Дисертації з теми "Subjective and Objective Image Quality Assessment"
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Sendjasni, Abderrezzaq. "Objective and subjective quality assessment of 360-degree images." Electronic Thesis or Diss., Poitiers, 2023. http://www.theses.fr/2023POIT2251.
Повний текст джерела360-degree images, a.k.a. omnidirectional images, are in the center of immersive media. With the increase in demands of the latter, mainly thanks to the offered interactive and immersive experience, it is paramount to provide good quality of experience (QoE). This QoE is significantly impacted by the quality of the content. Like any type of visual signal, 360-degree images go through a sequence of processes including encoding, transmission, decoding, and rendering. Each of these processes has the potential to introduce distortions to the content. To improve the QoE, image quality assessment (IQA) is one of the strategies to be followed. This thesis addresses the quality evaluation of 360-degree images from the objective and subjective perspectives. By focusing on the influence of Head Mounted Displays (HMDs) on the perceived quality of 360-degree images, a psycho-visual study is designed and carried out using four different devices. For this purpose, a 360-degree image datasets is created and a panel of observers is involved. The impact of HMDs on the quality ratings is identified and highlighted as an important factor to consider when con- ducting subjective experiments for 360-degree images. From the objective perspective, we first comprehensively benchmarked several convolutional neural network (CNN) models under various configurations. Then, the processing chain of CNN-based 360-IQA is improved at different scales, from input sampling and representation to aggregating quality scores. Based on the observations of the above studies as well as the benchmark, two 360-IQA models based on CNNs are proposed to accurately predict the quality of 360-degree images. The obtained observations and conclusions from the various contributions shall bring insights for assessing the quality of 360-degree images
360-graders bilder, også kjent som rundstrålende bilder, er i sentrum av oppslukende medier. Med økningen i forventninger til sistnevnte, hovedsakelig takket være den aktiverte interaktive og oppslukende opplevelse, er det avgjørende å gi god kvaliteten på opplevelsen (QoE).Denne QoE er betydelig påvirket av kvaliteten på innholdet. Som alle typer visuelle signaler går 360-graders bilder gjennom en sekvens av prosesser, inkludert koding, overføring, dekoding og gjengivelse. Hver av disse prosessene har potensial til å introdusere forvrengninger til innholdet.For å forbedre QoE er vurdering av bildekvalitet (IQA) en av strategiene å følge. Denne oppgaven tar for seg kvalitetsevaluering av 360-graders bilder fra objektive og subjektive perspektiver. Ved å fokusere på påvirkningen av Head Mounted Displays (HMD-er) på den oppfattede kvaliteten til 360-graders bilder, er en psyko-visuell studie designet og utført ved hjelp av fire forskjellige enheter. For dette formålet opprettes et 360-graders bildedatasett og et panel av observatører er involvert. Virkningen av HMD-er på valitetsvurderingene identifiseres og fremheves som en viktig faktor når du utfører subjektive eksperimenter for 360-graders bilder.Fra det objektive perspektivet benchmarket vi først flere konvolusjonelle nevrale nettverk (CNN) under forskjellige konfigurasjoner. Deretter forbedres prosesseringskjeden til CNN-baserte 360-IQA i forskjellige skalaer, fra input-sampling og representasjon til aggregering av kvalitetspoeng. Basert på observasjonene av de ovenfornevnte studiene så vel som benchmark, foreslås to 360-IQA-modeller basert på CNN-er for å nøyaktig forutsi kvaliteten på 360-graders bilder.De innhentede observasjonene og konklusjonene fra de ulike bidragene skal gi innsikt for å vurdere kvaliteten på 360-graders bilder
Zerman, Emin. "Evaluation et analyse de la qualité vidéo à haute gamme dynamique." Electronic Thesis or Diss., Paris, ENST, 2018. http://www.theses.fr/2018ENST0003.
Повний текст джерелаIn the last decade, high dynamic range (HDR) image and video technology gained a lot of attention, especially within the multimedia community. Recent technological advancements made the acquisition, compression, and reproduction of HDR content easier, and that led to the commercialization of HDR displays and popularization of HDR content. In this context, measuring the quality of HDR content plays a fundamental role in improving the content distribution chain as well as individual parts of it, such as compression and display. However, HDR visual quality assessment presents new challenges with respect to the standard dynamic range (SDR) case. The first challenge is the new conditions introduced by the reproduction of HDR content, e.g. the increase in brightness and contrast. Even though accurate reproduction is not necessary for most of the practical cases, accurate estimation of the emitted luminance is necessary for the objective HDR quality assessment metrics. In order to understand the effects of display rendering on the quality perception, an accurate HDR frame reproduction algorithm was developed, and a subjective experiment was conducted to analyze the impact of different display renderings on subjective and objective HDR quality evaluation. Additionally, in order to understand the impact of color with the increased brightness of the HDR displays, the effects of different color spaces on the HDR video compression performance were also analyzed in another subjective study. Another challenge is to estimate the quality of HDR content objectively, using computers and algorithms. In order to address this challenge, the thesis proceeds with the performance evaluation of full-reference (FR) HDR image quality metrics. HDR images have a larger brightness range and higher contrast values. Since most of the image quality metrics are developed for SDR images, they need to be adapted in order to estimate the quality of HDR images. Different adaptation methods were used for SDR metrics, and they were compared with the existing image quality metrics developed exclusively for HDR images. Moreover, we propose a new method for the evaluation of metric discriminability based ona novel classification approach. Motivated by the need to fuse several different quality databases, in the third part of the thesis, we compare subjective quality scores acquired by using different subjective test methodologies. Subjective quality assessment is regarded as the most effective and reliable way of obtaining “ground-truth” quality scores for the selected stimuli, and the obtained mean opinion scores (MOS) are the values to which generally objective metrics are trained to match. In fact, strong discrepancies can easily be notified across databases when different multimedia quality databases are considered. In order to understand the relationship between the quality values acquired using different methodologies, the relationship between MOS values and pairwise comparisons (PC) scaling results were compared. For this purpose, a series of experiments were conducted using double stimulus impairment scale (DSIS) and pairwise comparisons subjective methodologies. We propose to include cross-content comparisons in the PC experiments in order to improve scaling performance and reduce cross-content variance as well as confidence intervals. The scaled PC scores can also be used for subjective multimedia quality assessment scenarios other than HDR
Ševčík, Martin. "Modelování vlastností modelu HVS v Matlabu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217656.
