-specific refractive index may be appropriate for similar gravel-bed, relatively shallow, clear streams.

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Limongiello, Marco. "Vehículos aéreos no tripulados para el levantamiento y monitoreo de áreas arqueológicas." Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3003.

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2016 - 2017
The research focused on the analysis of the deviation that an aerofotogrammetric survey can produce with respect to the classic topographic surveys, by total station, GPS (Global Positioning System) or TLS (Terrestrial Laser Scanner), instruments with significantly higher sensitivity than the airborne system, and therefore affected by minor uncertainties. In the various applications, using topographic measurements from different systems and using the so-called GCP (Ground Control Point), the metric deviations between the geo-referenced photogrammetric model and the topographic support were calculated, evaluating the system’s metric potential in different configurations. Moreover, by a script, the reprojection errors were measured for each point of the cloud generated by the entire photogrammetric process; from statistical analysis of the reprojection error in the various case studies, the modalities for which the aerofotogrammetric survey has the smallest deviations have been evaluated. The elaborated case studies come essentially within the archaeological field, in which, in close contact with the various Sovraintendenze, the possible elaborations to be returned for an initial computerization of the survey were analyzed. The set of works produced and delivered to the various Sovraintendenze, represents the starting point for the conservation and preservation of the archaeological heritage, from which to obtain information for different areas of interest (degradation assessment, calculation of subsidence and / or deformations, etc…). The comparison with the classical topography is necessary for a metric comparison of the 3D model, from which all the elaborates will be derived (orthophotos, sections, level curves, etc.)...[edited by Author]
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Samani, Jakob. "UAS-noggrannhet i praktiken : En undersökning av dagens UAS-fotogrammetris noggrannhet." Thesis, Karlstads universitet, Institutionen för geografi, medier och kommunikation, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-31010.

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Sammanfattning Undersökningens syfte är att förstå hur noggrann UAS-fotogrammetrin i dagsläget (2013) är. Frågeställningarna som undersökningen utgick ifrån var: kan UAS-fotogrammetri i dagsläget ge precisa punkter med hjälp av att mäta in centrum av 1x1 meter utlagda plattor som kan ses i ortofoto?; Kan det ge snarlik noggrannhet med pixelstorleken? samt Kan UAS-tekniken idag användas för att producera pålitliga höjdmodeller? För att uppnå syftet har en undersökning utförts med jämförelse på koordinater insamlade med totalstation och insamlade med UAS-fotogrammetriska metoder. Resultatet visade att medelfelet var drygt 1 pixel på plana koordinater samt på koordinater i höjd. Pixlarnas storlek var mellan 4.7-9.3 cm. Största felkällan ser ut att vara upplösningen på bilderna, men tekniken utvecklas fort. UAS-fotogrammetrin lever väl upp till frågeställningarnas förväntningar.
Abstract The purpose of the study is to understand what the accuracy of UAS photogrammetry today (2013) is. The study was based on the following questions: Can UAS photogrammetry today give precise points, measuring the centre of 1x1 meter plywood boards viewed from an orthophoto?; Can it give similar accuracy as the size of the pixels? And can UAS technology today be used to produce elevation models of good quality? To investigate these questions, a study has been made to compare coordinates collected from a total station and UAS photogrammetric methods. The results show that the standard error is approximately 1 pixel on flat coordinates and 1 pixel on elevated coordinates. The pixel size was between 4.7 and 9.3 cm. The biggest source of error seems to be the resolution on the pictures, but the technology develops quickly. The UAS photogrammetry method definitely meets the expectations of the questions.

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Assefha, Sabina, and Matilda Sandell. "Evaluation of digital terrain models created in post processing software for UAS-data : Focused on point clouds created through block adjustment and dense image matching." Thesis, Högskolan i Gävle, Samhällsbyggnad, GIS, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26976.

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Lately Unmanned Aerial Systems (UAS) are used more frequently in surveying. With broader use comes higher demands on the uncertainty in such measurements. The post processing software is an important factor that affects the uncertainty in the finished product. Therefore it is vital to evaluate how results differentiate in different software and how parameters contribute. In UAS-photogrammetry images are acquired with an overlap which makes it possible to generate point clouds in photogrammetric software. These point clouds are often used to create Digital Terrain Models (DTM). The purpose of this study is to evaluate how the level of uncertainty differentiates when processing the same UAS-data through block adjustment and dense image matching in two different photogrammetric post processing software. The software used are UAS Master and Pix4D. The objective is also to investigate how the level of extraction in UAS Master and the setting for image scale in Pix4D affects the results when generating point clouds. Three terrain models were created in both software using the same set of data, changing only extraction level and image scale in UAS Master and Pix4D respectively. 26 control profiles were measured with network-RTK in the area of interest to calculate the root mean square (RMS) and mean deviation in order to verify and compare the uncertainty of the terrain models. The study shows that results vary when processing the same UAS-data in different software. The study also shows that the extraction level in UAS Master and the image scale in Pix4D impacts the results differently. In UAS Master the uncertainty decreases with higher extraction level when generating terrain models. A clear pattern regarding the image scale setting in Pix4D cannot be determined. Both software were able to produce elevation models with a RMS-value of around 0,03 m. The mean deviation in all models created in this study were below 0,02 m, which is the requirement for class 1 in the technical specification SIS-TS 21144:2016. However the mean deviation for the ground type gravel in the terrain model created in UAS Master at a low extraction level exceeds the demands for class 1. This indicates all but one of the created models fulfil the requirements for class 1, which is the class containing the highest requirements.
Obemannade flygfarkostsystem (eng. Unmanned Aerial Systems, UAS) används allt mer frekvent för datainsamling inom geodetisk mätning. I takt med att användningsområdena ökar ställs också högre krav på mätosäkerheten i dessa mätningar. De efterbearbetningsprogram som används är en faktor som påverkar mätosäkerheten i den slutgiltiga produkten. Det är därför viktigt att utvärdera hur olika programvaror påverkar slutresultatet och hur valda parametrar spelar in. I UAS-fotogrammetri tas bilder med övertäckning för att kunna generera punktmoln som i sin tur kan bearbetas till digitala terrängmodeller (DTM). Syftet med studien är att utvärdera hur mätosäkerheten skiljer sig när samma data bearbetas genom blockutjämning och tät bildmatchning i två olika programvaror. Programvarorna som används i studien är UAS Master och Pix4D. Målet är också att utreda hur vald extraktions nivå i UAS Master och vald bildskala i Pix4D påverkar resultatet vid generering av terrängmodeller. Tre terrängmodeller skapades i UAS Master med olika extraktionsnivåer och ytterligare tre skapades i Pix4D med olika bildskalor. 26 kontrollprofiler mättes in med nätverks-RTK i aktuellt område för beräkning av medelavvikelse och kvadratiskt medelvärde (RMS). Detta för att kunna verifiera och jämföra mätosäkerheten i modellerna. Studien visar att slutresultatet varierar när samma data bearbetas i olika programvaror. Studien visar också att vald extraktionsnivå i UAS Master och vald bildskala i Pix4D påverkar resultatet olika. I UAS Master minskar mätosäkerheten med ökad extraktionsnivå, i Pix4D är det svårare att se ett tydligt mönster. Båda programvaror kunde producera terrängmodeller med ett RMS-värde kring 0,03 m. Medelavvikelsen i samtliga modeller understiger 0,02 m, vilket är kravet för klass 1 från den tekniska specifikationen SIS-TS 21144:2016. Medelavvikelsen för marktypen grus i UAS Master i modellen med låg extraktionsnivå överskrider dock kraven för klass 1. Därmed uppnår alla förutom en av terrängmodellerna kraven för klass 1, vilket är den klass med högst ställda krav.

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Johnsson, Fredrik. "Objekthöjders betydelse för bildövertäckning vid UAV-fotografering." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-68607.

