Besides ABT with higher order transform, a transform based template matching is also investigated. A fast method of template matching, called Fast Walsh Search, is developed. This search method has similar accuracy as exhaustive search but significantly lower computation requirement. / In this thesis, the development of simple but efficient order-16 transforms will be shown. Analysis and comparison with existing order-16 transforms have been carried out. The proposed order-16 transforms were integrated to the existing coding standard reference software individually so as to achieve a new ABT system. In the proposed ABT system, order-4, order-8 and order-16 transforms coexist. The selection of the most appropriate transform is based on the rate-distortion performance of these transforms. A remarkable improvement in coding performance is shown in the experiment results. A significant bit rate reduction can be achieved with our proposed ABT system with both subjective and objective qualities remain unchanged. / Prior knowledge of the coefficient distribution is a key to achieve better coding performance. This is very useful in many areas in coding such as rate control, rate distortion optimization, etc. It is also shown that coefficient distribution of predicted residue is closer to Cauchy distribution rather than traditionally expected Laplace distribution. This can effectively improve the existing processing techniques. / Three kinds of order-l 6 orthogonal DCT-like integer transforms are proposed in this thesis. The first one is the simple integer transform, which is expanded from existing order-8 ICT. The second one is the hybrid integer transform from the Dyadic Weighted Walsh Transform (DWWT). It is shown that it has a better performance than simple integer transform. The last one is a recursive transform. Order-2N transform can be derived from order-N one. It is very close to the DCT. This recursive transform can be implemented in two different ways and they are denoted as LLMICT and CSFICT. They have excellent coding performance. These proposed transforms are investigated and are implemented into the reference software of H.264 and AVS. They are also compared with other order-16 orthogonal integer transform. Experimental results show that the proposed transforms give excellent coding performance and ease to compute. / Transform is a very important coding tool in video coding. It decorrelates the pixel data and removes the redundancy among pixels so as to achieve compression. Traditionally, order-S transform is used in video and image coding. Latest video coding standards, such as H.264/AVC, adopt both order-4 and order-8 transforms. The adaptive use of more than one transforms of different sizes is known as Arbitrary Block-size Transform (ABT). Transforms other than order-4 and order-8 can also be used in ABT. It is expected larger transform size such as order-16 will benefit more in video sequences with higher resolutions such as nap and 1a8ap sequences. As a result, order-16 transform is introduced into ABT system. / Fong, Chi Keung. / Adviser: Wai Kuen Cham. / Source: Dissertation Abstracts International, Volume: 73-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Thesis (M.S.)--Rochester Institute of Technology, 2007. / Typescript. Includes bibliographical references (leaves 76-77).

by Lai Chun Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 68-70). / Abstract also in Chinese. / ACKNOWLEDGMENTS --- p.IV / ABSTRACT --- p.v / Chapter Chapter 1 --- Traditional Image and Video Coding --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Fundamental Principle of Compression --- p.1 / Chapter 1.3 --- Entropy - Value of Information --- p.2 / Chapter 1.4 --- Performance Measure --- p.3 / Chapter 1.5 --- Image Coding Overview --- p.4 / Chapter 1.5.1 --- Digital Image Formation --- p.4 / Chapter 1.5.2 --- Needs of Image Compression --- p.4 / Chapter 1.5.3 --- Classification of Image Compression --- p.5 / Chapter 1.5.4 --- Transform Coding --- p.6 / Chapter 1.6 --- Video Coding Overview --- p.8 / Chapter Chapter 2 --- Discrete Wavelets Transform (DWT) and Subband Coding --- p.11 / Chapter 2.1 --- Subband Coding --- p.11 / Chapter 2.1.1 --- Introduction --- p.11 / Chapter 2.1.2 --- Quadrature Mirror Filters (QMFs) --- p.12 / Chapter 2.1.3 --- Subband Coding for Image --- p.13 / Chapter 2.2 --- Discrete Wavelets Transformation (DWT) --- p.15 / Chapter 2.2.1 --- Introduction --- p.15 / Chapter 2.2.2 --- Wavelet Theory --- p.15 / Chapter 2.2.3 --- Comparison Between Fourier Transform and Wavelet Transform --- p.16 / Chapter Chapter 3 --- Non-expansive Symmetric Extension --- p.19 / Chapter 3.1 --- Introduction --- p.19 / Chapter 3.2 --- Types of extension scheme --- p.19 / Chapter 3.3 --- Non-expansive Symmetric Extension and Symmetric Sub-sampling --- p.21 / Chapter Chapter 4 --- Content-based Video Coding in MPEG-4 Purposed Standard --- p.24 / Chapter 4.1 --- Introduction --- p.24 / Chapter 4.2 --- Motivation of the new MPEG-4 standard --- p.25 / Chapter 4.2.1 --- Changes in the production of audio-visual material --- p.25 / Chapter 4.2.2 --- Changes in the consumption of multimedia information --- p.25 / Chapter 4.2.3 --- Reuse of audio-visual material --- p.26 / Chapter 4.2.4 --- Changes in mode of implementation --- p.26 / Chapter 4.3 --- Objective of MPEG-4 standard --- p.27 / Chapter 4.4 --- Technical Description of MPEG-4 --- p.28 / Chapter 4.4.1 --- Overview of MPEG-4 coding system --- p.28 / Chapter 4.4.2 --- Shape Coding --- p.29 / Chapter 4.4.3 --- Shape Adaptive Texture Coding --- p.33 / Chapter 4.4.4 --- Motion Estimation and Compensation (ME/MC) --- p.35 / Chapter Chapter 5 --- Shape Adaptive Wavelet Transformation Coding Scheme (SA WT) --- p.36 / Chapter 5.1 --- Shape Adaptive Wavelet Transformation --- p.36 / Chapter 5.1.1 --- Introduction --- p.36 / Chapter 5.1.2 --- Description of Transformation Scheme --- p.37 / Chapter 5.2 --- Quantization --- p.40 / Chapter 5.3 --- Entropy Coding --- p.42 / Chapter 5.3.1 --- Introduction --- p.42 / Chapter 5.3.2 --- Stack Run Algorithm --- p.42 / Chapter 5.3.3 --- ZeroTree Entropy (ZTE) Coding Algorithm --- p.45 / Chapter 5.4 --- Binary Shape Coding --- p.49 / Chapter Chapter 6 --- Simulation --- p.51 / Chapter 6.1 --- Introduction --- p.51 / Chapter 6.2 --- SSAWT-Stack Run --- p.52 / Chapter 6.3 --- SSAWT-ZTR --- p.53 / Chapter 6.4 --- Simulation Results --- p.55 / Chapter 6.4.1 --- SSAWT - STACK --- p.55 / Chapter 6.4.2 --- SSAWT ´ؤ ZTE --- p.56 / Chapter 6.4.3 --- Comparison Result - Cjpeg and Wave03. --- p.57 / Chapter 6.5 --- Shape Coding Result --- p.61 / Chapter 6.6 --- Analysis --- p.63 / Chapter Chapter 7 --- Conclusion --- p.64 / Appendix A: Image Segmentation --- p.65 / Reference --- p.68

The first part of this thesis studies advanced wavelet transform techniques for scalable still image object coding. In order to adapt to the content of a given signal and obtain more flexible adaptive representation, two advanced wavelet transform techniques, wavelet packet transform and directional wavelet transform, are developed for object-based image coding. Extensive experiments demonstrate that the new wavelet image coding systems perform comparable to or better than state-of-the-art in image compression while possessing some attractive features such as object-based coding functionality and high coding scalability. / The objective of this thesis is to develop an object-based coding framework built upon a family of wavelet coding techniques for a variety of arbitrarily shaped visual object scalable coding applications. Two kinds of arbitrarily shaped visual object scalable coding techniques are investigated in this thesis. One is object-based scalable wavelet still image coding; another is object-based scalable wavelet video coding. / The second part of this thesis investigates various components of object-based scalable wavelet video coding. A generalized 3-D object-based directional threading, which unifies the concepts of temporal motion threading and spatial directional threading, is seamlessly incorporated into 3-D shape-adaptive directional wavelet transform to exploit the spatio-temporal correlation inside the 3-D video object. To improve the computational efficiency of multi-resolution motion estimation (MRME) in shift-invariant wavelet domain, two fast MRME algorithms are proposed for wavelet-based scalable video coding. As demonstrated in the experiments, the proposed 3-D object-based wavelet video coding techniques consistently outperform MPEG-4 and other wavelet-based schemes for coding arbitrarily shaped video object, while providing full spatio-temporal-quality scalability with non-redundant 3-D subband decomposition. / Liu, Yu. / Adviser: King Ngi Ngan. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3693. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 166-173). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Firstly, the characteristics of HD videos are studied quantitatively. The results show that HD videos distinguish from other lower resolution videos by higher spatial correlation and special power spectral density (PSD), mainly distributed along the vertical and horizontal directions. / Secondly, two techniques for HD video coding are developed based on the aforementioned analysis results. To exploit the spatial property, 2D order-16 transforms are proposed to code the higher correlated signals more efficiently. Specially, two series of 2D order-16 integer transforms, named modified integer cosine transform (MICT) and non-orthogonal integer cosine transform (NICT), are studied and developed to provide different trade-offs between the performance and the complexity. Based on the property of special PSD, parametric interpolation filter (PIF) is proposed for motion-compensated prediction (MCP). Not only can PIF track the non-stationary statistics of