Повний текст джерелаDalasari, Venkata Gopi Krishna, and Sri Krishna Jayanty. "Low Light Video Enhancement along with Objective and Subjective Quality Assessment." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13500.
Повний текст джерелаGuo, Jinjiang. "Contributions to objective and subjective visual quality assessment of 3d models." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI099.
Повний текст джерелаIn computer graphics realm, three-dimensional graphical data, generally represented by triangular meshes, have become commonplace, and are deployed in a variety of application processes (e.g., smoothing, compression, remeshing, simplification, rendering, etc.). However, these processes inevitably introduce artifacts, altering the visual quality of the rendered 3D data. Thus, in order to perceptually drive the processing algorithms, there is an increasing need for efficient and effective subjective and objective visual quality assessments to evaluate and predict the visual artifacts. In this thesis, we first present a comprehensive survey on different sources of artifacts in digital graphics, and current objective and subjective visual quality assessments of the artifacts. Then, we introduce a newly designed subjective quality study based on evaluations of the local visibility of geometric artifacts, in which observers were asked to mark areas of 3D meshes that contain noticeable distortions. The collected perceived distortion maps are used to illustrate several perceptual functionalities of the human visual system (HVS), and serve as ground-truth to evaluate the performances of well-known geometric attributes and metrics for predicting the local visibility of distortions. Our second study aims to evaluate the visual quality of texture mapped 3D model subjectively and objectively. To achieve these goals, we introduced 136 processed models with both geometric and texture distortions, conducted a paired-comparison subjective experiment, and invited 101 subjects to evaluate the visual qualities of the models under two rendering protocols. Driven by the collected subjective opinions, we propose two objective visual quality metrics for textured meshes, relying on the optimal combinations of geometry and texture quality measures. These proposed perceptual metrics outperform their counterparts in term of the correlation with the human judgment
Shahid, Muhammad. "Methods for Objective and Subjective Video Quality Assessment and for Speech Enhancement." Doctoral thesis, Blekinge Tekniska Högskola [bth.se], Faculty of Engineering - Department of Applied Signal Processing, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00603.
Повний текст джерелаKhaustova, Darya. "Objective assessment of stereoscopic video quality of 3DTV." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S021/document.
Повний текст джерелаThe minimum requirement for any 3D (stereoscopic images) system is to guarantee visual comfort of viewers. Visual comfort is one of the three primary perceptual attributes of 3D QoE, which can be linked directly with technical parameters of a 3D system. Therefore, the goal of this thesis is to characterize objectively the impact of these parameters on human perception for stereoscopic quality monitoring. The first part of the thesis investigates whether visual attention of the viewers should be considered when designing an objective 3D quality metrics. First, the visual attention in 2D and 3D is compared using simple test patterns. The conclusions of this first experiment are validated using complex stimuli with crossed and uncrossed disparities. In addition, we explore the impact of visual discomfort caused by excessive disparities on visual attention. The second part of the thesis is dedicated to the design of an objective model of 3D video QoE, which is based on human perceptual thresholds and acceptability level. Additionally we explore the possibility to use the proposed model as a new subjective scale. For the validation of proposed model, subjective experiments with fully controlled still and moving stereoscopic images with different types of view asymmetries are conducted. The performance is evaluated by comparing objective predictions with subjective scores for various levels of view discrepancies which might provoke visual discomfort
Sahu, Amit K. "Objective assessment of image quality (OAIQ) in fluorescence-enhanced optical imaging." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1068.
Повний текст джерелаChintala, Bala Venkata Sai Sundeep. "Objective Perceptual Quality Assessment of JPEG2000 Image Coding Format Over Wireless Channel." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-17785.
Повний текст джерелаReilly, Andrew James. "Uniform framework for the objective assessment and optimisation of radiotherapy image quality." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5589.
Повний текст джерелаAnsari, Yousuf Hameed, and Sohaib Ahmed Siddiqui. "Quality Assessment for HEVC Encoded Videos: Study of Transmission and Encoding Errors." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13656.
Повний текст джерелаGrönborg, Felix, and Otto Ortega. "Evaluation of Methods for Image Analysis with the Purpose of Imitating Subjective Quality Assessment." Thesis, Linköpings universitet, Medie- och Informationsteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-174849.
Повний текст джерелаExamensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska högskolan, Linköpings universitet
Palit, Robin. "Computational Tools and Methods for Objective Assessment of Image Quality in X-Ray CT and SPECT." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/268492.
Повний текст джерелаAxelson, Per-Erik. "Quality Measures of Halftoned Images (A Review)." Thesis, Linköping University, Department of Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1138.
Повний текст джерелаThis study is a thesis for the Master of Science degree in Media Technology and Engineering at the Department of Science and Technology, Linkoping University. It was accomplished from November 2002 to May 2003.
Objective image quality measures play an important role in various image processing applications. In this paper quality measures applied on halftoned images are aimed to be in focus. Digital halftoning is the process of generating a pattern of binary pixels that create the illusion of a continuous- tone image. Algorithms built on this technique produce results of very different quality and characteristics. To evaluate and improve their performance, it is important to have robust and reliable image quality measures. This literature survey is to give a general description in digital halftoning and halftone image quality methods.
Kim, Jae-Seung. "Objective image quality assessment for positron emission tomography : planar (2D) and volumetric (3D) human and model observer studies /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5836.
Повний текст джерелаServetkienė, Vaida. "Gyvenimo kokybės daugiadimensis vertinimas, identifikuojant kritines sritis." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2013~D_20131115_113802-40756.
Повний текст джерелаThe dissertation examines the topical issue of assessment of the quality of life. Scientific literature still does not offer a uniform perception and scientific definition of the quality of life. Every person can provide this concept with his own interpretation, but in science the quality of life must be a concept expressed by means of specific indicators and measured in relation to the welfare of the population in a specific country. The object of research in this dissertation is the assessment of the quality of life. The aim of the dissertation is, upon analysing interdisciplinary scientific approaches to assessment of the quality of life, to develop a multidimensional model of assessment of the quality of life and to identify the critical areas of the quality of life in Lithuania. The author of the dissertation has carried out a comparative analysis of the definition and conceptions of the quality of life and the quality of life assessment methods employed in practice, conceptualised the concept of the quality of life treating it as an object of economic research which reflects the efficiency of the economic policy of the state, identified the key areas of the quality of life, provided a conception of the quality of life and proposed methodological principles for its assessment, developed a multidimensional quality of life assessment model and, by applying the model, evaluated the quality of life of the Lithuanian population in the context of the EU Member States and... [to full text]
Bensaied, Ghaly Rania. "Subjective quality assessment : a study on the grading scales : illustrations for stereoscopic and 2D video content." Thesis, Evry, Institut national des télécommunications, 2018. http://www.theses.fr/2018TELE0013/document.
