Dissertations / Theses on the topic 'Remote sensing - video'

Detailed knowledge of suspended sediment concentration and sediment transport rates is one of the most important and, most elusive goals of data collection for studies involving stream channel morphology and water quality monitoring. Reliable, continuous data on the suspended sediment load of streams are virtually nonexistent. Although it is relatively easy to obtain information on the water discharge through an open channel, it is far more difficult to sample the sediment load of a stream. Suspended sediment concentration is highly variable with time, cumbersome and costly to sample even for short duration periods, and largely independent of other stream flow characteristics such as discharge. This study explored the potential of using ground-based multispectral video remote sensing to monitor suspended sediment concentrations. Data were collected during seven sampling episodes at two test sites in northern Arizona. Two different video systems were employed. The Xybion system recorded reflectance data in four bandwidths for three dates while the Bi-spectral system recorded data in two spectral bands for the remaining four episodes. Video imagery was acquired simultaneously with water samples containing suspended sediment. Digital numbers (DNs) for the two and four band imagery were extracted from 5 by 5 pixel arrays and the average value computed. Water samples were analyzed to determine sediment concentration. Relationships between DNs and reflectance were explored through the use of simple and multiple linear and non-linear regression. Models were generated for the best single and multiple band combinations for both the single date and multidate data sets. Correlation coefficients for the models were comparable or superior to similar models generated from orbital and airborne data. The results of the study indicate that the ground-based technique has great promise for providing suspended sediment data of high spatial and temporal resolution to supplement existing measurement techniques. Recommendations for future work to help improve the basic technique are included.

An airborne multispectral video system was used to collect soil spectral data over a four-square mile region in northeastern Arizona. Six multispectral video images were digitized. Using the red and blue bands of each image, an unsupervised classification was performed. Each was referenced to a digitized U.S. Soil Conservation Service map resulting in classification precisions ranging from 0-92.4 percent. Ground radiometric measurements were made to ascertain spectral separability of the soil samples. Soil color was determined to try to relate Munsell value to classification precision. Misclassification of soil map units was unrelated to soil brightness or areal extent of each soil. Rather, features such as slope, boundary complexity, and surface condition was responsible for misclassifications seen in this study. Best classification results occurred when soil mapping units were relatively homogeneous, possessed slight changes in slope, and had a regular surface with smooth and distinct boundaries.

Airborne multispectral video was evaluated as a tool for obtaining urban land cover information for hydrological simulations. Land cover data was obtained for a small urban watershed in Tucson, Arizona using four methods: multispectral aerial video (2 meter and 4 meter pixel resolution), National High Altitude Photography (NHAP), multispectral satellite imagery from Systeme Pour l'Observation de la Terre (SPOT), and by conventional survey. A semi-automated land cover classification produced four classes: vegetation, buildings, pavement, and bare soil. The land cover data from each classification was used as input to a runoff simulation model. Runoff values generate by each simulation were compared to observed runoff. A chi-square goodness-of-fit test indicated that SPOT produced landcover data most similar to the conventional classification. In the curve number model, the SPOT data produced simulated runoff values most similar to observed runoff.