video signals as the related work shows, but also it represents interpolation filters by parameters instead of individual coefficients, thus solving the conflict of the accuracy of coefficients and the size of side information. The experimental results show the proposed two coding techniques significantly outperform their equivalents in the state-of-the-art international video coding standards. / Thirdly, interlaced HD videos are studied, and to satisfy different delay constraints, two real-time de-interlacing algorithms are proposed specially for H.264 coded videos. They adapt to local activities, according to the syntax element (SE) values. Accuracy analysis is also introduced to deal with the disparity between the SE values and the real motions and textures. The de-interlacers provide better visual quality than the commonly used ones and can de-interlace 1080i sequences in real time on PCs. / Today, High-Definition (HD) videos become more and more popular with many applications. This thesis analyzes the characteristics of HD videos and develops the appropriate coding and processing techniques accordingly for hybrid video coding. / Dong, Jie. / Adviser: King Ngi Ngan. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 153-158). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Efficient and effective vision systems are proposed in this work for object detection for ground&aerial robots venturing into unknown environments with minimum vision aids, i.e. a single camera. The first problem attempted is that of object search and identification in a situation similar to a disaster site. Based on image analysis, typical pixel-based characteristics of a visual marker have been established to search for, using a block based search algorithm, along with a noise and interference filter. The proposed algorithm has been successfully utilized for the International Aerial Robotics competition 2009. The second problem deals with object detection for collision avoidance in 3D environments. It has been shown that a 3D model of the scene can be generated from 2D image information from a single camera flying through a very small arc of lateral flight around the object, without the need of capturing images from all sides. The forward flight simulations show that the depth extracted from forward motion is usable for large part of the image. After analyzing various constraints associated with this and other existing approaches, Motion Estimation has been proposed. Implementation of motion estimation on videos from onboard cameras resulted in various undesirable and noisy vectors. An in depth analysis of such vectors is presented and solutions are proposed and implemented, demonstrating desirable motion estimation for collision avoidance task.

Après l'entrée dans l'ère du numérique, la consommation vidéo a évolué définissant de nouvelles tendances. Les contenus vidéo sont désormais accessibles sur de nombreuses plateformes (télévision, ordinateur, tablette, smartphone ... ) et par de nombreux moyens, comme les réseaux mobiles, les réseaux satellites, les réseaux terrestres, Internet ou le stockage Blu-ray par exemple. Parallèlement, l'expérience utilisateur s'améliore grâce à la définition de nouveaux formats comme l'Ultra Haute Définition (UHD), le « High Dynamic Range » (HDR) ou le « High Frame Rate » (HFR). Ces formats considèrent une augmentation respectivement de la résolution, de la dynamique des couleurs et de la fréquence d'image. Les nouvelles tendances de consommation et les améliorations des formats imposent de nouvelles contraintes auxquelles doivent répondre les codeurs vidéo actuels et futurs. Dans ce contexte, nous proposons une solution de codage vidéo permettant de répondre à des contraintes de codage multi-formats, multi-destinations, rapide et efficace en termes de compression. Cette solution s'appuie sur l'extension Scalable du standard de compression vidéo « High Efficiency Video Coding » (HEVC) définie en fin d'année 2014, aussi appelée SHVC. Elle permet de réaliser des codages scalables en produisant un unique bitstream à partir d'un codage sur plusieurs couches construites à partir d'une même vidéo à différentes échelles de résolutions, fréquences, niveaux de qualité, profondeurs des pixels ou espaces de couleur. Le codage SHVC améliore l'efficacité du codage HEVC grâce à une prédiction inter-couches qui consistent à employer les informations de codage issues des couches les plus basses. La solution proposée dans cette thèse s'appuie sur un codeur HEVC professionnel développé par la société Ateme qui intègre plusieurs niveaux de parallélisme (inter-images, intra-images, inter-blocs et inter-opérations) grâce à une architecture en pipeline. Deux instances parallèles de ce codeur sont synchronisées via un décalage inter-pipelines afin de réaliser une prédiction inter-couches. Des compromis entre complexité et efficacité de codage sont effectués au sein de cette prédiction