Повний текст джерелаQuality evaluation is an ever-fascinating field, covering at least a century of research works emerging from psychology, psychophysics, sociology, marketing, medicine… While for visual quality evaluation the IUT recommendations pave the way towards well-configured, consensual evaluation conditions granting reproducibility and comparability of the experimental results, an in-depth analysis of the state-of-the-art studies shows at least three open challenges related to the: (1) the continuous vs. discrete evaluation scales, (2) the statistical distribution of the scores assigned by the observers and (3) the usage of semantic labels on the grading scales. Thus, the present thesis turns these challenges into three research objectives: 1. bridging at the theoretical level the continuous and the discrete scale evaluation procedures and investigating whether the number of the classes on the discrete scales is a criterion meaningful in the results interpretations or just a parameter; studying the theoretical influence of the statistical model of evolution results and of the size of the panel (number of observers) in the accuracy of the results are also targeted; 2. quantifying the bias induced in subjective video quality experiments by the semantic labels (e.g. Excellent, Good, Fair, Poor and Bad) generally associated to the discrete grading scales; 3. designing and deploying an experimental test-bed able to support their precision and statistical relevance. With respect to these objectives, the main contributions are at theoretical, methodological and experimental levels
Sanches, Silvio Ricardo Rodrigues. "Avaliação objetiva de qualidade de segmentação." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-26062014-111553/.
Повний текст джерелаAssessment of video segmentation quality is a problem seldom investigated by the scientific community. Nevertheless, recent studies presented some objective metrics to evaluate algorithms. Such metrics consider different ways in which segmentation errors occur (perceptual factors) and its parameters are adjusted according to the application for which the segmented frames are intended. In this work: i) we demonstrate empirically that the performance of existing metrics changes according to the segmentation algorithm; ii) we developed a subjective method to evaluate segmentation quality; and iii) we contribute with a new objective metric derived on the basis of experiments from subjective method in order to adjust the parameters of two bilayer segmentation algorithms found in the literature when these algorithms are used for compose scenes in Immersive Teleconference environments.
Xiao, Yao. "User perceived video quality modelling on mobile devices for Vp9 and H265 encoders." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/81842/1/Yao_Xiao_Thesis.pdf.
Повний текст джерелаSmith, Kathryn Elizabeth. "THE URGE TO PURGE: AN ECOLOGICAL MOMENTARY ASSESSMENT OF PURGING DISORDER AND BULIMIA NERVOSA." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1416829240.
Повний текст джерелаNouri, Nedia. "Évaluation de la qualité et transmission en temps-réel de vidéos médicales compressées : application à la télé-chirurgie robotisée." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL049N/document.
Повний текст джерелаThe digital revolution in medical environment speeds up development of remote Robotic-Assisted Surgery and consequently the transmission of medical numerical data such as pictures or videos becomes possible. However, medical video transmission requires significant bandwidth and high compression ratios, only accessible with lossy compression. Therefore research effort has been focussed on video compression algorithms such as MPEG2 and H.264. In this work, we are interested in the question of compression thresholds and associated bitrates are coherent with the acceptance level of the quality in the field of medical video. To evaluate compressed medical video quality, we performed a subjective assessment test with a panel of human observers using a DSCQS (Double-Stimuli Continuous Quality Scale) protocol derived from the ITU-R BT-500-11 recommendations. Promising results estimate that 3 Mbits/s could be sufficient (compression ratio aroundthreshold compression level around 90:1 compared to the original 270 Mbits/s) as far as perceived quality is concerned. Otherwise, determining a tolerance to lossy compression has allowed implementation of a platform for real-time transmission over an IP network for surgical videos compressed with the H.264 standard from the University Hospital of Nancy and the school of surgery
Bršel, Boris. "Porovnání objektivních a subjektivních metrik kvality videa pro Ultra HDTV videosekvence." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241052.
Повний текст джерелаOuni, Sonia. "Evaluation de la qualité des images couleur. Application à la recherche & à l'amélioration des images." Thesis, Reims, 2012. http://www.theses.fr/2012REIMS034.
Повний текст джерелаThe research area in the objective quality assessment of the color images has been a renewed interest in recent years. The work is primarily driven by the advent of digital pictures and additional needs in image coding (compression, transmission, recovery, indexing,...). So far the best evaluation is visual (hence subjective) or by psychophysical techniques or by expert evaluation. Therefore, it is useful, even necessary, to establish criteria and objectives that automatically measures quality scores closest possible quality scores given by the subjective evaluation. We propose, firstly, a new full reference metric to assess the quality of color images, called overall Delta E, based on color appearance and incorporates the features of the human visual system (HVS). Performance was measured in two areas of application compression and restoration. The experiments carried out show a significant correlation between the results and subjective assessment.Then, we propose a new no reference quality assessmenent color images approach based on neural networks: given the multidimensional nature of image quality, a quantification of quality has been proposed, based on a set of attributes forming the descriptor UN (Utility, Naturalness). Accuracy reflects the sharpness and clarity. As for naturality, it reflects the brightness and color. To model the criterion of color, three no reference metrics were defined to detect the dominant color in the image, the proportion of that color and its spatial dispersion. This approach is based on neural networks to mimic the HVS perception. Two variants of this approach have been tried (direct and progressive). The results showed the performance of the progressive variant compared to the direct variant. The application of the proposed approach in two areas: in the context of restoration, this approach has served as a stopping criterion for automatic restoration algorithms. In addition, we have used in a system for estimating the quality of images to automatically detect the type of content in an image degradation. In the context of indexing and image retrieval, the proposed approach was used to introduce the quality of images in the database as an index. The experimental results showed the improvement of system performance image search by content by using the index or by making a quality refinement results with the quality criterion
Begazo, Dante Coaquira. "Método de avaliação de qualidade de vídeo por otimização condicionada." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-09032018-152946/.
