Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2008. / A rapid measurement system is implemented using two digital video cameras, presenting a faster and less expensive solution to certain metrology problems. The cameras are calibrated from one stereo image-pair of a 3D calibration grid that allows an immediate assessment of the achievable metric accuracy of the system. Three different methods, using either laser tracking or structured light patterns, were developed and employed to solve the coordinate extraction and correspondence matching problems. Different image processing techniques were used to speed up the entire measurement process. All software development was accomplished using only freely distributed software packages. The system achieves calibration in less than a minute and accumulates point correspondences at 12 frames per second. Accuracies of greater than 0.4 mm are achieved for a 235 x 190 x 95 mm measurement volume using a single pair of images with 640 x 480 pixel resolution each.

Indiana University-Purdue University Indianapolis (IUPUI) / Surveillance videos are recorded continually and the retrieval of such videos currently still relies on human operators. Automatic retrieval has not reached a satisfactory accuracy. As an intermediate representation, this work develops multiple original temporal profiles of video to convey accurate temporal information in the video while keeping certain spatial characteristics. These are effective methods to visualizes surveillance video contents efficiently in a 2D temporal image, suitable for indexing and retrieving a large video database. We are aiming to provide a compact index that is intuitive and preserves most of the information in the video in order to avoid browsing extensive video clips frame by frame. By considering some of the properties of static surveillance videos, we aim at accentuating the temporal dimension in our visualization. We have introduced our framework as three unique methods that visualize different aspects of a surveillance video, plus an extension to non-static surveillance videos. In our first method "Localized Temporal Profile", by knowing that most surveillance videos are monitoring specific locations, we try to emphasize the other dimension, time, in our solution. we focus on describing all the events only in critical locations of the video. In our next method "Multi-Position Temporal Profile", we generate an all-inclusive profile that covers all the events in the video field of view. In our last method "Motion Temporal Profile" we perform in-depth analysis of scene motion and try to handle targets with non-uniform, non-translational motion in our temporal profile. We then further extend our framework by loosening the constraint that the video is static and including cameras with smooth panning motion as such videos are widely used in practice. By performing motion analysis on the camera, we stabilize the camera to create a panorama-like effect for the video, allowing us to utilize all of the aforementioned methods. The resulting profiles allows temporal indexing to each video frame, and contains all spatial information in a continuous manner. It also shows the actions and progress of events in the temporal profile. Flexible browsing and effective manipulation of videos can be achieved using the resulting video profiles.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007. / The work presented in this Thesis relates to the increased capabilities of the mobile Internet and the possible use of cellphones as an enhancement to video surveillance systems. The focus of the Thesis is on the delivery of live video content to Java enabled cellphones. The various characteristics, capabilities and limitations of the mobile networks- and phones are investigated. Various options for streaming video content to cellphones are also explored. The design and implementation of a digital surveillance system with the ability to stream live video to a cellphone is presented. Two versions of the streaming protocol are developed and implemented in cellphone applications, with which the video stream can be viewed. An evaluation and real-life testing of the applications are presented. Recommendations regarding further enhancements are provided.

In digital video compression, apart from storage, successful transmission of the compressed video data over the bandwidth limited erroneous channels is another important issue. To enable a video codec for broadcasting application, it is required to implement the corresponding coding tools (e.g. error-resilient coding, rate control etc.). They are normally non-normative parts of a video codec and hence their specifications are not defined in the standard. In Dirac as well, the original codec is optimized for storage purpose only and so, several non-normative part of the encoding tools are still required in order to be able to use in other types of application. Being the "Research and Developments of the Dirac Video Codec" as the research title, phase I of the project is mainly focused on the error-resilient transmission over a noisy channel. The error-resilient coding method used here is a simple and low complex coding scheme which provides the error-resilient transmission of the compressed video bitstream of Dirac video encoder over the packet erasure wired network. The scheme combines source and channel coding approach where error-resilient source coding is achieved by data partitioning in the wavelet transformed domain and channel coding is achieved through the application of either Rate-Compatible Punctured Convolutional (RCPC) Code or Turbo Code (TC) using un-equal error protection between header plus MV and data. The scheme is designed mainly for the packet-erasure channel, i.e. targeted for the Internet broadcasting application. But, for a bandwidth limited channel, it is still required to limit the amount of bits generated from the encoder depending on the available bandwidth in addition to the error-resilient coding. So, in the 2nd phase of the project, a rate control algorithm is presented. The algorithm is based upon the Quality Factor (QF) optimization method where QF of the encoded video is adaptively changing in order to achieve average bitrate which is constant over each Group of Picture (GOP). A relation between the bitrate, R and the QF, which is called Rate-QF (R-QF) model is derived in order to estimate the optimum QF of the current encoding frame for a given target bitrate, R. In some applications like video conferencing, real-time encoding and decoding with minimum delay is crucial, but, the ability to do real-time encoding/decoding is largely determined by the complexity of the encoder/decoder. As we all know that motion estimation process inside the encoder is the most time consuming stage. So, reducing the complexity of the motion estimation stage will certainly give one step closer to the real-time application. So, as a partial contribution toward realtime application, in the final phase of the research, a fast Motion Estimation (ME) strategy is designed and implemented. It is the combination of modified adaptive search plus semi-hierarchical way of motion estimation. The same strategy was implemented in both Dirac and H.264 in order to investigate its performance on different codecs. Together with this fast ME strategy, a method which is called partial cost function calculation in order to further reduce down the computational load of the cost function calculation was presented. The calculation is based upon the pre-defined set of patterns which were chosen in such a way that they have as much maximum coverage as possible over the whole block. In summary, this research work has contributed to the error-resilient transmission of compressed bitstreams of Dirac video encoder over a bandwidth limited error prone channel. In addition to this, the final phase of the research has partially contributed toward the real-time application of the Dirac video codec by implementing a fast motion estimation strategy together with partial cost function calculation idea.