La presente tesi riguarda l’uso dei dati raccolti da una nuova stazione di video monitoraggio, denominata SGS allo scopo di accrescere la conoscenza dei processi idro-morfodinamici caratteristici di una spiaggia sabbiosa naturale tipica della costa Adriatica, in prossimità di un estuario. La stazione è stata installata all’interno del porto di Senigallia e ogni ora registra un video di dieci minuti a 2Hz. In questa tesi, sono stati elaborati i video raccolti dal 2015 al 2017. Le immagini derivanti sono state utilizzate in due differenti analisi: 1) lo studio della capacità di stimare la batimetria applicando il codice cBathy (un algoritmo ampiamente utilizzato per la valutazione della profondità dell’acqua tramite analisi inversa) ai dati ottici provenienti dalla stazione e 2) lo studio della dinamica di un sistema di barre sommerse. La stima della profondità dell’acqua varia, in termini di qualità, in funzione della posizione spaziale e delle condizioni ondose e si è osservata una generale sottostima della profondità in gran parte del dominio. Si è quindi eseguita una dettagliata analisi per comprendere il motivo di tale risultato. La causa principale è stata attribuita al grande angolo presente tra l’asse ottico della telecamera e la direzione di propagazione delle onde incidenti. Dei test sintetici sono stati usati per analizzare più in profondità questo aspetto. La procedura utilizzata può essere applicata anche per il progetto di nuove stazioni di video-monitoraggio. Per quanto riguarda la seconda analisi, le immagini disponibili permettono di ben identificare la complessa variabilità 3D (commutazione e biforcazione) del sistema di barre sommerse, sottolineando la capacità della stazione SGS di monitorare le caratteristiche del fondale dell’area oggetto di studio. Tre principali ordini di barre sono stati identificati in accordo con gli studi precedenti basati su dati raccolti da indagini in situ e la loro migrazione è stata correlata con il clima ondoso. Durante il periodo analizzato, è stata riscontrata una generale stabilità del sistema di barre in risposta a eventi di tempesta con onde provenienti da NNE, mentre è stato osservato un netto movimento delle barre verso il largo durante l’unica tempesta con onde provenienti da ESE. Il diverso comportamento è stato collegato alla diversa orientazione delle onde e alla riflessione delle onde provenienti da ESE dal molo del fiume.
The present thesis concerns the application of the data coming from a new video-monitoring station, called SGS, to improve knowledge of the hydro-morphodynamic processes on a typical natural sandy beach near an estuary along the Adriatic coast (Italy). The SGS station was installed in the Senigallia harbour and collects ten minutes of full-frame images at 2Hz each hour. In this work, the videos of the period 2015-2017 have been post-processed. The elaborated images have been used to perform two different analyses: 1) the study of the capability of the SGS data to estimate the water depth using cBathy (a widely used algorithm for depth-inversion) and 2) the study of the dynamics of a multiple sandbars system. The results of the first analysis varied in quality as a function of the location and wave conditions and a general underestimation of the depth has been found in a large portion of the domain. A detailed debugging analysis was carried out to find the reasons of this poor performance. The main source of error was found to be the large angle between the camera viewing direction and the direction of propagation of the incident waves. A synthetic analysis was performed to analyse in depth this aspect. The synthetic procedure can be applied also to design future shore-based video monitoring stations. With reference to the second analysis, the complex 3D-variability (switching and bifurcation) of the multiple sandbars system has been recognized from the images, this highlighting the capability of the SGS station to monitor the seabed features of the study field. Three orders of bars have been identified, in agreement with previous studies based on data collected by in-situ surveys and their motion has been correlated with the wave climate. In the analysed period, a general stability of the bar system in response to storm events with waves coming from NNE has been found, while a net offshore migration has been observed under the only storm with waves coming from ESE. The different behaviour has been related to the wave direction and to the reflection of the ESE waves off the wall of the nearby river pier.

The goal of this study is to develop a smoke detecting algorithm using digital image processing techniques on multi-spectral (visible & infrared) video. By utilizing principal component analysis (PCA) followed by spatial filtering of principal component images the location of smoke can be accurately identified over a period of exposure time with a given frame capture rate. This result can be further analyzed with consideration of wind factor and fire detection range to determine if a fire is present within a scene. Infrared spectral data is shown to contribute little information concerning the smoke signature. Moreover, finalized processing techniques are focused on the blue spectral band as it is furthest away from the infrared spectral bands and because it experimentally yields the largest footprint in the processed principal component images in comparison to other spectral bands. A frame rate of .5 images/sec (1 image every 2 seconds) is determined to be the maximum such that temporal variance of smoke can be captured. The study also shows eigenvectors corresponding to the principal components that best represent smoke and are valuable indications of smoke temporal signature. Raw video data is taken through rigorous pre-processing schemes to align frames from respective spectral band both spatially and temporally. A multi-paradigm numerical computing program, MATLAB, is used to match the field of view across five spectral bands: Red, Green, Blue, Long-Wave Infrared, and Mid-Wave Infrared. Extracted frames are aligned temporally from key frames throughout the data capture. This alignment allows for more accurate digital processing for smoke signature. v Clustering analysis on RGB and HSV value systems reveal that color alone is not helpful to segment smoke. The feature values of trees and other false positives are shown to be too closely related to features of smoke for in solely one instance in time. A temporal principal component transform on the blue spectral band eliminates static false positives and emphasizes the temporal variance of moving smoke in images with higher order. A threshold adjustment is applied to a blurred blue principal component of non-unity principal component order and smoke results can be finalized using median filtering. These same processing techniques are applied to difference images as a more simple and traditional technique for identifying temporal variance and results are compared.