Повний текст джерелаThis dissertation proposes two objective metrics for estimating human perception of quality for video subject to transmission degradation over packet networks. The first metric just uses traffic data while the second one uses both the degraded and the reference video sequences. That is, the latter is a full reference (FR) metric called Quadratic Combinational Metric (QCM) and the former one is a no reference (NR) metric called Viewing Quality Objective Metric (VQOM). In particular, the design procedure is applied to packet delay variation (PDV) impairments, whose compensation or control is very important to maintain quality. The NR metric is described by a cubic spline composed of two cubic polynomials that meet smoothly at a point called a knot. As the first step in the design of either metric, the spectators score a training set of degraded video sequences. The objective function for designing the NR metric includes the total square error between the scores and their parametric estimates, still regarded as algebraic expressions. In addition, the objective function is augmented by the addition of three equality constraints for the derivatives at the knot, whose position is specified within a fine grid of points between the minimum value and the maximum value of the degradation factor. These constraints are affected by Lagrange multipliers and added to the objective function to obtain the Lagrangian, which is minimized by the suboptimal polynomial coefficients determined as a function of each knot in the grid. Finally, the knot value is selected that yields the minimum square error. By means of the selected knot value, the final values of the polynomial coefficients are determined. On the other hand, the FR metric is a nonlinear combination of two popular metrics, namely, the Peak Signal-to-Noise Ratio (PSNR) and the Structural Similarity Index (SSIM). A complete second-degree two-variable polynomial is used for the combination since it is sensitive to both constituent metrics while avoiding overfitting. In the training phase, the set of values for the coefficients of this polynomial is determined by minimizing the mean square error to the opinions over the training database. Both metrics, the VQOM and the QCM, are trained and validated using one database and tested with a different one. The test results are compared with recent NR and FR metrics by means of correlation coefficients, obtaining favorable results for the proposed metrics.
Hessel, Charles. "La décomposition automatique d'une image en base et détail : Application au rehaussement de contraste." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLN017/document.
Повний текст джерелаIn this CIFRE thesis, a collaboration between the Center of Mathematics and their Applications, École Normale Supérieure de Cachan and the company DxO, we tackle the problem of the additive decomposition of an image into base and detail. Such a decomposition is a fundamental tool in image processing. For applications to professional photo editing in DxO Photolab, a core requirement is the absence of artifacts. For instance, in the context of contrast enhancement, in which the base is reduced and the detail increased, minor artifacts becomes highly visible. The distortions thus introduced are unacceptable from the point of view of a photographer.The objective of this thesis is to single out and study the most suitable filters to perform this task, to improve the best ones and to define new ones. This requires a rigorous measure of the quality of the base plus detail decomposition. We examine two classic artifacts (halo and staircasing) and discover three more sorts that are equally crucial: contrast halo, compartmentalization, and the dark halo. This leads us to construct five adapted patterns to measure these artifacts. We end up ranking the optimal filters based on these measurements, and arrive at a clear decision about the best filters. Two filters stand out, including one we propose
Bednarz, Robin. "Analýza kvality obrazu v digitálních televizních systémech." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217810.
Повний текст джерелаVlad, Raluca Ioana. "Une méthode pour l'évaluation de la qualité des images 3D stéréoscopiques." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00925280.
Повний текст джерелаFriberg, Annika. "Interaktionskvalitet - hur mäts det?" Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20810.
Повний текст джерелаTechnical developments have led to the broadcasting of massive amounts of information, athigh velocities. We must learn to handle this flow. To maximize the benefits of newtechnologies and avoid the problems that this immense information flow brings, interactionquality should be studied. We must adjust interfaces to the user because the user does nothave the ability to adapt and sort overly large amounts of information. We must developsystems that make the human more efficient when using interfaces.To adjust the interfaces to the user needs and limitations, knowledge about humancognitive processes is required. When cognitive workload is studied it is important that aflexible, easily accessed and non assertive technique is used to get unbiased results. At thesame time reliability is of great importance. To design interfaces with high interaction quality,a technique to evaluate these is required. The aim of this paper is to establish a method that iswell suited for measurement of interaction quality.When measuring interaction quality, a combination of subjective and physiologicalmethods is recommended. This comprises a combination of Functional near-infraredspectroscopy; a physiological measurement which measures brain activity using light sourcesand detectors placed on the frontal lobe, Electrodermal activity; a physiological measurementwhich measures brain activity using electrodes placed over the scalp and NASA task loadindex; a subjective, multidimensional measurement based on card sorting and measures theindividual perceived cognitive workload on a continuum scale. Measuring with these methodscan result in an increase in interaction quality in interactive, physical and digital interfaces.An estimation of interaction quality can contribute to eliminate interaction errors, thusimproving the user’s interaction experience.
Bishtawi, Wajih Walid. "Objective measurement of subjective image quality." Thesis, 1996. http://spectrum.library.concordia.ca/3799/1/MM10824.pdf.
Повний текст джерелаWu, Chen-Chi, and 吳楨祺. "Subjective Visual Quality Assessment for Image Retargeting." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/14746718777168515054.
Повний текст джерела國立清華大學
電機工程學系
100
With the development of various technologies in image/video processing applications, it is more convenient to share images/videos on different multimedia devices. However, due to different display screen sizes of multimedia devices, we have to resize images/videos to deliver the image/video data for users. Since image/video retargeting will cause visual information loss or distortion, an evaluation method to assess the performance of image/video retargeting is much desired. In order to evaluate the visual quality of retargeted images/videos, we design a subjective visual quality assessment method to precisely record human subjective perception. Our subjective visual quality assessment method includes three parts. First, we ask participants to make an overall image subjective visual quality voting. Then, we let participant judge images about the subjective image information loss. Finally, we request participants to choose the subjective reasons for their voting. Through analyzing correlations between the results from the subjective visual quality assessment method and the objective visual quality metric, we verify whether the results from the objective visual quality metric are consistent with those from the subjective visual quality assessment method. Besides, statistical results are used to analyze relations between image attributes, and discuss different types of distortion caused by different image retargeting algorithms.
Yang, Ping-Hui, and 楊炳輝. "Subjective and Objective Assessment of Sleep Quality in College Students." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/83296646845326998385.