Walk 14 Blocks is a document that describes my two-year investigation of simulation in everyday life. It describes how I examine both simulated places and the tools of simulation. I explain the key elements relating my work to simulation; experience, language, and the video monitor. I trace how I have utilized these elements in several works that led to my thesis exhibition titled Evidence.

A área de Personalização de Conteúdo tem sido foco de pesquisas recentes em Ciências da Computação, sendo a segmentação automática de vídeos digitais em cenas uma linha importante no suporte à composição de serviços de personalização, tais como recomendação ou sumarização de conteúdo. Uma das principais abordagens de segmentação em cenas se baseia no agrupamento de tomadas relacionadas. Logo, para que esse processo seja bem sucedido, é necessário que as tomadas estejam bem representadas. Porém, percebe-se que esse tópico tem sido deixado em segundo plano pelas pesquisas relacionadas à segmentação. Assim, este trabalho tem o objetivo de desenvolver um método baseado nas características visuais dos quadros, que possibilite aprimorar a representação de tomadas de vídeos digitais e, consequentemente, contribuir para a melhoria do desempenho de técnicas de segmentação em cenas. / The Content Personalization area has been the focus of recent researches in Computer Science and the automatic scene segmentation of digital videos is an important field supporting the composition of personalization services, such as content recommendation or summarization. One of the main approaches for scene segmentation is based on the clustering of related shots. Thus, in order to this process to be successful, is necessary to properly represent shots. However, we can see that the works reported on the literature have left this topic in backgroud. Therefore, this work aims to develop a method based on frames visual features, which enables to improve video shots representation and, consequently, the performance of scene segmentation techniques.

Perceptual video coding has been a promising area during the last years. Increases in compression ratios have been reported by applying foveated video coding techniques where the region of interest (ROI) is selected by using a computational attention model. However, most of the approaches for perceptual video coding only use visual features ignoring the auditory component. In recent physiological studies, it has been demonstrated that auditory stimuli affects our visual perception. In this work, we validate some of those physiological tests using complex video sequence. We designed and developed a web-based tool for video quality measurement. After conducting different experiments, we observed that in the general reaction time to detect video artifacts was higher when video was presented with the audio information. We observed that emotional information in audio guide human attention to particular ROI. We also observed that sound frequency change spatial frequency perception in still images. / by Freddy Torres. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

O problema de contagem de pessoas em uma determinada região é de grande importância, e tem várias aplicações, tais como: planejamento dos serviços fornecidos por cinemas, shoppings centers, companhias de ônibus, assim como para o monitoramento do tráfego de pedestres em áreas urbanas. A necessidade de se conceber sistemas confiáveis capazes de contabilizar, em tempo real, o número de pessoas circulando em uma determinada região tem sido evidenciado por essas aplicações. Este trabalho apresenta um sistema de baixo custo para a estimação do fluxo multidirecional de pedestres, em ambientes abertos e não restritos, baseado na seqüência de imagens digitais, capturadas por uma única câmera vídeo tipo WEBCAM. A câmera é colocada na vertical do espaço a ser monitorado e conectada a um PC através da porta USB. A metodologia tem como base o trabalho desenvolvido por Pádua (2002) e utiliza o algoritmo proposto em Lucas e Kanade (1981) que computa o fluxo óptico das imagens capturadas pela câmera. Uma análise espaço-temporal desse fluxo é realizada para determinar o fluxo multidirecional dos pedestres. / The problem in counting people in restricted area is of great importance in planning the services offered by cinemas, malls and bus companies and also for controlling pedestrians traffic in urban areas. These applications have evinced the need for developing reliable real time systems capable of counting pedestrians in regions of interest. This work presents a low cost system for estimating the multidirectional flow of pedestrians in open areas and non-restricted areas. This system has only one WEBCAM placed in a vertical position in the area to be monitored. This camera is connected to the PC computer system through the USB port. The methodology is based in the work developed by Pádua (2002) and in the algorithm proposed by Lucas e Kanade (1981) that computerizes the optical flow of the images acquired by the stationary camera. The multidirectional flow is estimated by the temporal-space analysis of this optical flow