Video based remote sensing techniques are well suited to collect spatially resolved wave images in the surf zone with breaking waves and dynamic bathymetric changes. An advanced video-based depth inversion method is developed to remotely survey bathymetry in the surf zone. The present method involves image processing of original wave image sequences, wave property estimation based on linear feature extraction from the processed image sequences, and is combined with a nonlinear depth inversion model. The original wave image sequences are processed through video image frame differencing and directional low-pass filtering schemes to remove wave-breaking-induced foam noise having high frequencies in the surf zone. The features of individual crest trajectories are extracted from the processed and rectified image sequences, i.e. processed image cross-shore timestacks, by tracking pixels of high intensity within an interrogation window of a Radon-transform-based line-detection algorithm. The wave celerity is computed using space-time information of the extracted trajectories of individual wave crests in the cross-shore timestack domain. The presented retrieval of nearshore bathymetry from video image sequences is based on a nonlinear depth inversion using the nonlinear shallow water wave theory. The nonlinear wave amplitude dispersion effects at the breaker points are determined by combining the nonlinear shallow water celerity equation with a wave breaker criterion, thereby computing water depths iteratively from the celerity measured from the video data. The water depths estimated at the breaker points present initial bathymetric anchor points. Bathymetric profiles in the surf zone are inverted by calculating wave heights dissipated after wave breaking with a wave dissipation model and wave heights shoaled before wave breaking with a wave shoaling model. The continuous wave amplitude dispersion effects are subtracted from the measured celerity profiles, resulting in nearshore bathymetric profiles. The nonlinear depth inversion derived bathymetric estimates from nearshore imagery match the measured values with a biased mean depth error of about +0.06m in the depth range of 0.1 to 3m. In addition, the wave height estimates by the depth inversion model are comparable to the in-situ measured wave heights with a biased mean wave height error of about +0.14m. The present depth inversion method based on optical remote-sensing supports coastal management, navigation, and amphibious operations.

Les récifs coralliens, environnements emblématiques de la biodiversité mondiale, font face aux défis posés par le changement climatique, l'élévation du niveau de la mer et l'anthropisation côtière croissante. Les plages adossées à ces récifs, en particulier les plages d'arrière-récifs frangeants, restent relativement peu étudiées malgré leur importance écologique et économique. Ce manuscrit relate les travaux de thèse visant à améliorer notre compréhension de l'hydro-morphodynamique de ces plages à différentes échelles temporelles, en utilisant une caméra vidéo (Video Monitoring System, VMS) couplée à une sonde de pression. Le site d'étude, la plage de l'Hermitage, située dans une zone microtidale sur la côte ouest de l'île de La Réunion dans l'océan Indien, est fréquemment exposée aux houles australes et aux événements cycloniques. Cette plage est suivie par DGPS et drone dans le cadre du Système National d'Observation Dynalit (SNO Dynalit) depuis 2014. Les constats depuis 1950 et les observations actuelles montrent une plage fortement érodée, conséquence de plusieurs facteurs anthropiques. Les résultats de ce travail de thèse montrent la pertinence et les limites de la mobilisation d'une telle instrumentation (caméra vidéo et sonde de pression) pour l'étude des plages d'arrière-récif. Une cyclicité saisonnière de la position de la ligne d'eau (ou ligne de rivage), avec un recul de 1,4 m en hiver et une avancée de 0,9 m en été, est observée. En moyenne, le récif atténue 97% des houles incidentes et agit comme un filtre passe-bas. Par ailleurs, une analyse du runup sur l'estran révèle que les ondes de basses fréquences contribuent à 50% à ce phénomène, et le setup à 40%. Notre étude montre le rôle des ondes longues (infragravitaires (IG) et Very Low Frequency (VLF)) dans les phénomènes de submersion mais aussi d'érosion. Ce travail ouvre des perspectives importantes pour la recherche dans ce type d'environnement dans un contexte de changement climatique et d'élévation du niveau de la mer
Coral reefs, iconic environments of global biodiversity, face the challenges of climate change, rising sea levels, and increasing coastal development. Despite their ecological and economic significance, beaches adjacent to these reefs, especially fringing back-reef beaches, have received relatively little attention. This manuscript presents doctoral research aimed at enhancing our understanding of the hydro-morphodynamics of these beaches across various time scales, utilizing a Video Monitoring System (VMS) coupled with a pressure sensor. The study site, Hermitage Beach, situated in a microtidal zone on the western coast of La Réunion in the Indian Ocean, is frequently exposed to southern swells and cyclonic events. Since 2014, this beach has been monitored by Differential Global Positioning System (DGPS) and drone as part of the Dynalit National Observation System (SNO Dynalit). Findings spanning from 1950 to the present highlight a significantly eroded beach, attributed to various anthropogenic factors. The results of this thesis illustrate the relevance and constraints of utilizing such instrumentation (video camera and pressure sensor) for investigating back-reef beaches. Seasonal fluctuations in the waterline position, with a retreat of 1.4 m in winter and an advance of 0.9 m in summer, are observed. On average, the reef attenuates 97% of incoming swells and functions as a low-pass filter. Additionally, an analysis of runup on the foreshore reveals that low-frequency waves contribute 50% to this phenomenon, with water level setup contributing up to 40%. This research underscores the critical role of long waves (infragravity (IG) and Very Low Frequency (VLF)) in both submersion and erosion processes. It sets the stage for further exploration in this environmental context, particularly in light of climate change and rising sea levels