Повний текст джерела中臺科技大學
醫學檢驗生物技術系碩士班
102
Background: Poor sleep quality is thought to cause psychological and physical disease. Many college students generally have sleep problems, however, the study of sleep disturbance and sleep behavior for college students are limited. We conduct both subjective and objective evaluation to explore the sleep quality and sleep related problem among college students. Material and methods: The participants included age 18-30 college students. After informed human trails consent, the subjective questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and the snore outcomes survey (SOS) were used in this research. When the participants with the outcomes of PSQI>5, ESS>10 and SOS<55 were assessed using wrist actigraphy, oximeter or polysomnography (PSG). Participants with actigraphy for 7days to record activity and sleep time of 24 hour; with oximeter for 3 days to assess oxygen saturation and heart rate; with PSG for 1-2 days to evaluate the sleep cycle and sleep apnea by determine EEG, EOG, EMG, ECG, flow, thoracoabdominal motion, oxygen saturation, snore and position. Data was analyzed by using Statistical Package of Social Sciences (SPSS) version 12. Results: Nine hundred and twenty-nine students participate in this study and 900 students have completed questionnaires (recovery rate 97%). The outcomes of descriptive statistics revealed BMI index≧24 (18%, n = 161), PSQI>5 (67.11%, n = 604), ESS>10 (33.50%, n = 302) and SOS<55 (2.40%,n = 22), respectively. The results show one half students have poor sleep quality and 20% or more have daytime sleepiness. The significant correlation are between gender, exercise habit, BMI, (p<0.05). One hundred sixty volunteers with actigraphy and oximeter indicate the normal oxygen saturation (96%) and mean bedtime at 01:10 on weekday and average of 459.9 minutes sleep time and 94.2% sleep efficiency. According to PSG determination, 44% students have abnormal levels of Apnea-Hypopnea Index (AHI >5) who were suspected with sleep apnea. Conclusion: Poor sleep quality is significant problem among students in our institution. The results may be related to delayed bedtime, no exercise habits, higher BMI and less napping. In addition, almost 44% students were suspected to have sleep apnea. The results explore the importance and need for investigation of sleep quality of college students. Even it is time-cost and not easy to obtain the subjects, we will still working on gather subjective and objective sleep related parameters. We hope to help young adults to realize personal sleep quality and to prevent the physiological and psychological disease caused by sleep problems.
Li, Qiang. "Objective image and video quality assessment with applications." 2009. http://hdl.handle.net/10106/1640.
Повний текст джерелаGUO, Jinjiang. "Contributions to objective and subjective visual quality assessment of 3d models." Thesis, 2016. http://www.theses.fr/2016LYSEI099/document.
Повний текст джерелаIn computer graphics realm, three-dimensional graphical data, generally represented by triangular meshes, have become commonplace, and are deployed in a variety of application processes (e.g., smoothing, compression, remeshing, simplification, rendering, etc.). However, these processes inevitably introduce artifacts, altering the visual quality of the rendered 3D data. Thus, in order to perceptually drive the processing algorithms, there is an increasing need for efficient and effective subjective and objective visual quality assessments to evaluate and predict the visual artifacts. In this thesis, we first present a comprehensive survey on different sources of artifacts in digital graphics, and current objective and subjective visual quality assessments of the artifacts. Then, we introduce a newly designed subjective quality study based on evaluations of the local visibility of geometric artifacts, in which observers were asked to mark areas of 3D meshes that contain noticeable distortions. The collected perceived distortion maps are used to illustrate several perceptual functionalities of the human visual system (HVS), and serve as ground-truth to evaluate the performances of well-known geometric attributes and metrics for predicting the local visibility of distortions. Our second study aims to evaluate the visual quality of texture mapped 3D model subjectively and objectively. To achieve these goals, we introduced 136 processed models with both geometric and texture distortions, conducted a paired-comparison subjective experiment, and invited 101 subjects to evaluate the visual qualities of the models under two rendering protocols. Driven by the collected subjective opinions, we propose two objective visual quality metrics for textured meshes, relying on the optimal combinations of geometry and texture quality measures. These proposed perceptual metrics outperform their counterparts in term of the correlation with the human judgment
Chang, Chuan, and 張詮. "BJND-based Stereo Image Coding and Objective Quality Assessment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/x4686d.
Повний текст джерела國立中正大學
電機工程研究所
104
3D entertainment device has growing recently, from 3D films to smart phones, stereoscopic video can bring users rights in the scene feeling. However, stereoscopic videos’ data are much larger than 2D’s. To solve this problem, lots of stereoscopic video standards are proposed in succession. Most of them use highly similarity between base view and non base view video to improve coding efficiency. Traditional stereoscopic video coding scheme didn’t consider binocular perceptions caused by the distortion of base view video and non-base view video, respectively. Binocular perceptions includes binocular fusion, binocular rivalry and binocular suppression. Above all, stereoscopic video coding which considers binocular perceptions become more important. To solve the problem of stereoscopic video coding, not only coding scheme has to change, but also objective stereo video quality assessment. The quality of experience of stereoscopic video contains both binocular perceptions and the quality of 2D videos. This paper proposed a stereoscopic image coding scheme and an objective image quality assessment both based on BJND (Binocular Just Noticeable Distortion).,BJND, which was proposed recently, could use to measure binocular perceptions occurred by distorted stereoscopic images. With BJND, we can decide there are binocular redundancies in stereo images. Through erase those redundancies, coding efficiency will be improved and maintain quality of experience at same time. And we also design an objective quality assessment algorithm based on BJND which will has highly correlation between subjective quality and proposed method.
Chen, Chin-Hua, and 陳金徽. "Objective Assessment Index for Radiation Quality of Digital Image." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/94212648782359244144.
Повний текст джерела國立成功大學
地球科學系專班
94
Along with the fast development of the remote sensing sensor and computer technique, the remotely sensed image data is a great deal of is a current obvious trend in the spatial information realm application, the acquired raw image quality and the technique of image processing will affect the image interpretation, automatic classification and the quality of generated ortho-image directly . Therefore, how with objective and the method for nearing to the human vision to carry on the valuation of image quality and have become a meaningful research work. In this study, we will introduce two kinds of new image quality index UQI and SSIM to digital aerial image and high resolution satellite image that are main source of digital mapping area. We uses some image processing techniques that include image enhancement, haze removal , image fusion, image compress and resampling etc. in this related processing and new and traditional each index in concrete study in the applicability of the radiation quality valuation. Through all the computation results, the applicability in two kinds of new index UQI and SSIM is better than traditional of objective valuation index , also to mapping procedure the distinguishing feature of some images processing method gives the confirmation, for example the method of the image fusion , resampling and image compression method etc..
"Full-reference objective visual quality assessment for images and videos." 2012. http://library.cuhk.edu.hk/record=b5549488.