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Det finns ett fåtal studier som berör objekthöjders betydelse för bildövertäckning vid UAV-fotografering. Därför är det intressant att undersöka hur objekthöjder, bildövertäckningar, och flyghöjder påverkar varandra samt hur de gemensamt påverkar kvaliteten på data. Syfte är att undersöka hur bildövertäckningen, och flyghöjder påverkar kvaliteten på ortofoton och digitala ytmodeller. Samt undersöka hur objekthöjder påverkar bildövertäckningen. Kriteriet för studieområdet var att det skulle finnas ett högt objekt. Studien utfördes därför i Inre hamn i Karlstad som omfattar Löfbergsskrapan på ca 42 m. Studien avser UAVs som begränsas enligt Transportstyrelsens regler (TSFS 2017:110). Målet var att presentera referenstabeller till företag eller privatpersoner som samlar in mätdata med UAV. Data samlades in på flyghöjderna; 120 m och 90 m, med bildövertäckningarna; 60/60 %, 80/80 %, och 90/90 %. Höjddata för Löfbergsskrapan mättes in med Satlab GNSS. Resultatet visade att bildövertäckningen 60/60 % inte var användbart inom ett område med maximal objekthöjd 42 m. Det behövdes ≥80/80 % bildövertäckning för att få en bra markupplösning. I studien undersöktes även hur mycket bildövertäckningen kan förändras när objekt ligger under markytans plan. Resultatet visar att bildövertäckningen ökar när objektet eller ytan avviker tillräckligt mycket ifrån markytans plan och minskar om det går tillräckligt högt ovanför markytan. Slutsatsen föreslår att bildövertäckningen ska vara minst 80/80 % för flyghöjderna 120 m och 90 m. De inställningarna innebär att byggnader på ca 42 m höjd ska representeras med 2-3 cm markupplösning i ortofoton och digitala ytmodeller samt omfatta en resursvänlig metod. Slutsatsen menar att förändringen av bildövertäckningen varierar mellan 10-50 % när markytan ligger ca 42 m lägre än starthöjden för en UAV.
There are a few available studies purely focusing on the object heights significance on image overlap in UAV-photogrammetry. Therefore, it is interesting to examine how object heights, image overlaps, and altitudes affect each other and how they jointly affect data quality. The purpose is to examine how image overlap, and altitude affect the quality of orthophotos and digital elevation models. And also examine how object heights affect image overlap. The study area was selected with the criterion of including a high rise building. Therefore, the study area was Inre hamn in Karlstad City covering Löfbergsskrapan, a 42 m high coffee roasting house. The study refers to UAVs restricted according to rules set by Transportstyrelsen (TSFS 2017:110). The objective was to present useful reference tables for companies and individuals working with UAV-data. Data was collected on the altitudes; 120 m and 90 m with an image overlap of; 60/60 %, 80/80 %, and 90/90 %. Elevation values was collected with Satlab GNSS. Results showed that using an image overlap of 60/60 % for both altitudes was not viable in an area covering an object of 42 m high. The image overlap should be at least ≥80/80 % to cover objects of 42 m high. The objective was also to examine how image overlap differ when an object is below ground level. Results showed that image overlap increases when an object or surface differ 42 m from ground level and decreases if the object is above ground level. The conclusion suggests that in order to include objects of 42 m high in an area the image overlap should be at least 80/80 % for both altitudes (120 m and 90 m). With those settings the ground resolution in orthophotos and digital elevations models should be 2-3 cm. It was also estimated that the image overlap may alter from settings anywhere between 10-50 % when ground level is 42 m below the point of departure of the UAV.

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Martináková, Veronika. "Vyhodnocení snímků pořízených pomocí UAV." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-390231.

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The master´s thesis deals with the application of unmanned aerial vehicle (UAV) in photogrammetry and mapping. The first part describes the UAV that was used for imaging, legislative restrictions resulting from its operations, planning and realization of the flight. The second part of this thesis is focused on processing results, especially on evaluation the accuracy of the results gained by UAV with and without a GNSS module. The data are evaluated in the 3rd accuracy rating class (ČSN 01 3410). The theoretical principles are explained as well. The main aim of the thesis is to demonstrate the effective use of the GNSS module Emlid Reach and the unmanned aerial vehicle in geodesy.

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Barrett, Benjamin Joseph. "Field Validation of an Advanced Autonomous Method of Exterior Dam Inspection Using Unmanned Aerial Vehicles." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7463.

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The maintenance of infrastructure is critical to the well-being of society. This work focuses on a novel method for inspecting the exterior of dams using unmanned aerial vehicles (UAVs) in an automated fashion. The UAVs are equipped with optical sensors capturing still images. The resulting images are used to generate three-dimensional (3D) models using Structure from Motion (SfM) computer software. The SfM models are then used to inspect the exterior of the dam. As typical dam inspections entail completing a checklist of inspection items with varied degrees of precision (e.g. a concrete spillway may be finely inspected for cracking or joint deterioration while the general stability and water-tightness of a large embankment may be observed from a distance), a targeted inspection is also needed for the UAV method. In conjunction with the work presented in this thesis, a novel algorithm was developed which uses camera view planning across multiple proximity levels to generate a set of camera poses (positions and orientations) which can be collected in an autonomous UAV flight that facilitates generation of SfM models having tiered model quality for targeted inspection of infrastructure features. In this thesis, this novel algorithm and accompanying mobile application (referred to together as the novel advanced autonomous method) were field validated at Tibble Fork Dam, UT. The advanced autonomous method was compared to two other common image acquisition methods—basic autonomous and manual piloted—based on the SfM models produced from the collected image sets. The advanced autonomous method was found to produce models having tiered quality needed for efficient targeted inspection (25% and 50% higher resolution in medium and high priority target areas). The advanced autonomous method was found to produce models having on average 38% higher precise point accuracy (1.3cm) and 53% tighter surface reproducibility (for repeat inspections) (1.9cm) than basic autonomous and manual piloted image acquisition methods. The advanced autonomous method required on average 167% longer flight time and 38% fewer images than the other two methods, resulting in increased field time but decreased processing load. Additionally, viability of the advanced autonomous method for practical dam inspection was assessed through a case study inspection of Tibble Fork Dam using the collected SfM model and corresponding still images. The SfM model and corresponding images were found fully adequate for performing 94% of the inspection tasks and partially adequate for the remaining tasks. In consideration of this and other practical implementation factors such as time and safety, the method appears highly viable as an alternate to or supplement with traditional on-foot visual exterior inspection of dams such as Tibble Fork Dam. Suggestions for future work include adjustments to the optimization framework to improve field efficiency, development of a framework for cooperative inspection using UAV swarms, and development of a more automated workflow that would allow fully-remote dam inspections.

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Haslum, Patrik. "Prediction as a Knowledge Representation Problem : A Case Study in Model Design." Licentiate thesis, Linköping University, Linköping University, KPLAB - Knowledge Processing Lab, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5724.

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The WITAS project aims to develop technologies to enable an Unmanned Airial Vehicle (UAV) to operate autonomously and intelligently, in applications such as traffic surveillance and remote photogrammetry. Many of the necessary control and reasoning tasks, e.g. state estimation, reidentification, planning and diagnosis, involve prediction as an important component. Prediction relies on models, and such models can take a variety of forms. Model design involves many choices with many alternatives for each choice, and each alternative carries advantages and disadvantages that may be far from obvious. In spite of this, and of the important role of prediction in so many areas, the problem of predictive model design is rarely studied on its own.

In this thesis, we examine a range of applications involving prediction and try to extract a set of choices and alternatives for model design. As a case study, we then develop, evaluate and compare two different model designs for a specific prediction problem encountered in the WITAS UAV project. The problem is to predict the movements of a vehicle travelling in a traffic network. The main difficulty is that uncertainty in predictions is very high, du to two factors: predictions have to be made on a relatively large time scale, and we have very little information about the specific vehicle in question. To counter uncertainty, as much use as possible must be made of knowledge about traffic in general, which puts emphasis on the knowledge representation aspect of the predictive model design.

The two mode design we develop differ mainly in how they represent uncertainty: the first uses coarse, schema-based representation of likelihood, while the second, a Markov model, uses probability. Preliminary experiments indicate that the second design has better computational properties, but also some drawbacks: model construction is data intensive and the resulting models are somewhat opaque.

Report code: LiU-Tek-Lic-2002:15.

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Reali, Andrea. "Potentialities of Unmanned Aerial Vehicles in Hydraulic Modelling : Drone remote sensing through photogrammetry for 1D flow numerical modelling." Thesis, KTH, Byggvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234306.