[ES] Las playas son ambientes ecológicos sumamente valiosos donde a lo largo de una frágil franja de transición converge el entorno terrestre y el medio marino. Durante el último siglo, la mejora en la comprensión de los procesos físicos que ocurren en la zona costera se ha convertido en un asunto de máxima importancia. Para abordar una planificación coherente de la gestión costera se requiere tomar en consideración el dinamismo de los diferentes cambios morfológicos que caracterizan estos ambientes a distintas escalas espaciales y temporales. El límite tierra-agua varía en función de la posición del nivel del mar y de la forma del perfil de playa que continuamente queda modelado por las olas incidentes. Intentar modelizar la respuesta de un paisaje tan voluble geomorfológicamente como las playas requiere disponer de múltiples medidas registradas con suficiente precisión para poder reconocer su respuesta frente a la acción de los distintos agentes geomórficos. Para ello resulta esencial disponer de diferentes sistemas de monitorización capaces de registrar de forma sistemática la línea de costa con exactitud y efectividad. Se requieren nuevos métodos y herramientas informáticas que permitan capturar, caracterizar y analizar eficientemente la información con el objeto de obtener indicadores con significación geomorfológica de calidad. En esto radica el objetivo de la presente tesis doctoral, centrándose en el desarrollo de herramientas y procedimientos eficientes para la monitorización costera mediante el uso de imágenes satelitales y fotografías terrestres. El trabajo aporta soluciones de procesamiento de imágenes de satélite y fotogramétricas a científicos, ingenieros y gestores costeros, proporcionando resultados que evidencian la gran utilidad de estas técnicas viables y de bajo coste para la monitorización costera. Mediante ellas se puede convertir información pública existente y de libre acceso (imágenes satelitales, datos de video cámaras o fotografías de la ciudadanía) en datos de alta calidad para el monitoreo de los cambios morfológicos de las playas, y lograr así una consiguiente gestión sostenible de los recursos costeros.
[CAT] Les platges són ambients ecològics summament valuosos on al llarg d'una feble franja de transició convergeix l'entorn terrestre i el medi marí. En l'últim segle, la millora en la comprensió dels processos físics que ocorren en la zona costanera s'ha convertit en un assumpte de màxima importància. Per a abordar una planificació coherent de la gestió costanera es requereix prendre en consideració el dinamisme dels diferents canvis morfològics que caracteritzen aquests ambients a diferents escales espacials i temporals. El límit terra-aigua varia en funció de la posició del nivell del mar i de la forma del perfil de platja que contínuament queda modelat per les ones incidents. Intentar modelitzar la resposta d'un paisatge tan voluble geomorfològicament com les platges requereix disposar de múltiples mesures registrades amb suficient precisió per poder reconèixer la seua resposta enfront de l'acció dels diferents agents geomòrfics. Per tant, resulta essencial disposar de diferents sistemes de monitoratge capaços de registrar de forma sistemàtica la línia de costa amb exactitud i efectivitat. Es requereixen nous mètodes i eines informàtiques que permeten capturar, caracteritzar i analitzar eficientment la informació a fi d'obtindre indicadors amb significació geomorfològica de qualitat. En això radica l'objectiu de la present tesi doctoral, que es centra en el desenvolupament d'eines i procediments eficients per al monitoratge costaner mitjançant l'ús d'imatges de satèl·lit i fotografies terrestres. El treball aporta solucions de processament d'imatges de satèl·lit i fotogramètriques a científics, enginyers, polítics i gestors costaners, proporcionant resultats que evidencien la gran utilitat d'aquestes tècniques factibles i de baix cost per a la monitorització costanera. Mitjançant aquestes es pot convertir informació pública existent i de lliure accés (imatges de satèl·lit, dades de videocàmeres o fotografies de la ciutadania) en dades d'alta qualitat per al monitoratge dels canvis morfològics de les platges, i aconseguir així una consegüent gestió sostenible dels recursos costaners.
[EN] Beaches are extremely valuable ecological spaces where terrestrial and marine environments converge along a fragile transition strip. An improvement in our understanding of the physical processes that occur in the coastal zone has become increasingly important during the last century. To approach a coherent planning of coastal management it is necessary to consider the dynamism of the various morphological changes that characterize these environments at different spatial and temporal scales. The land-water boundary varies according to the sea level and the shape of a beach profile that is continuously modelled by incident waves. Attempting to model the response of a landscape as geomorphologically volatile as beaches requires multiple precise measurements to recognize responses to the actions of various geomorphic agents. It is therefore essential to have monitoring systems capable of systematically recording the shoreline accurately and effectively. New methods and tools are required to efficiently capture, characterize, and analyze information - and so obtain geomorphologically significant indicators. This is the aim of the doctoral thesis, focusing on the development of tools and procedures for coastal monitoring using satellite images and terrestrial photographs. The work brings satellite image processing and photogrammetric solutions to scientists, engineers, and coastal managers by providing results that demonstrate the usefulness of these viable and low-cost techniques. Existing and freely accessible public information (satellite images, video-derived data, or crowd-sourced photographs) can be converted into high quality data for monitoring morphological changes on beaches and thus help achieve a sustainable management of coastal resources.
Agradecer al Ministerio de Educación, Cultura y Deporte del Gobierno de España por la beca predoctoral FPU, y por las ayudas de movilidad concedidas, que han permitido que esta Tesis Doctoral fuera una realidad. También a los proyectos AICO/2015/098 y CGL2015-69906-R financiados respectivamente por la Generalitat Valenciana y por el Ministerio de Economía y Competitividad.
Sánchez García, E. (2019). Photogrammetry and image processing techniques for beach monitoring [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/123956
TESIS