Повний текст джерела該論文主要研究全參考客觀視覺質量度量算法。主要內容分為三部分。
第一部分討論圖像質量評估。首先研究了一個經典的圖像質量度量算法--SSIM。提出了個新的加權方法並整合至IjSSIM 當中,提升了SSIM自可預測精度。之後,受到前面這個工作的故發,設計7 個全新的圖像質量度量算法,將噪聲分類為加性噪聲和細節失兩大類。這個算法在很多主觀質量圓像資料庫上都有很優秀的預測表現。
第二部分研究視頻質量評估。首先,將上面提到的全新的圓像質量度量算法通過挖掘視頻運動信息和時域相關的人眼視覺特性擴展為視頻質量度量算法。方法包括:使用基於人自民運動的時空域對比敏感度方程,使用基於運動崗量的時域視覺掩蓋,使用基於認知層面的空域整合等等。這個算法被證明對處理標清和高清序列同樣有效。其次,提出了一個測量視頻順間不一致程度的算法。該算法被整合到MSE 中,提高了MSE的預測表現。
上面提到的算法只考慮到了亮度噪聲。論文的最後部分通過個具體應用色差立體圓像生成究了色度噪聲。色差立體圖像是三維立體顯示技衛的其中種方法。它使在普通電視、電腦顯示器、甚至印刷品上顯示三維立體效果成為可能。我們提出了一個新的色差立體圖像生成方法。該方法工作在CIELAB彩色空間,並力圖匹配原始圖像與觀測立體圖像的色彩屬性值。
Visual quality assessment (VQA) plays a fundamental role in multimedia applications. Since the human visual system (HVS) is the ultimate viewer of the visual information, subjective VQA is considered to be the most reliable way to evaluate visual quality. However, subjective VQA is time-consuming, expensive, and not feasible for on-line manipulation. Therefore, automatic objective VQA algorithms, or namely visual quality metrics, have been developed and widely used in practical applications. However, it is well known that the popular visual quality metrics, such as Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), etc., correlate poorly with the human perception of visual quality. The development of more accurate objective VQA algorithms becomes of paramount importance to the future visual information processing and communication applications.
In this thesis, full-reference objective VQA algorithms are investigated. Three parts of the work are discussed as briefly summarized below.
The first part concerns image quality assessment. It starts with the investigation of a popular image quality metric, i.e., Structural Similarity Index (SSIM). A novel weighting function is proposed and incorporated into SSIM, which leads to a substantial performance improvement in terms of matching subjective ratings. Inspired by this work, a novel image quality metric is developed by separately evaluating two distinct types of spatial distortions: detail losses and additive impairments. The pro- posed method demonstrates the state-of-the-art predictive performance on most of the publicly-available subjective quality image databases.
The second part investigates video quality assessment. We extend the proposed image quality metric to assess video quality by exploiting motion information and temporal HVS characteristics, e.g., eye movement spatio-velocity contrast sensitivity function, temporal masking using motion vectors, temporal pooling considering human cognitive behaviors, etc. It has been experimentally verified that the proposed video quality metric can achieve good performance on both standard-definition and high-definition video databases. We also propose a novel method to measure temporal inconsistency, an essential type of video temporal distortions. It is incorporated into the MSE for video quality assessment, and experiments show that it can significantly enhance MSE's predictive performance.
The aforementioned algorithms only analyze luminance distortions. In the last part, we investigate chrominance distortions for a specific application: anaglyph image generation. Anaglyph image is one of the 3D displaying techniques, which enables stereoscopic perception on traditional TVs, PC monitors, projectors, and even papers. Three perceptual color attributes are taken into account for the color distortion measure, i.e., lightness, saturation, and hue, based on which a novel anaglyph image generation algorithm is developed via approximation in the CIELAB color space.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Li, Songnan.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 122-130).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
Dedication --- p.ii
Acknowledgments --- p.iii
Abstract --- p.vi
Publications --- p.viii
Nomenclature --- p.xii
Contents --- p.xvii
List of Figures --- p.xx
List of Tables --- p.xxii
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Motivation and Objectives --- p.1
Chapter 1.2 --- Overview of Subjective Visual Quality Assessment --- p.3
Chapter 1.2.1 --- Viewing condition --- p.4
Chapter 1.2.2 --- Candidate observer selection --- p.4
Chapter 1.2.3 --- Test sequence selection --- p.4
Chapter 1.2.4 --- Structure of test session --- p.5
Chapter 1.2.5 --- Assessment procedure --- p.6
Chapter 1.2.6 --- Post-processing of scores --- p.7
Chapter 1.3 --- Overview of Objective Visual Quality Assessment --- p.8
Chapter 1.3.1 --- Classification --- p.8
Chapter 1.3.2 --- HVS-model-based metrics --- p.9
Chapter 1.3.3 --- Engineering-based metrics --- p.21
Chapter 1.3.4 --- Performance evaluation method --- p.28
Chapter 1.4 --- Thesis Outline --- p.29
Chapter I --- Image Quality Assessment --- p.32
Chapter 2 --- Weighted Structural Similarity Index based on Local Smoothness --- p.33
Chapter 2.1 --- Introduction --- p.33
Chapter 2.2 --- The Structural Similarity Index --- p.33
Chapter 2.3 --- Influence of the Smooth Region on SSIM --- p.35
Chapter 2.3.1 --- Overall performance analysis --- p.35
Chapter 2.3.2 --- Performance analysis for individual distortion types --- p.37
Chapter 2.4 --- The Proposed Weighted-SSIM --- p.40
Chapter 2.5 --- Experiments --- p.41
Chapter 2.6 --- Summary --- p.43
Chapter 3 --- Image Quality Assessment by Decoupling Detail Losses and Additive Impairments --- p.44
Chapter 3.1 --- Introduction --- p.44
Chapter 3.2 --- Motivation --- p.45
Chapter 3.3 --- Related Works --- p.47
Chapter 3.4 --- The Proposed Method --- p.48
Chapter 3.4.1 --- Decoupling additive impairments and useful image contents --- p.48
Chapter 3.4.2 --- Simulating the HVS processing --- p.56
Chapter 3.4.3 --- Two quality measures and their combination --- p.58
Chapter 3.5 --- Experiments --- p.59
Chapter 3.5.1 --- Subjective quality image databases --- p.59
Chapter 3.5.2 --- Parameterization --- p.60
Chapter 3.5.3 --- Overall performance --- p.61
Chapter 3.5.4 --- Statistical significance --- p.62
Chapter 3.5.5 --- Performance on individual distortion types --- p.64
Chapter 3.5.6 --- Hypotheses validation --- p.66
Chapter 3.5.7 --- Complexity analysis --- p.69
Chapter 3.6 --- Summary --- p.70
Chapter II --- Video Quality Assessment --- p.71
Chapter 4 --- Video Quality Assessment by Decoupling Detail Losses and Additive Impairments --- p.72
Chapter 4.1 --- Introduction --- p.72
Chapter 4.2 --- Related Works --- p.73
Chapter 4.3 --- The Proposed Method --- p.74
Chapter 4.3.1 --- Framework --- p.74
Chapter 4.3.2 --- Decoupling additive impairments and useful image contents --- p.75