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In civil and environmental engineering numerous are the applications that require prior collection of data on the ground. When it comes to hydraulic modelling, valuable topographic and morphology features of the region are one of the most useful of them, yet often unavailable, expensive or difficult to obtain. In the last few years UAVs entered the scene of remote sensing tools used to deliver such information and their applications connected to various photo-analysis techniques have been tested in specific engineering fields, with promising results. The content of this thesis aims contribute to the growing literature on the topic, assessing the potentialities of UAV and SfM photogrammetry analysis in developing terrain elevation models to be used as input data for numerical flood modelling. This thesis covered all phases of the engineering process, from the survey to the implementation of a 1D hydraulic model based on the photogrammetry derived topography The area chosen for the study was the Limpopo river. The challenging environment of the Mozambican inland showed the great advantages of this technology, which allowed a precise and fast survey easily overcoming risks and difficulties. The test on the field was also useful to expose the current limits of the drone tool in its high susceptibility to weather conditions, wind and temperatures and the restricted battery capacity which did not allow flight longer than 20 minutes. The subsequent photogrammetry analysis showed a high degree of dependency on a number of ground control points and the need of laborious post-processing manipulations in order to obtain a reliable DEM and avoid the insurgence of dooming effects. It revealed, this way, the importance of understanding the drone and the photogrammetry software as a single instrument to deliver a quality DEM and consequently the importance of planning a survey photogrammetry-oriented by the adoption of specific precautions. Nevertheless, the DEM we produced presented a degree of spatial resolution comparable to the one high precision topography sources. Finally, considering four different topography sources (SRTM DEM 30 m, lidar DEM 1 m, drone DEM 0.6 m, total station&RTK bathymetric cross sections o.5 m) the relationship between spatial accuracy and water depth estimation was tested through 1D, steady flow models on HECRAS. The performances of each model were expressed in terms of mean absolute error (MAE) in water depth estimations of the considered model compared to the one based on the bathymetric cross-sections. The result confirmed the potentialities of the drone for hydraulic engineering applications, with MAE differences between lidar, bathymetry and drone included within 1 m. The calibration of SRTM, Lidar and Drone based models to the bathymetry one demonstrated the relationship between geometry detail and roughness of the cross-sections, with a global improvement in the MAE, but more pronounced for the coarse geometry of SRTM.

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Martinez-Espejo, Zaragoza Isabel Verfasser], and Wolfgang [Akademischer Betreuer] [Niemeier. "Accuracy assessment of low-cost Terrestrial and UAV-based photogrammetry for Geomatics applications in architectural and cultural heritage contexts / Isabel Martinez-Espejo Zaragoza ; Betreuer: Wolfgang Niemeier." Braunschweig : Technische Universität Braunschweig, 2018. http://d-nb.info/1175816019/34.

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Güleç, Korumaz Saadet Armağan Verfasser], Wolfgang [Akademischer Betreuer] [Niemeier, and Grazia [Akademischer Betreuer] Tucci. "Improved Documentation of Cultural Heritage using Digital Photogrammetry with Visible and Thermal Images from Unmanned Aerial Vehicles (UAV) / Saadet Armağan Güleç Korumaz ; Wolfgang Niemeier, Grazia Tucci." Braunschweig : Technische Universität Braunschweig, 2019. http://d-nb.info/1191365360/34.

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INAMA, RICCARDO. "Fracture analysis and depositional geometries of a high relief carbonate platform from UAV photogrammetry and Digital Outcrop Modeling. The case of the Lastoni di Formin (Italian dolomites)." Doctoral thesis, Università degli studi di Pavia, 2021. http://hdl.handle.net/11571/1431676.

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Le piattaforme carbonatiche rappresentano un importante oggetto di studio in diversi campi applicativi delle geoscienze (ad esempio, per l'esplorazione di idrocarburi, l' approvvigionamento di risorse idriche e lo stoccaggio di CO2). Molto spesso, questo tipo di affioramenti sono altamente eterogenei in termini di architettura e distribuzione delle facies e sono spesso soggetti a intensa fratturazione. A loro volta, fratture e faglie rappresentano dei percorsi preferenziali per il flusso dei fluidi all'interno del corpo carbonatico, esercitando un forte impatto sulla qualità del giacimento. Tuttavia, molte delle caratteristiche salienti di un reservoir sono difficilmente rilevabili tramite tecniche di indagine geofisica, e le stratigrafie dei pozzi esplorativi rappresentano solo volumi limitati di roccia. In questo contesto, lo studio di piattaforme carbonatiche affioranti rappresenta una delle metodologie più efficaci per integrare i dati di pozzo nella valutazione delle caratteristiche di un giacimento. L'applicazione di modelli digitali dell'affioramento (Digital Outcrop Modeling o DOM) a questo tipo di studi fornisce un'importante fonte di dati per l'analisi e l'interpretazione dei sistemi carbonatici. Questo tipo di approccio multidisciplinare combina diverse aree di competenza, (geologia strutturale, sedimentologia, stratigrafia, informatica), che contribuiscono in diversa misura allo studio e all'interpretazione delle caratteristiche geologiche dell' affioramento in esame. In questo lavoro, sono state applicate avanzate tecniche di fotogrammetria digitale e Digital Outcrop Modeling allo studio di una piattaforma carbonatica di età triassica e più precisamente del Carnico (Lastoni di Formin, Dolomiti, Italia). L'acquisizione fotogrammetrica è stata eseguita sia da terra che tramite l' utilizzo di un veicolo a pilotaggio remoto (drone), che ha consentito di raggiungere porzioni inaccessibili e remote dell'affioramento e di acquisire grandi quantità di dati digitali in modo rapido ed efficace. Le immagini ottenute sono state elaborate utilizzando tecniche di Structure from Motion (SfM), che hanno reso possibile la ricostruzione 3D dell'affioramento che è stato successivamente visualizzato, analizzato e misurato in stereoscopia 3D. Inoltre, lo studio del DOM è stato affiancato a un'intensa campagna di rilevamento sul terreno, con l'obiettivo sia di validare i dati acquisiti in digitale che di integrare il set di misure. La combinazione di telerilevamento e rilevamento geologico tradizionale si è rivelata efficace per il raggiungimento degli obiettivi prefissati. La prima parte del progetto è stata dedicata alla ricostruzione dell'architettura e delle geometrie deposizionali della piattaforma dei Lastoni; nella seconda parte dello studio sono state eseguite l'analisi strutturale e la caratterizzazione del network di fratture della piattaforma stessa.
Carbonate platforms represent an important target of hydrocarbon exploration, water resources and CO2 sequestration and storage. In many cases, these types of sedimentary bodies are highly heterogeneous in terms of facies architecture and distribution, and are often characterized by intensive fracturing. Fractures and faults, in turn, represents preferential conducts for the fluids flow within the carbonate body and therefore their features (e.g. size, connection and distribution), strongly impact the quality of a carbonate body as a reservoir. Since most of these features are below seismic resolution, and wells, although providing key information, represent only small volumes of the rock, the study of outcrop analogues have become a powerful methodology in for the assessment of reservoirs. In particular, the analysis of outcrop analogues by the use of Digital Outcrop Modeling can provide relevant informations for the analysis and interpretation of carbonate systems, as it make it possible to collect large volumes of data from objects that for size and exposition would be otherwise inaccessibile. In the present study we applied Digital Outcrop Modeling and digital photogrammetry to the study of a Triassic isolated platform (Lastoni di Formin, Dolomites, Italy), to reconstruct the platform architecture and the distribution and genesis of the fracture pattern that affect it. The photogrammetric acquisition was performed both from the ground and by the use of an Unmanned Aerial Vehicles (drone), that allowed to reach inaccessible and remote portions of the outcrop and to acquire large amounts of digital data in a quick and effective way. The obtained images were processed using Structure from Motion (SfM) techniques, producing the 3D Digital Outcrop Model (DOM). The DOM was subsequently visualized, analyzed and sampled in 3D stereoscopic environment. Furthermore, the study was supported by an intense field survey campaign, with the aim of both validating the digitally acquired data and integrating the set of measurements. The combination of remote sensing and traditional field studies has proven to be effective in achieving the objectives of the project. A first part of the study was dedicated to the reconstruction of the architecture and depositional geometries of the platform. Secondly, the structural analysis of the Lastoni platform and the characterization of the fracture network were undertaken.

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Thornton, Victor. "DETERMINING TIDAL CHARACTERISTICS IN A RESTORED TIDAL WETLAND USING UNMANNED AERIAL VEHICLES AND DERIVED DATA." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5369.