Geographic Information Systems (GIS) and remote sensing technologies were used to identify and describe potential habitat for three species endemic to the Southwestern United States; the Golden-cheeked Warbler (Dendroica chrysoparia), the Black-capped Vireo (Vireo atricapillus), and the Texas kangaroo rat (Dipodomys elator). For each species, the computerized classification of digital satellite imagery was integrated with ancillary spatial information (e.g. soils, geology, and land use) to construct a data base to be used for ecological evaluation as well as habitat protection and management measures.

碩士
國立彰化師範大學
電機工程學系
105
In this thesis, the unmanned vehicle is controlled by using the Android mobile device. It combines the functions of video surveillance and environment sensing. This study uses the LinkIt Smart 7688 Duo development board as the unmanned vehicle control core, and uses App Inventor 2 to design an Android system App. The smart phones and tablet computer are used as a remote vehicle controller to replace the traditional joystick. The system of this study has the advantages of convenience, low cost and multi-function. In wireless communication, control signals and data transmission using Bluetooth technology, video streaming using Wi-Fi technology. In vehicle remote control, in addition to including the basic touch mode, but also to achieve voice mode and acceleration sensing mode. In video surveillance, via a web browser and App the real-time images can be observed. In environmental sensing, this study detects carbon monoxide as an example, and when the concentration of carbon monoxide is too high, the user can know the warning message through the mobile device.