Chapter 4.3.3 --- Motion estimation --- p.76
Chapter 4.3.4 --- Spatio-velocity contrast sensitivity function --- p.77
Chapter 4.3.5 --- Spatial and temporal masking --- p.79
Chapter 4.3.6 --- Two quality measures and their combination --- p.80
Chapter 4.3.7 --- Temporal pooling --- p.81
Chapter 4.4 --- Experiments --- p.82
Chapter 4.4.1 --- Subjective quality video databases --- p.82
Chapter 4.4.2 --- Parameterization --- p.83
Chapter 4.4.3 --- With/without decoupling --- p.84
Chapter 4.4.4 --- Overall predictive performance --- p.85
Chapter 4.4.5 --- Performance on individual distortion types --- p.88
Chapter 4.4.6 --- Cross-distortion performance evaluation --- p.89
Chapter 4.5 --- Summary --- p.91
Chapter 5 --- Temporal Inconsistency Measure --- p.92
Chapter 5.1 --- Introduction --- p.92
Chapter 5.2 --- The Proposed Method --- p.93
Chapter 5.2.1 --- Implementation --- p.93
Chapter 5.2.2 --- MSE TIM --- p.94
Chapter 5.3 --- Experiments --- p.96
Chapter 5.4 --- Summary --- p.97
Chapter III --- Application related to Color and 3D Perception --- p.98
Chapter 6 --- Anaglyph Image Generation --- p.99
Chapter 6.1 --- Introduction --- p.99
Chapter 6.2 --- Anaglyph Image Artifacts --- p.99
Chapter 6.3 --- Related Works --- p.101
Chapter 6.3.1 --- Simple anaglyphs --- p.101
Chapter 6.3.2 --- XYZ and LAB anaglyphs --- p.102
Chapter 6.3.3 --- Ghosting reduction methods --- p.103
Chapter 6.4 --- The Proposed Method --- p.104
Chapter 6.4.1 --- Gamma transfer --- p.104
Chapter 6.4.2 --- Converting RGB to CIELAB --- p.105
Chapter 6.4.3 --- Matching color appearance attributes in CIELAB color space --- p.106
Chapter 6.4.4 --- Converting CIELAB to RGB --- p.110
Chapter 6.4.5 --- Parameterization --- p.111
Chapter 6.5 --- Experiments --- p.112
Chapter 6.5.1 --- Subjective tests --- p.112
Chapter 6.5.2 --- Results and analysis --- p.113
Chapter 6.5.3 --- Complexity --- p.115
Chapter 6.6 --- Summary --- p.115
Chapter 7 --- Conclusions --- p.117
Chapter 7.1 --- Contributions of the Thesis --- p.117
Chapter 7.2 --- Future Research Directions --- p.120
Bibliography --- p.122
Moorthy, Anush Krishna 1986. "Natural scene statistics based blind image quality assessment and repair." Thesis, 2012. http://hdl.handle.net/2152/ETD-UT-2012-05-4965.
Повний текст джерелаtext
Ma, Kede. "Objective Quality Assessment and Optimization for High Dynamic Range Image Tone Mapping." Thesis, 2014. http://hdl.handle.net/10012/8517.
Повний текст джерелаElgström, Henrik. "Assessment of image quality in x-ray fluoroscopy based on Model observers as an objective measure for quality control and image optimization." Thesis, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-158081.
Повний текст джерелаLorsakul, Auranuch. "Objective Assessment of Image Quality: Extension of Numerical Observer Models to Multidimensional Medical Imaging Studies." Thesis, 2015. https://doi.org/10.7916/D8Z60NB4.
Повний текст джерелаGislason-Lee, Amber J., A. Kumcu, S. M. Kengyelics, D. S. Brettle, L. A. Treadgold, M. Sivananthan, and A. G. Davies. "How much image noise can be added in cardiac x-ray imaging without loss in perceived image quality?" 2015. http://hdl.handle.net/10454/16978.
Повний текст джерелаCardiologists use x-ray image sequences of the moving heart acquired in real-time to diagnose and treat cardiac patients. The amount of radiation used is proportional to image quality; however, exposure to radiation is damaging to patients and personnel. The amount by which radiation dose can be reduced without compromising patient care was determined. For five patient image sequences, increments of computer-generated quantum noise (white + colored) were added to the images, frame by frame using pixel-to-pixel addition, to simulate corresponding increments of dose reduction. The noise adding software was calibrated for settings used in cardiac procedures, and validated using standard objective and subjective image quality measurements. The degraded images were viewed next to corresponding original (not degraded) images in a two-alternativeforced- choice staircase psychophysics experiment. Seven cardiologists and five radiographers selected their preferred image based on visualization of the coronary arteries. The point of subjective equality, i.e., level of degradation where the observer could not perceive a difference between the original and degraded images, was calculated; for all patients the median was 33% 15% dose reduction. This demonstrates that a 33% 15% increase in image noise is feasible without being perceived, indicating potential for 33% 15% dose reduction without compromising patient care.
Funded in part by Philips Healthcare, the Netherlands. Part of this work has been performed in the project PANORAMA, co-funded by grants from Belgium, Italy, France, the Netherlands, and the United Kingdom, and the ENIAC Joint Undertaking.
Tseng, Chao-Ching, and 曾昭清. "Research on Supplier Assessment, Quality Improvement and Credibility of Subjective and Objective Scoring Schemes – Taking Taiwan\'s Passive Components as an Example." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/qxrq8f.
Повний текст джерела國立彰化師範大學
企業管理學系
107
ABSTRACT This research, using evaluation and assessment provided by appropriate suppliers, ensures the data to become more transparent and closer to reality through the assessment and evaluation process management. Even under the circumstances of having more subjective than objective observations, more information still can be distilled from original data. This study will use a passive component company as a case. In regards to the supplier evaluation method, there are nine sub-evaluation indicators. All of aforementioned indicators add up to 100% and will be assessed and explored both subjectively and objectively. In order to effectively establish a monitoring mechanism for a supplier evaluation and find possible anomalies (i.e. over- or under-estimations), we will use K-Means method to target the evaluations of A and B factories from the first quarter of 2017 to the first quarter of 2018 by comparing the original evaluation result with that of the K-Means method categorized into three probable outcomes (i.e. A, B, and C). Grades A, B, and C that belong to qualified suppliers represent a score of 95 points and more, a score of 90 but below 95 points, and a score of 85 but below 90 points, respectively. We hope to find and address the problem through this study, as well as establish a set of objective evaluations to increase quality and ensure consistent supply in the long run.