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Unmanned aerial vehicle (UAV) technology was used to determine tidal extent in Kimages Creek, a restored tidal wetland located in Charles City County, Virginia. A Sensefly eBee Real-Time Kinematic UAV equipped with the Sensor Optimized for Drone Applications (SODA) camera (20-megapixel RGB sensor) was flown during a single high and low tide event in Summer 2017. Collectively, over 1,300 images were captured and processed using Pix4D. Horizontal and vertical accuracy of models created using ground control points (GCP) ranged from 0.176 m to 0.363 m. The high tide elevation model was subtracted from the low tide using the ArcMap 10.5.1 raster calculator. The positive difference was displayed to show the portion of high tide that was above the low tide. These results show that UAVs offer numerous spatial and temporal advantages, but further research is needed to determine the best method of GCP placement in areas of similar forest structure.

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d'ALTILIA, LUCA. "Analisi spaziali in ambiente gis open source per lo studio di contesti archeologici della Daunia medievale." Doctoral thesis, Università di Foggia, 2016. http://hdl.handle.net/11369/363017.

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Le ricerche condotte da chi scrive nell'ambito del progetto, hanno visto in questi anni l'utilizzo di molteplici approcci tecnici e metodologici alla materia. Il progetto trae origine ed ispirazione da una sperimentazione applicativa di GIS intra-site già condotta in precedenza sul sito medievale abbandonato di Montecorvino (Volturino, FG). Pur nella ricerca di una continuità metodologica, questo lavoro intende estendere le potenzialità di ricerca in senso geografico e tipologico, mirando a coniugare tipologie di analisi Intra-site ed Inter-site e di conseguenza l’attività di scavo stratigrafico e lo studio del paesaggio archeologico. L’obiettivo preposto è utilizzare i risultati delle analisi spaziali, in particolare delle Viewshed, Site Catchment e Cost Surface Analyses, per formulare nuove ipotesi di lettura riguardanti le dinamiche endogene di occupazione e di popolamento delle regioni in esame. L'analisi Intra-site ha previsto lo studio in ambiente GIS Open Source del microrilievo, al fine di esaminare, da una nuova prospettiva di indagine, forme di fortificazione in contesti insediativi di altura e di pianura del medioevo di Capitanata. Fondamentale è risultato l'apporto di nuove tecnologie per il rilievo, la documentazione e la comunicazione in archeologia, come l'aerofotogrammetria da APR, la Structure From Motion e la stampa 3D.

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Freeman, Michael James. "The Integration of Iterative Convergent Photogrammetric Models and UAV View and Path Planning Algorithms into the Aerial Inspection Practices in Areas with Aerial Hazards." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8738.

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Small unmanned aerial vehicles (sUAV) can produce valuable data for inspections, topography, mapping, and 3D modeling of structures. Used by multiple industries, sUAV can help inspect and study geographic and structural sites. Typically, the sUAV and camera specifications require optimal conditions with known geography and fly pre-determined flight paths. However, if the environment changes, new undetectable aerial hazards may intersect new flight paths. This makes it difficult to construct autonomous flight path missions that are safe in post-hazard areas where the flight paths are based on previously built models or previously known terrain details. The goal of this research is to make it possible for an unskilled pilot to obtain high quality images at key angles which will facilitate the inspections of dangerous environments affected by natural disasters through the construction of accurate 3D models. An iterative process with converging variables can circumvent the current deficit in flying UAVs autonomously and make it possible for an unskilled pilot to gather high quality data for the construction of photogrammetric models. This can be achieved by gaining preliminary photogrammetric data, then creating new flight paths which consider new developments contained in the generated dense clouds. Initial flight paths are used to develop a coarse representation of the target area by aligning key tie points of the initial set of images. With each iteration, a 3D mesh is used to compute a new optimized view and flight path used for the data collection of a better-known location. These data are collected, the model updated, and a new flight path is computed until the model resolution meets the required heights or ground sample distances (GSD). This research uses basic UAVs and camera sensors to lower costs and reduce the need for specialized sensors or data analysis. The four basic stages followed in the study include: determination of required height reductions for comparison and convergent limitation, construction of real-time reconnaissance models, optimized view and flight paths with vertical and horizontal buffers constructed from previous models, and develop an autonomous process that combines the previous stages iteratively. This study advances the use of autonomous sUAV inspections by developing an iterative process of flying a sUAV to potentially detect and avoid buildings, trees, wires, and other hazards in an iterative manner with minimal pilot experience or human intervention; while optimally collecting the required images to generate geometric models of predetermined quality.

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Camargo, Marcel Pinton de. "Aerial machine vision, geographical information system and hue for pattern classification in agriculture." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-17012019-180101/.

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In this research we aim to achieve cybernetic cohesion information flow in precision agriculture, integrating machine learning methods, computer vision, geographical information system and UAV-photogrammetry in an irrigated area with slaughterhouse wastewater, under five treatments (W100 - irrigation with superficial water and 100% of nitrogen mineral fertilization, E0, E33, E66 and E100 - irrigation with treated effluent from slaughterhouse and addition of 0, 33, 66 and 100% of nitrogen mineral fertilization, respectively) and four replications on grassland (Cynodon dactylon (L.) Pers.). Several images (between one hundred and two hundred) with red, green, blue (RGB) color model were captured using a quadcopter flying at 20 meter altitude and obtaining spatial resolution of 1 centimeter on a surface of approximately 0.5 ha. The images were orthorectified together with nine ground control points done by differential global positioning system (GPS), both processed in the Agisoft PhotoScan software. Thirteen photogrammetric projects were done over time with 30-day revisit, the root mean squared error (RMSE) was used as accuracy measurement, and reached values lower than 5 centimeters for x, y and z axis. The orthoimage obtained with unmanned aerial vehicle (UAV) photogrammetry was changed from RGB to hue, saturation, value (HSV) color model, and the hue color space was chosen due to independence of illumination, beyond it has a good description of exposure of soil and vegetation, but it is dependent of light source temperature, so difficult to estabilish a static threshold, so we selected an unsupervised classification method, K-Means, to classify the unknown patterns along the area. Polygons were drawn delimiting the area represented by each portion and a supervised classification method based on entropy was used, the decision tree, to explore and find patterns that recognize each treatment. These steps are also displayed in forms of georeferenced thematic maps and were executed in the open source softwares Python, QGIS and Weka. The rules defined on the hue color space reached an accuracy of 100% on the training set, and provided a better understanding about the distribution of soil and vegetation on the parcels. This methodology shows a great potential for analysis of spectral data in precision agriculture.
Nesta pesquisa pretendemos alcançar a coesão cibernética no fluxo de informações dentro da agricultura de precisão, integrando métodos de aprendizagem de máquinas, visão computacional, sistema de informação geográfica e aerofotogrametria em uma área irrigada com efluente de matadouro, sob cinco tratamentos (W100 - irrigação com água superficial e 100 % de adubação mineral nitrogenada, E0, E33, E66 e E100 - irrigação com efluente tratado de abatedouro e adição de 0, 33, 66 e 100% de adubação mineral nitrogenada, respectivamente) e quatro repetições em pastagem (Cynodon dactylon (L.) Pers.) Várias imagens (entre cem e duzentas) com modelo de cor vermelho, verde e azul (RGB) foram capturadas por um quadricóptero voando a 20 metros de altitude, e obtendo resolução espacial de 1 centímetro em uma superfície de aproximadamente 0.5 ha. As imagens foram ortorretificadas juntamente com nove pontos de controle, realizados pelo sistema de posicionamento global diferencial (GPS), ambos processados no software Agisoft PhotoScan. Treze projetos fotogramétricos foram realizados ao longo do tempo com revisita de 30 dias, a raiz do erro quadrático médio (RMSE) foi usada como medida de acurácia e atingiu valores menores que 5 centímetros para os eixos x, y e z. A ortoimagem obtida com a fotogrametria do veículo aéreo não tripulado (UAV) foi alterada de RGB para matiz, saturação, valor (HSV) e o espaço de cor matiz foi escolhido devido a independência da iluminação, além de ter boa descrição da exposição do solo e vegetação. Entretanto este é dependente da temperatura da fonte de luz, portanto difícil de se estabelecer um limiar estático, logo selecionamos um método de classificação não supervisionado, o K-Means, para classificar os padrões desconhecidos ao longo da área. Polígonos foram traçados delimitando a área representada por cada parcela e um método supervisionado de classificação baseado na entropia foi utilizado, a árvore de decisão, para explorar e encontrar padrões que reconheçam cada tratamento. Essas etapas também são exibidas em formas de mapas temáticos georeferenciados e foram executadas nos softwares de código aberto Python, QGIS e Weka. As regras definidas no espaço de cor matiz atingiram uma acurácia de 100% no conjunto de treinamento e proporcionaram um melhor entendimento sobre a distribuição do solo e da vegetação nas parcelas. Esta metodologia mostra um grande potencial para análise de dados na agricultura de precisão.