In the form of images and videos, visual content has always attracted considerable interest and attention to itself since the early days of the computer era. Although, due to the high density of information in such contents, it has always been challenging to generate, process and broadcast videos and images. These challenges grew along with the demand for higher quality content and attained the research community's attention to themselves. Even though many works have been done by researchers and engineers in academic and industrial environments, the demand for high-quality content introduces new constraints on the quality, performance (speed) and energy consumption. This thesis focuses on a couple of image and video processing applications and introduces new approaches and tweaks to improve the performance and save resources while keeping the functionality intact. In the first part, we target Interferometric Synthetic Aperture Radar (InSAR), an imaging technique used by satellites to capture the earth's surface. Many algorithms have been developed to extract useful information, such as height and displacement, from such images. However, the sheer size of these images, along with the complexity of most of these algorithms, lead to very long processing time and resource utilization. In this work, we take one of the dominant algorithms used for almost every In-SAR application, Phase Unwrapping, and introduce an approach to gain up to 6.5 times speedups. We evaluated our method on InSAR images taken by the Radarsat-2 sensor and showed its impact on a real-world application. In the second part of this thesis, we look at a prevalent application, video streaming. These days video streaming dominates the internet traffic, so any slight improvement in terms of energy consumption or resource utilization will make a sizable difference. Although the streamers use various encoding techniques, the quality of experience of the clients prevents them from overplaying these techniques. On the other hand, there has been a growing interest in another venture of research which focuses on developing techniques that aim to restore the quality of the videos that have been subjected to compression. Although these techniques are used by many users on the receiver side, the streamers often ignore their capabilities. In our work, we introduce an approach that makes the streamer aware of the capabilities of the receiver and utilizes that awareness to reduce the cost of transmission without compromising the end user's quality of experience. We demonstrated the technique and proved our concept by applying it to the HEVC encoding standard and JCT-VC dataset.
Graduate

Yes
Wireless capsule endoscopy (WCE) has great advantages over traditional endoscopy because it is portable and easy to use, especially in remote monitoring health-services. However, during the WCE process, the large amount of captured video data demands a significant deal of computation to analyze and retrieve informative video frames. In order to facilitate efficient WCE data collection and browsing task, we present a resource- and bandwidth-aware WCE video summarization framework that extracts the representative keyframes of the WCE video contents by removing redundant and non-informative frames. For redundancy elimination, we use Jeffrey-divergence between color histograms and inter-frame Boolean series-based correlation of color channels. To remove non-informative frames, multi-fractal texture features are extracted to assist the classification using an ensemble-based classifier. Owing to the limited WCE resources, it is impossible for the WCE system to perform computationally intensive video summarization tasks. To resolve computational challenges, mobile-cloud architecture is incorporated, which provides resizable computing capacities by adaptively offloading video summarization tasks between the client and the cloud server. The qualitative and quantitative results are encouraging and show that the proposed framework saves information transmission cost and bandwidth, as well as the valuable time of data analysts in browsing remote sensing data.
Supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A2012904).

Beach nourishment is a soft engineering intervention that supplies sand to the shore, to increase the beach recreational area and to decrease coastal vulnerability to erosion. This study presents the preliminary evaluation of nourishment works performed at the high-energy wave-dominated Portuguese coast. The shoreline was adopted as a proxy to study beach evolution in response to nourishment and to wave forcing. To achieve this aim, images collected by a video monitoring system were used. A nourishment calendar was drawn up based on video screening, highlighting the different zones and phases where the works took place. Over the six-month monitoring period, a total amount of 25 video-derived shorelines were detected by both manual and automated procedures on video imagery. Nourishment works, realized in summer, enlarged the emerged beach extension by about 90 m on average. During winter, the shoreline retreated about 50 m due to wave forcing. Spatial analysis showed that the northern beach sector was more vulnerable and subject to erosion, as it is the downdrift side of the groin.