A proliferação de conteúdos estereoscópicos atualmente é uma realidade, devido, principalmente, ao interesse e a percepção de valor do público, em geral, como uma tecnologia amigável. Os diversos benefícios trazidos por essa tecnologia, do entretenimento à pesquisa, influenciaram no desenvolvimento de inúmeras técnicas de captação, codificação e reprodução desses vídeos. Tendo em vista a integração com a infraestrutura atual, novas técnicas continuam surgindo e trazendo novas descobertas. No entanto, no campo da codificação, existe um problema que envolve a dificuldade para reproduzir um vídeo sem se conhecer a técnica de codificação que o gerou. Um ponto comum das formas de reprodução é que todas tomam como base um par estéreo, o que, por um lado pode, genericamente, permitir a codificação para operar em modos de reprodução diferentes, mas, por outro lado, traz outro problema, o de duplicar o volume de dados demandados, tornando-o de alto custo para armazenamento e transmissão. Assim, nesta dissertação foi desenvolvida uma nova técnica para reverter um anáglifo a uma aproximação do par estéreo original baseada em busca local rápida, utilizando apenas nas informações intracodificadas do vídeo anáglifo. A utilização anáglifo e da técnica de reversão, reduz o volume dos dados e torna genérico o conteúdo para reprodução. Para mensurar os resultados, foram realizados experimentos submetidos a análise objetiva utilizando o PSNR (Peak Signal to Noise Ratio) e a análise subjetiva com o método DSCQS (Double Stimulus Continuous Quality Scale). Como resultados foram recuperados aproximações dos pares estéreos originais independentes do modo de visualização com boa qualidade visual e boa percepção de profundidade. / The proliferation of stereoscopic content is currently a reality, mainly due to the public interest and perception of value, in general, as a friendly technology. The diverse benefits brought by this technology, from entertainment to research, have influenced the development of numerous techniques for capturing, coding and reproducing these videos. In view of the integration with the current infrastructure, new techniques continue to emerge and bring new discoveries. However, in the field of coding, there is a problem that involves the difficulty of reproducing a video without knowing the coding technique that generated it. A common point of the forms of reproduction is that all are based on a stereo pair, which, on the one hand, can generically allow coding to operate in different reproduction modes, but on the other hand, it brings another problem, that of duplicate the volume of data demanded, making it costly for storage and transmission. Thus, in this dissertation a new technique was developed to revert an anaglyph to an approximation of the original stereo pair based on fast local search, using only the intracoded information of the anaglyph video. The anaglyph use and reversal technique reduces the volume of data and makes the content for reproduction generic. To measure the results, experiments were performed under objective analysis using PSNR (Peak Signal to Noise Ratio) and subjective analysis with the DSCQS (Double Stimulus Continuous Quality Scale) method. As a result, approximations of the original stereo pairs independent of the viewing mode with good visual quality and good depth perception were retrieved.

by Sze Ho Pong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 50-[53]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Related Work --- p.3 / Chapter 1.2 --- Contributions of the Thesis --- p.3 / Chapter 1.3 --- Organization of the Thesis --- p.4 / Chapter 2 --- Background --- p.5 / Chapter 2.1 --- Best-effort Internet - The Lossy Network --- p.5 / Chapter 2.2 --- Effects of Packet Loss on Streamed Video --- p.7 / Chapter 2.3 --- Loss Recovery Schemes in Video Streaming --- p.8 / Chapter 3 --- Comparison of Two Packet-Loss Detection Schemes --- p.10 / Chapter 3.1 --- Gap Detection (GD) --- p.12 / Chapter 3.2 --- Time-Out (TO) Detection --- p.14 / Chapter 3.3 --- Mathematical Comparison --- p.17 / Chapter 4 --- The Combined Loss-Detection Algorithm --- p.21 / Chapter 4.1 --- System Architecture --- p.22 / Chapter 4.2 --- Loss Detection and Recovery --- p.23 / Chapter 4.2.1 --- Detecting Data Packet Losses Transmitted for First Time --- p.24 / Chapter 4.2.2 --- Detecting Losses of Retransmitted Packet --- p.28 / Chapter 4.3 --- Buffering Techniques --- p.32 / Chapter 4.3.1 --- Determining Packet-Loss Rate in Presentation --- p.33 / Chapter 4.4 --- Mapping Packet-Loss Rate to Degradation of Video Quality --- p.38 / Chapter 5 --- Experimental Results and Analysis --- p.40 / Chapter 5.1 --- Experimental Setup --- p.40 / Chapter 5.2 --- Small Delay Jitter Environment --- p.42 / Chapter 5.3 --- Large Delay Jitter Environment --- p.44 / Chapter 5.3.1 --- Using Low Bit-Rate Stream --- p.44 / Chapter 5.3.2 --- Using High Bit-Rate Stream --- p.44 / Chapter 6 --- Conclusions and Future Work --- p.47 / Chapter 6.1 --- Conclusions --- p.47 / Chapter 6.2 --- Future Work --- p.49 / Bibliography --- p.50