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Andersson, Elias. "Dokumentation av en trafikolycka med handhållen laserskanning och UAS-fotogrammetri : En utvärdering av punktmolnens lägesosäkerhet och visuella kvalitet." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-36472.

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I samband med en trafikolycka är det ofta viktigt att återställa platsen till det normala så snabbt som möjligt. Emellanåt måste olycksplatsen dokumenteras för att orsaken till olyckan ska kunna utredas i ett senare skede. Traditionellt har detta arbete utförts genom att fotografera platsen och mäta olika avstånd. På senare tid har även terrester laserskanning kommit att bli ett tillförlitligt alternativ. Med det sagt är det tänkbart att även fotogrammetri och andra typer av laserskanning skulle kunna användas för att uppnå liknande resultat. Syftet med denna studie är att utforska hur handhållen laserskanning och UAS-fotogrammetri kan användas för att dokumentera en trafikolycka. Detta uppnås genom att utvärdera punktmolnens lägesosäkerhet och visuella kvalitet. Vidare utforskas fördelar och nackdelar med respektive metod, bland annat sett till tidsåtgång och kostnader, för att slutligen komma fram till vilken metod som lämpar sig bäst för att dokumentera en trafikolycka. En trafikolycka med två inblandade bilar iscensattes och laserskannades till en början med den handhållna laserskannern Leica BLK2GO. Därefter samlades bilder in med den obemannade flygfarkosten Leica Aibot följt av att ett referenspunktmoln skapades med den terrestra laserskannern Leica C10. Genom att jämföra koordinater för kontrollpunkter i referenspunktmolnet med koordinaterna för motsvarande kontrollpunkter i de två andra punktmolnen kunde deras lägesosäkerheter bestämmas. Studiens resultat visar att både punktmolnet som framställdes med handhållen laserskanning och UAS-fotogrammetri har en lägesosäkerhet (standardosäkerhet) i 3D på 0,019 m. Båda metoderna är tillämpliga för att dokumentera en trafikolycka, men jämfört med terrester laserskanning är punktmolnen dock bristfälliga på olika sätt. BLK2GO producerar ett förhållandevis mörkt punktmoln och mörka objekt avbildas sämre än ljusare föremål. I punktmolnet som framställdes med Leica Aibot förekom påtagliga håligheter i bilarnas karosser. Handhållen laserskanning är en tidseffektiv metod medan UAS-fotogrammetri kan utföras till en lägre kostnad. Sammanfattningsvis går det inte att dra någon entydig slutsats om vilken metod som lämpar sig bäst för att dokumentera en trafikolycka. Valet beror på vilka omständigheter som råder på olycksplatsen.
In the event of a traffic accident, it is often important to restore the site to its normal condition as fast as possible. Occasionally, the accident scene must be documented so that the cause of the accident can be investigated at a later stage. Traditionally, this work has been performed by taking pictures of the site and measuring different distances. Lately, terrestrial laser scanning has also become a reliable alternative. With that said, it is possible that photogrammetry and other types of laser scanning also could be utilized to achieve similar results. The aim of this study is to investigate how handheld laser scanning and UAS photogrammetry can be used to document a traffic accident. This is achieved by examining the positional uncertainty and visual quality of the point clouds. Moreover, the advantages and disadvantages of each method are explored, for instance in terms of time consumption and costs, in order to finally come to a conclusion of which method is best suited for documenting a traffic accident. A traffic accident with two involved cars was staged and initially laser scanned with the handheld laser scanner Leica BLK2GO. Thereafter, pictures were collected with the unmanned aerial vehicle Leica Aibot followed by the creation of a reference point cloud with the terrestrial laser scanner Leica C10. By comparing the coordinates of control points in the reference point cloud with the coordinates of the corresponding control points in the two other point clouds, their positional uncertainty could be determined. The results of the study show that both the point cloud produced by the handheld laser scanner and UAS photogrammetry have a positional uncertainty (standard uncertainty) of 0.019 m. Both methods are applicable for documenting a traffic accident but compared to terrestrial laser scanning, the point clouds are deficient in different ways. BLK2GO produces a relatively dark point cloud and dark objects are reproduced worse than lighter objects. In the point cloud produced by Leica Aibot, there were noticeable cavities in the bodies of the cars. Handheld laser scanning is a time-efficient method while UAS photogrammetry can be performed at a lower cost. In conclusion, it is not possible to arrive at an unambiguous conclusion with regards to which method that is best suited for documenting a traffic accident. The choice depends on the prevailing circumstances at the accident scene.

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Ekberg, Bergman Emelie. "Jämförelse av metod vid stabilitetsanalys i bergslänter." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-352090.

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En bergslänts stabilitet styrs av berggrundens egenskaper, så som sprickegenskaper och bergkvalité. För att uppnå önskad stabilitet i en bergslänt behöver de bergmekaniska parametrarna kartläggas och analyseras för att fastställa risker och stabilitetsåtgärder. Syftet med studien är att utvärdera kvalitén på bergteknisk data från digitalfotogrammetriska 3D-modeller genom att jämföra resultatet med manuella mätningar från konventionell kartläggning. Målet är även att utforska potentialen för användning av fotogrammetrisk 3D-modellering vid stabilitetsanalyser i bergslänter genom att utvärdera den bergtekniska analys som kan göras utifrån fotogrammetrisk data. Sprickmätningar framtagna från 3D-modellen visade sig ha samma kvalité som manuella mätningar tagna enligt konventionell metod. Den UAS-baserade fotogrammetrin kan dock inte ersätta den konventionella analysen helt vid stabilitetsanalyser men kan användas som ett kompletterande verktyg i bergtekniska undersökningar. Fotogrammetrin möjliggör datainsamling från ett säkrare avstånd vilket minskar riskmomenten som den konventionella metoden medför vid arbete i fält. Den digitala metoden visade sig även ha fler fördelar såsom möjligheten av kartläggning och analysering framför datorn för mindre tids- och kostnadskrävande moment, digital datalagring samt att slänter med begränsad åtkomst kan karteras.
The stability of a rock slope is controlled by the rock’s mechanical properties, such as rock quality and facets. To achieve the desired stability in a rock slope, the mechanical parameters need to be mapped and analysed to determine possible failures and decide necessary stability measures. The purpose of this study is to evaluate the quality of rock technical data from digital photogrammetry 3D models by comparing the result with manual measurements from conventional mapping. The goal is also to explore the potential uses of photogrammetric 3D models for rock slope stability analyses by evaluate the photogrammetric data. Facets extracted from 3D models were found to have the same quality as manual measurements. However, the UAS-based method cannot completely replace the conventional method but can be useful as a complementary tool. Photogrammetry enables the collection of data from a safer distance, which reduces workplace hazards that the conventional method entails. The digital method also proved to have more advantages, such as the possibility of digital mapping and analysing which is less costly and time-consuming, digital data storage and the possibility to access outcrops that can’t be mapped with manually measurements due to inaccessibility.

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Gibaja, Bautista Roberto Sebastian, and Ruiz Rodrigo David Rojas. "Controles topográficos en pendientes pronunciadas para evitar deslizamientos utilizando vehículos aéreos no tripulados (UAV)." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/657242.