GIANNITRAPANI, PAOLO. "Study of the subjective effects of blur on the vision of natural images: an abstract, physical parametric model for Image Quality Assessment." Doctoral thesis, 2022. http://hdl.handle.net/11573/1637467.
Повний текст джерелаKumcu, A., L. Platisa, H. Chen, Amber J. Gislason-Lee, A. G. Davies, P. Schelkens, Y. Taeymans, and W. Philips. "Selecting stimuli parameters for video quality studies based on perceptual similarity distances." 2015. http://hdl.handle.net/10454/16977.
Повний текст джерелаThis work presents a methodology to optimize the selection of multiple parameter levels of an image acquisition, degradation, or post-processing process applied to stimuli intended to be used in a subjective image or video quality assessment (QA) study. It is known that processing parameters (e.g. compression bit-rate) or techni- cal quality measures (e.g. peak signal-to-noise ratio, PSNR) are often non-linearly related to human quality judgment, and the model of either relationship may not be known in advance. Using these approaches to select parameter levels may lead to an inaccurate estimate of the relationship between the parameter and subjective quality judgments – the system’s quality model. To overcome this, we propose a method for modeling the rela- tionship between parameter levels and perceived quality distances using a paired comparison parameter selection procedure in which subjects judge the perceived similarity in quality. Our goal is to enable the selection of evenly sampled parameter levels within the considered quality range for use in a subjective QA study. This approach is tested on two applications: (1) selection of compression levels for laparoscopic surgery video QA study, and (2) selection of dose levels for an interventional X-ray QA study. Subjective scores, obtained from the follow-up single stimulus QA experiments conducted with expert subjects who evaluated the selected bit-rates and dose levels, were roughly equidistant in the perceptual quality space - as intended. These results suggest that a similarity judgment task can help select parameter values corresponding to desired subjective quality levels.
Parts of this work were performed within the Telesurgery project (co-funded by iMinds, a digital research institute founded by the Flemish Government; project partners are Unilabs Teleradiology, SDNsquare and Barco, with project support from IWT) and the PANORAMA project (co-funded by grants from Belgium, Italy, France, the Netherlands, the United Kingdom, and the ENIAC Joint Undertaking).
"New Signal Processing Methods for Blur Detection and Applications." Doctoral diss., 2019. http://hdl.handle.net/2286/R.I.54945.
Повний текст джерелаDissertation/Thesis
Doctoral Dissertation Electrical Engineering 2019
Duarte, Carlos Rafael Lopes. "Avaliação de Qualidade de Nuvens de Pontos baseada em Aprendizagem Profunda." Master's thesis, 2019. http://hdl.handle.net/10316/87990.
Повний текст джерелаA tecnologia de Nuvens de Pontos tem sido uma das mais promissoras e mais exploradas no que toca à representação de objetos e mapeamento 3D. No entanto a avaliação de qualidade visual deste tipo de conteúdos ainda não é considerada satisfatória. Esta dissertação propõe um novo método de Avaliação Objetiva de Qualidade de Nuvens de Pontos baseada em resultados de Avaliação Subjetiva de Qualidade, utilizando Aprendizagem Profunda, particularmente Redes Neuronais Convolucionais. Este trabalho consistiu em retreinar Redes Neuronais Convolucionais pré-treinadas, usando Transfer Learning para prever de forma objetiva a qualidade deste tipo de conteúdos. Para isto foi necessário encontrar formas alternativas de representação de Nuvens de Pontos, particularmente projeções 2D, para que estas, em conjunto com resultados de Avaliação Subjetiva de Qualidade, pudessem ser utilizados para treinar as Redes Neuronais Convolucionais. Por fim, após o treino das redes, foi criado um dataset suplementar de teste para confirmar a validade e qualidade dos resultados. As redes treinadas foram então utilizadas para prever os valores de qualidade para o dataset suplementar. Para os valores preditos pela rede, foram calculados fatores de desempenho que os comparam com os resultados subjetivos considerando estes últimos como referência. Os melhores resultados obtidos para estes conteúdos foram: 0.2601 de Raíz do Erro Médio Quadrático (Root Mean Square Error - RMSE), 0.9822 de Coeficiente de Correlação de Pearson (Pearson Correlation Coefficient - PCC), 0.9137 de Coeficiente de Correlação de Spearman (Spearman’s Rank Order Correlation Coefficient - SROCC) e 0.2778 de Rácio de Outliers (Outlier Ratio - OR). Os resultados obtidos mostram que é possível utilizar Aprendizagem Profunda para avaliar a qualidade visual destes conteúdos, superando os resultados de estado da arte presentes na literatura.
Point Clouds has been one of the most promising and explored technologies regarding 3D object representation and 3D mapping. However, the solutions to automatically evaluate the visual quality of this type of contents are not yet satisfactory. This Master Thesis propose a new methodology for Objective Quality Assessment of Point Clouds based on Subjective Quality Assessment results, using Deep Learning, particularly Convolutional Neural Networks. The goal of this work was to retrain pre-trained Convolutional Neural Networks, using Transfer Learning, to predict the visual quality of this type of contents. For this it was necessary to find new alternative ways to represent Point Clouds to, together with Subjective Quality Assessment results, train the Convolutional Neural Networks. Finally, after training the networks, an additional dataset was created to confirm the quality of the obtained results. The trained networks were used to predict the quality scores for the additional dataset. After this, some performance indexes were computed comparing the predicted scores against the subjective ground truth. The best results to these contents were 0.2601 of Root Mean Square Error (RMSE), 0.9822 of Pearson Correlation Coefficient (PCC), 0.9137 of Spearman’s Rank Order Correlation Coefficient and 0.2778 of Outlier Ratio (OR). The results obtained show that is possible to predict the subjective visual quality of Point Clouds using Deep Learning, particularly CNNs, outperforming state-of-art results.
Filipe, José Nunes dos Santos. "Improved image rendering for focused plenoptic cameras with extended depth-of-field." Master's thesis, 2019. http://hdl.handle.net/10400.8/3891.
Повний текст джерелаVRZALOVÁ, Monika. "Role sestry ve screeningu deprese u seniorů." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-260905.
Повний текст джерела