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El siguiente trabajo de investigación se realizó en la bajada de Armendáriz, acantilado de la Costa Verde, distrito de Miraflores, provincia de Lima, Perú. En este se propone la creación de una metodología de control topográfico en la zona anteriormente mencionada, esto debido a que se presentan constantes deslizamientos de rocas por diversos factores como la erosión marina y el tránsito vehicular cercano. Usando información del Instituto Geográfico Nacional (IGN), información brindada por profesionales en el área e información obtenida del vuelo fotogramétrico con dron Mavic 2 Pro realizado, se elaboró la comparación de perfiles longitudinales de los años 2019, 2020 y 2021 en una zona del talud que sufre deslizamientos de manera constante. Con el fin de mantener la precisión y coherencia de los resultados, se procesó la información obtenida para lograr las mismas características entre los planos de curvas de nivel que sirvieron para la realización de los cálculos y el posterior análisis. Entre los principales resultados obtenidos se determinó que la parte superior del talud se redujo 1.30 m durante los años evaluados, la parte media una reducción de 0.50 m y la parte inferior un incremento de 1.20 m. Con los resultados mencionados anteriormente se determinó la tendencia a sufrir derrumbes que posee la zona del talud evaluada y se propuso la realización de vuelos fotogramétricos anuales para el seguimiento del comportamiento del talud con el fin de implementar obras de ingeniería de contención en las zonas vulnerables.
The following research work was carried out in the Bajada de Armendariz, cliff of the Costa Verde, district of Miraflores, province of Lima, Peru. In this, the creation of a topographic control methodology in the aforementioned area is proposed, due to the fact that there are constant rock slides due to various factors such as marine erosion and nearby vehicular traffic. Using information from the National Geographic Institute (IGN), information provided by professionals in the area and information obtained from the photogrammetric flight with a Mavic 2 Pro drone carried out. the comparison of longitudinal profiles of the years 2019, 2020 and 2021 in an area of the slope was elaborated that suffers landslides constantly. In order to maintain the precision and coherence of the results, the information obtained was processed to achieve the same characteristics between the contour planes that were used to carry out the calculations and the subsequent analysis. Among the main results obtained, it was determined that the upper part of the slope decreased 1.30 m during the evaluated years, the middle part a reduction of 0.50 m and the lower part an increase of 1.20 m. With the aforementioned results, the tendency to collapse in the area of the evaluated slope was determined and it was proposed to carry out annual photogrammetric flights to monitor the behavior of the slope in order to implement containment engineering works in vulnerable areas.
Trabajo de investigación

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SAMMARTANO, GIULIA. "Suitability Of 3D Dense Models For Rapid Mapping Strategies On Cultural Heritage Documentation And Conservation. Validation of metric and non-metric information extraction from integrated solutions." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2703098.

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This dissertation deals with the suitability of digital models for the 3D documentation of built heritage (BH), in terms of its resolution, measure and representation regarding the building’s morphology and state of conservation. Specifically, the research enquires into the 3D models’ consistency and validation, generated by new methodological developments of geomatics-integrated techniques for obtaining geospatial data, by means of rapid mapping solutions in 3D survey, generally with low-cost approaches, to obtain metric and non-metric definition of the historical structures. Starting from the bounding of the concept of user-oriented models in the reality-based modelling issues at the first part of the dissertation, the documentation of cultural heritage (CH) in critical contexts is defined as investigation workspace. The established workflows of the digital metric survey based on range-based and image-based sensors are analyzed in the second part, and the possible integrated acquisition and processing phases on the point clouds data treatment for the surface model definition are proposed and validated. The assessment issues are weighted on employed techniques, well-established and more innovative, and on the initially introduced requirements about scale accuracy and achievable details. The aim of this research is thus to focus on the 3D model features and their confidence levels to define and classify the extracted multi-scale geometric and radiometric information that can be useful to be addressed toward interdisciplinary interventions on the state of conservation, on the damage mapping and assessment around cultural heritage assets. This content is bound around the 3D model, according to a multi-parameter framework that wants to cover the overall validation attributes, such as: operational efficiency or the practicality and sustainability of data achievement; reliability or the confidence level of the metric contents on the model; contents or the richness of the embedded data; completeness or the comprehensiveness of gatherable information. The extensive testing, addressed in the fourth part of the discussion, is based on a set of examples regarding the analyzed BH typologies located in the different urban and landscape contexts, featured by increasing levels of critical issues. It aims is the supporting the comparative multi-parameter evaluation and validation in the central part of the dissertation. Herein, the validation of 3D models is proposed from integrated workflows which take into account consolidated approaches (like terrestrial laser scanning or close-range photogrammetry) flanked by rapid mapping strategies with the employment of alternative techniques (such as the UAV photogrammetry, in the nadir and oblique configurations, and the portable Mobile Mapping Systems). The information richness, according to a 3D integration perspective, demonstrates across the dataset presentation and the final discussion, the promising and flexible ability of documenting the morphology and material characterization of complex historical structures, even proving their aptitude to support the mapping of structures consistence and conservation in case of emergency and damage assessment.

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Abranches, Gonçalo Botelho de Sousa. "Determinação da qualidade geométrica de superfície refletoras com recurso à fotogrametria." Master's thesis, Universidade de Évora, 2018. http://hdl.handle.net/10174/23893.

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Neste trabalho é utilizada a Fotogrametria como ferramenta para avaliação geométrica de concentradores solares térmicos. Coletores do tipo cpc – coletores parabólicos compostos são submetidos a diversas experiências fotogramétricas e avaliados quanto à sua forma. Outros objetos com superfícies refletoras e não refletoras como concentradores solares ptc – parabolic through concentrator e fornos solares também são alvo de experiências fotogramétricas com o objetivo de estudar os efeitos de diferentes tipos de superfícies na fotogrametria. É também comparado o modelo 3D do concentrador ideal com aquele que foi obtido através da fotogrametria, para o que foi feito um estudo exaustivo, verificando as diferenças geométricas entre os dois modelos, bem como os efeitos dessas diferenças físicas na reflexão dos raios solares, ou seja, na energia captada pelo concentrador; Abstract: Geometrical assessment of reflective surfaces using photogrammetry This paper uses Photogrammetry as a tool for the geometric evaluation of solar concentrators. Collectors of the cpc type - compound parabolic collectors are submitted to several photogrammetric experiments and evaluated for their shape. Other objects with reflecting and non-reflecting surfaces such as ptc - parabolic through concentrators and solar ovens are also the subject of photogrammetric experiments to study the effects of different types of surfaces in photogrammetry. There is also a comparison between the 3D model of the ideal concentrator and that obtained by photogrammetry. An exhaustive study was done verifying the geometric differences between the two models as well as the effects of these physical differences in the reflection of the solar rays that represent the energy captured by the concentrator.

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Furlan, Lucas Moreira. "Hidrodinâmica em área úmida de cerrado na chapada sedimentar do oeste mineiro /." Rio Claro, 2019. http://hdl.handle.net/11449/182498.

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Orientador: Vania Silvia Rosolen
Resumo: No Brasil, a captação de água para irrigação é de aproximadamente 1000 m³/s, caracterizando o maior consumo de água do território nacional. Como possível ambiente de estoque natural de água que cobre quase 20% do território, as áreas úmidas vem sendo drasticamente reduzidas pela conversão do uso da terra. As áreas úmidas promovem a infiltração das águas superficiais e caracterizam áreas de recarga de aquíferos. Nesse sentido, medidas e modelos relacionados aos solos com propriedades hidromórficas e seu papel na recarga de aquíferos constituem um desafio para compreender a dinâmica entre solo e água, a fim de atender o desenvolvimento sustentável. Neste estudo, análises baseadas em sensoriamento remoto, com o uso de sensores ópticos de alta resolução espaço-temporal a bordo de Veículos Aéreos Não Tripulados (VANT), associadas ao uso de técnicas não invasivas que permitem o mapeamento da arquitetura subsuperficial dos sistemas pedológicos (ensaios geofísicos de Eletrorresistividade, por Tomografia Elétrica), foram aplicadas para compreender a relação água-solo superficial e subsuperficial em uma área úmida da chapada sedimentar do oeste mineiro. A integração destes dados com ensaios in situ de permeabilidade e de densidade e granulometria dos solos, permitiu uma abordagem ampla e tridimensional do comportamento dos parâmetros hidrogeológicos na área úmida. Os resultados permitiram determinar que a área úmida estudada é uma depressão que possui três compartimentos com distinções... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre

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Edlund, Fredrik. "GIS-baserad analys och validering av habitattyper efter dammutrivning." Thesis, Karlstads universitet, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-84563.

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Efter att EU införde ett ramverk år 2000 rörande regionens vattenanvändning, vattendirektivet, beslöt Sveriges regering att från och med sommaren 2020 ompröva rikets vattendammar. I de fall rådande vattenanvändning inte uppfyller de krav som anges i ramverket kan dammutrivning bli aktuellt. Syftet med studien är undersöka och utveckla en metod att utvärdera förändringar av strömhabitat uppströms ett vattendrag efter en dammutrivning. Studieområdet utgörs och begränsas av datamängden i form av flygfoton insamlade med UAV vid två tillfällen över samma område. Även batymetriska data över vattendragets botten från en bottenskanning har använts således även Lantmäteriets nationella höjdmodell. Två fotogrammetriprogram användes i arbetet, dels för att skapa en ortomosaik från flygfoton men även för att utföra en bildnormalisering. GIS programvaran ArcGIS Pro tillhandahåller flera algoritmer för klassificering av raster. Algoritmerna SVM och RT, viktades mot varandra och SVM användes vidare i metoden. Med olika generaliserings-verktyg kunde strömhabitat identifieras och förstärkas. Även olika terrängmodeller skapades från flygfoton och Lantmäteriets nationella höjdmodell. Dessa granskades mot varandra utifrån olika aspekter som variationer i bland annat detaljrikedom, generaliseringsgrad och återspeglandet av vattenytan. Slutsatsen av studien är att klassificering av strömhabitat kan göras i ett GIS-program med en lägesosäkerhet på mellan 25 och 40 %, beroende på vilka strömhabitat som ska klassificeras. Efter utrivningen uppstod 17 zoner med förändrade strömhabitat vilket var två mer än vad prognoser förutsatt. Vidare påverkades vattenvolymen markant då en minskning på ca 40 % skedde från 2018 till 2020. En areal av ca 1,5 hektar berördes då gammal älvbotten blev torrlagd i samband med dammutrivningen. Ett samband syntes mellan avståndet från kraftverket och torrlagd botten då dessa ytor sågs minska i storlek i takt med att avståndet ökade. Att undersöka vart vattennivån påverkats som mest var inte möjligt i brist på data. Studien har utvecklat en metod att analysera en dammutrivnings påverkan på ett vattendrag med data från UAV och bottenskanning.

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Carretta, Nicola. "Confronto tra tecniche di remote sensing per la caratterizzazione di un ammasso roccioso presso le Gole di Scascoli, Loiano (BO)." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11882/.

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Il versante sinistro delle Gole di Scascoli (BO) è caratterizzato da una marcata tendenza evolutiva per crollo e ribaltamento. Negli ultimi 25 anni si sono verificati eventi parossistici con volumi di roccia coinvolti rispettivamente di 7000 m3, 20000 m3 e 35000 m3. Il sito è di grande rilevanza a causa del forte fattore di rischio rappresentato per la strada di fondovalle ad esso adiacente. Il lavoro di tesi è stato finalizzato allo studio dei fenomeni di versante di una parete rocciosa inaccessibile nota in letteratura come “ex-Mammellone 1” mediante tecniche di telerilevamento quali TLS (Terrestrial Laser Scanning) e CRP (Close Range Photogrammetry) al fine affiancare il rilievo geomeccanico soggettivo dell’area svolto nel 2003 da ENSER Srl in seguito ai fenomeni di crollo del 2002. Lo sviluppo di tecnologie e metodi innovativi per l’analisi territoriale basata sull’impiego di UAV (Unmanned Aerial Vehicle, meglio noti come Droni), associata alle tecniche di fotogrammetria digitale costituisce un elemento di notevole ausilio nelle pratiche di rilevamento in campo di sicurezza e tempi di esecuzione. Il lavoro ha previsto una prima fase di rilevamento areo-fotogrammetrico mediante strumentazione professionale e amatoriale, a cui è seguita l’elaborazione dei rispettivi modelli. I diversi output sono stati confrontati dal punto di vista geomorfologico, geometrico, geomeccanico e di modellazione numerica di caduta massi. Dal lavoro è stato possibile indagare l’evoluzione morfologica del sito in esame negli ultimi 10 anni, confrontare diversi metodi di rilevamento e analisi dati, sperimentare la robustezza e ripetibilità geometrica del metodo fotogrammetrico per il rilievo di fronti rocciosi e mettere a punto un metodo semiautomatico di individuazione e analisi delle giaciture delle discontinuità.

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Gademer, Antoine. "Réalité terrain étendue : une nouvelle approche pour l'extraction de paramètres de surface biophysiques et géophysiques à l'échelle des individus." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00583243.

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L'extraction des paramètres de surface est une activité essentielle des Sciences de la vie et de la Terre. Ce mémoire propose une nouvelle méthodologie pour l'analyse des paramètres biophysiques et géophysiques, appelée Réalité Terrain Étendue, et qui mêle les avantages des relevés terrain et de la télédétection. Nous nous sommes en particulier attachés aux avantages de la télédétection basse altitude et d'un système micro-drone multi-caméras pour la cartographie de la dynamique de la végétation à l'échelle des individus. Cette problématique pose de nombreuses contraintes sur notre système car l'identification des arbrisseaux nécessite des capteurs innovants et une adaptation aux cycles phénologiques pour améliorer leur capacité de discrimination. La télédétection basse altitude semble être une solution intéressante en terme de résolution spatiale et de souplesse opérationnelle, et le développement des micro-drones civils permet des outils d'autant plus performants et fiables pour les missions terrain. Nous avons donc mis en place un système complet de drone avec une charge utile spécifique emportant simultanément trois appareils photographiques pour l'acquisition à la demande d'images obliques, stéréoscopiques ou multispectrales et permettant le développement de nouvelles méthodes d'identification de la végétation. Enfin, en participant à un relevé terrain du Muséum national d'Histoire naturelle, nous avons validé l'intérêt de notre système pour la cartographie de la dynamique de la végétation. Ce travail s'ouvre sur de nombreuses applications et perspectives de recherche, comme l'extraction de paramètres biophysiques par stéréo-restitution et l'agriculture de précision

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Moore, Alahna. "Using Digital Mapping Techniques to Rapidly Document Vulnerable Historical Landscapes in Coastal Louisiana: Holt Cemetery Case Study." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2477.

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This thesis outlines a technique for rapid documentation of historic sites in volatile cultural landscapes. Using Holt Cemetery as an exemplary case study, a workflow was developed incorporating RTK terrain survey, UAS aerial imagery, photogrammetry, GIS, and smartphone data collection in order to create a multifaceted database of the material and spatial conditions, as well as the patterns of use, that exist at the cemetery. The purpose of this research is to create a framework for improving the speed of data creation and increasing the accessibility of information regarding threatened cultural resources. It is intended that these processes can be scaled and adapted for use at any site, and that the products generated can be utilized by researchers, resource management professionals, and preservationists. In utilizing expedited methods, this thesis specifically advocates for documentation of sites that exist in coastal environments and are facing imminent destruction due to environmental degradation.

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(9188615), Lisa Marie Laforest. "SPATIAL AND TEMPORAL SYSTEM CALIBRATION OF GNSS/INS-ASSISTED FRAME AND LINE CAMERAS ONBOARD UNMANNED AERIAL VEHICLES." Thesis, 2020.

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Unmanned aerial vehicles (UAVs) equipped with imaging systems and integrated global navigation satellite system/inertial navigation system (GNSS/INS) are used for a variety of applications. Disaster relief, infrastructure monitoring, precision agriculture, and ecological forestry growth monitoring are among some of the applications that utilize UAV imaging systems. For most applications, accurate 3D spatial information from the UAV imaging system is required. Deriving reliable 3D coordinates is conditioned on accurate geometric calibration. Geometric calibration entails both spatial and temporal calibration. Spatial calibration consists of obtaining accurate internal characteristics of the imaging sensor as well as estimating the mounting parameters between the imaging and the GNSS/INS units. Temporal calibration ensures that there is little to no time delay between the image timestamps and corresponding GNSS/INS position and orientation timestamps. Manual and automated spatial calibration have been successfully accomplished on a variety of platforms and sensors including UAVs equipped with frame and push-broom line cameras. However, manual and automated temporal calibration has not been demonstrated on both frame and line camera systems without the use of ground control points (GCPs). This research focuses on manual and automated spatial and temporal system calibration for UAVs equipped with GNSS/INS frame and line camera systems. For frame cameras, the research introduces two approaches (direct and indirect) to correct for time delay between GNSS/INS recorded event markers and actual time of image exposures. To ensure the best estimates of system parameters without the use of ground control points, an optimal flight configuration for system calibration while estimating time delay is rigorously derived. For line camera systems, this research presents the direct approach to estimate system calibration parameters including time delay during the bundle block adjustment. The optimal flight configuration is also rigorously derived for line camera systems and the bias impact analysis is concluded. This shows that the indirect approach is not a feasible solution for push-broom line cameras onboard UAVs due to the limited ability of line cameras to decouple system parameters and is confirmed with experimental results. Lastly, this research demonstrates that for frame and line camera systems, the direct approach can be fully-automated by incorporating structure from motion (SfM) based tie point features. Methods for feature detection and matching for frame and line camera systems are presented. This research also presents the necessary changes in the bundle adjustment with self-calibration to successfully incorporate a large amount of automatically-derived tie points. For frame cameras, the results show that the direct and indirect approach is capable of estimating and correcting this time delay. When a time delay exists and the direct or indirect approach is applied, horizontal accuracy of 1–3 times the ground sampling distance (GSD) can be achieved without the use of any ground control points (GCPs). For line camera systems, the direct results show that when a time delay exists and spatial and temporal calibration is performed, vertical and horizontal accuracy are approximately that of the ground sample distance (GSD) of the sensor. Furthermore, when a large artificial time delay is introduced for line camera systems, the direct approach still achieves accuracy less than the GSD of the system and performs 2.5-8 times better in the horizontal components and up to 18 times better in the vertical component than when temporal calibration is not performed. Lastly, the results show that automated tie points can be successfully extracted for frame and line camera systems and that those tie point features can be incorporated into a fully-automated bundle adjustment with self-calibration including time delay estimation. The results show that this fully-automated calibration accurately estimates system parameters and demonstrates absolute accuracy similar to that of manually-measured tie/checkpoints without the use of GCPs.

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Chiang, Shih-Peng, and 蔣士朋. "UAV Photogrammetry for Beach Topography Surveying." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/j3e763.

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碩士
國立臺灣海洋大學
河海工程學系
105
The rationality of the special planning in coastal areas requires to grasp primarily the change mechanism of site topography. Therefore, this research takes the advantages of direct field measurements and indirect remote sensing, and Unmanned Aerial Vehicle(UAV) which is convenient to carry, flying at low altitude and moving quickly, Global Position System(GPS) and Position and Orientation(POS) of Inertial Measurement System(IMU) are combined and used as measurement tools to monitor the beach topography. Image feature point can be matched out and point location (PL) of relative sand topography can be achieved through image technology of aero photogrammetry and aero triangulations methods, then coordinating with Virtual Base Station RTK (VBS-RTK) and Ground Control Point(GCP) to survey coordinates and to correct actual coordinates for achieving PL of actual sand topography and further comparing the terrain variance between the image matching point cloud and direct results of measurements. The results showed that the ground resolution(GSD) is 3.26cm, the average elevation error is with 3.20m, RMSE is with 0.169m, and the correlation index is 0.990 at the place with flight height of 70 meters,which is in accordance with the certification standard of ±25 cm difference of elevation stipulated in relative laws and regulations of Water Resources Agency. The results of this research serve to improve the efficiency of traditional artificial sampling and reduce the cost of using indirect surveying observation, achieving the reduction of error problems in measurements and measurement cost saving.

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Msibi, Senzo Ginious, and 畢申爍. "Slope instability investigation using multi temporal data from conventional photogrammetry and UAV photogrammetry." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/twv98v.

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碩士
國立臺北科技大學
資源工程研究所
107
Every year landslides pose a significant hazard to the lives of people through loss of life and destruction of property. In the last decades, there has been a significant increase in landslide frequency, in concomitance to climate change and the expansion of urbanized areas. Remote sensing techniques with the incorporation of Unmanned Aerial Vehicle (UAV) photography present a powerful tool for landslide investigation. Our main aim was to use multi temporal data from conventional photogrammetry and UAV photogrammetry to investigate slope instability and impact factors. Our focus study area is in Taitung County, Haiduan Township along the Southern Cross-Island Highway number 20 with the main focus section being the slopes on both sides of the river from Wulu Bridge to Lidao Village. In this study, we used aerial images obtained from the Aerial Survey Office, Forest Bureau. From these images we, produced 3D stereo models, orthophotos and digital terrain models (DTMs). We also employed UAV photography to produce a high resolution (5.17 cm) orthophoto and a DTM to help in investigating the evolution of the slope instability and characterization. The visual analysis of the three dimensional (3D) stereo models and orthophotos, profiles cut along the principal sliding direction of the unstable slopes and DTM differencing are discussed in this study as means of investigating the slope instability evolution. Our data analysis, revealed the importance of taking note of resolution during the course of DTM differencing, because the resolution of the output is decided by the relatively low resolution data. From the analysis of our results we were able to discuss the mechanism of the slope instability and influence factors which were summarized as erosion of the slope by the river and gullies running down the slope in zone 1 and 2; gravity is also one of the impact factors which is evident by the slow movement of the slope; lithology of the rock mass; faults and heavy rainfall. The experience gained in this study can be very useful in future studies of slope instability investigations.

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WANG, YEN-CHIEH, and 王彥杰. "Discussion on Accuracy Analysis of UAV Unconventional Photogrammetry." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/98922967043819036419.

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碩士
逢甲大學
都市計畫與空間資訊學系
105
Taiwan's disaster has become increasingly frequent, from a single disaster into a complex disaster, regional planning, analysis depends on the basic information of the knowledge and master, quickly grasp the target information as an important factor in the analysis of Taiwan's changing climate, monitoring information Need to be updated instantly. In the past, it is necessary to rely on the local survey and aeronautical aids. It depends on the influence of equipment and weather. It can’t obtain immediate surface information immediately. The unmanned aerial vehicle has the advantages of high maneuverability, high timeliness and less weather conditions. Advantages, images can also be used with existing maps, such as topographic maps, aerial photographs and satellite imagery and other applications such as stacking, etc., can be a short time to understand the current situation, but also to simplify the required manpower, complete the car can’t reach The current situation of the investigation. Using unmanned aerial vehicle for unconventional photogrammetry, in the area can’t reach the image capture, to explore its shooting accuracy, can achieve the desired results. In this part, the use of consumer unmanned vehicle, in the absence of access to ground control points and aerial imagery map analysis, to explore the unmanned flight vehicle shooting small area image, the accuracy of its flat and mountain, according to the study in the ground control points Using the image with its own coordinates, the accuracy of the ground plane accuracy of up to 1 meter, the mountain plane accuracy error of up to 5 meters, adding ground control points for correction and inspection, flat plane accuracy of up to 20cm; mountain area due to control points to obtain difficulties, the use of a small number of control points to get a plane error of 30cm, this study using unmanned vehicles to obtain the image, the geometric correction can reach 1/5000 of the use of the map.

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Chiang, Chao-Jung, and 江昭蓉. "UAV photogrammetry for topographic monitoring of Jibei-spit." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/v8cd57.

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碩士
國立彰化師範大學
地理學系
106
Coastal areas are highly dynamic and sensitive, vulnerable to the coastal processes and other natural and human-induced causes. It is fundamental to monitor the evolution of coastal landscape and to understand their dynamic and complex of coastal geomorphological system. The advances in unmanned aerial vehicles (UAV) and photogrammetry provide an effective approach to produce accurate, high spatiotemporal resolution DTMs. In this study, we used UAV photogrammetry to survey the topography change in the Jebel Spit in Penghu, the largest spit landscape in Taiwan. The survey was taken at June 2017, August 2017, and May 2018. We used the Pix4Dmapper, a photogrammetry software, to generate high resolutions DSMs. By comparing the DSMs and sampling the grain size of the spit, we illustrated the topography change spatial-temporal aspects and its linkage to the wave and tidal processes. The results show that the optimum accuracies of DSMs were 1 cm and 2 cm in horizontal and vertical directions, respectively, and have ground resolution of 0.8 cm. By comparing the DSMS the topography has 41.1cm of deposition during typhoon season and has 40.9 cm of erosion during northeast monsoon season. Beach surface shows an annually mass balance between the deponition of typhoon and ersion of northeast monsoon. Northeast monsoon plays an erosive role in the intrusion and sedimentation of the spit, and is closely linked to the change of the monsoon direction, the direction of the dominant sediment transport and the surrounding shore platform. As a whole, the UAV photogrammetry can effectively monitor the coastal topographical changes, and the use of high spatial resolution DSM and orthophoto can help understand the changing characteristics of coastal micro-topography.

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Dissertations / Theses on the topic 'UAVs photogrammetry'

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