au niveau des types d'image et des outils de prédiction. Dans un cadre de diffusion, par exemple, la prédiction inter-couches est effectuée sur les textures pour une image sur deux. A qualité constante, ceci permet d'économiser 18.5% du débit pour une perte de seulement 2% de la vitesse par rapport à un codage HEVC. L'architecture employée permet alors de réaliser tous les types de scalabilité supportés par l'extension SHVC. De plus, pour une scalabilité en résolution, nous proposons un filtre de sous-échantillonnage, effectué sur la couche de base, qui optimise le coût en débit global. Nous proposons des modes de qualité intégrant plusieurs niveaux de parallélisme et optimisations à bas niveau qui permettent de réaliser des codages en temps-réel sur des formats UHD. La solution proposée a été intégrée dans une chaîne de diffusion vidéo temps-réel et montrée lors de plusieurs salons, conférences et meetinqs ATSC 3.0. / After entering the digital era, video consumption evolved and defined new trends. Video contents can now be accessed with many platforms (television, computer, tablet, smartphones ... ) and from many medias such as mobile network or satellite network or terrestrial network or Internet or local storage on Blu-ray disc for instance. In the meantime, users experience improves thanks to new video format such as Ultra High Definition (UHD) or High Dynamic Range (HOR) or High Frame Rate (HFR). These formats respectively enhance quality through resolution, dynamic range and frequency. New consumption trends and new video formats define new constraints that have to be resolved by currents and futures video encoders. In this context, we propose a video coding solution able to answer constraints such as multi-formats coding, multi­destinations coding, coding speed and coding efficiency in terms of video compression. This solution relies on the scalable extension of the standard « High Efficiency Video Coding » (HEVC) defined in 2014 also called SHVC. This extension enables scalable video coding by producing a single bitstream on several layers built from a common video at different scales of resolution, frequency, quality, bit depth per pixel or even colour gamut. SHVC coding enhance HEVC coding thanks to an inter-layer prediction that use coding information from lower layers. In this PhD thesis, the proposed solution is based on a professional video encoder, developed by Ateme company, able to perform parallelism on several levels (inter-frames, intra-frames, inter-blocks, inter-operations) thanks to a pipelined architecture. Two instances of this encoder run in parallel and are synchronised at pipeline level to enable inter-layer predictions. Some trade-off between complexity and coding efficiency are proposed on inter-layer prediction at slice and prediction tools levels. For instance, in a broadcast configuration, inter-layer prediction is processed on reconstructed pictures only for half the frames of the bitstream. In a constant quality configuration, it enables to save 18.5% of the coding bitrate for only 2% loss in terms of coding speed compared to equivalent HEVC coding. The proposed architecture is also able to perform all kinds of scalability supported in the SHVC extension. Moreover, in spatial scalability, we propose a down-sampling filter processed on the base layer that optimized global coding bitrate. We propose several quality modes with parallelism on several levels and low-level optimization that enable real-time video coding on UHD sequences. The proposed solution was integrated in a video broadcast chain and showed in several professional shows, conferences and at ATSC 3.0 meetings.

In a wireless and mobile communication paradigm, distribution and sharing of video content often occurs over unfriendly network environments constrained by lack of sufficient bandwidth, and prone to jitter, delay and packet losses. The research presented in this thesis proposed an assortment of application-specific optimizations designed to enable high-quality video communication over bandwidth constrained and unreliable channels. This assortment of solutions, termed herein as the Application Specific Video Coding and Delivery (ASVCD) toolkit, comprises of content and network adaptive approaches such as Region of Interest (ROI) video coding, Multiple Representation Coding (MRC), and Multiple Representation Coding of the Region of Interest (ROI + MRC). Thus, the effectiveness of ROI based video-coding in facilitating diagnostically lossless delivery of surgical videos over very low bandwidth channels was studied in this thesis. Furthermore, to facilitate error resilient video delivery over channels prone to burst losses and signal loss intervals, the MRC scheme was presented in this thesis. Finally, the thesis proposed a scheme for unequal protection of the ROI in the video by using the MRC scheme to effectively enable a distance learning application. To summarize, the ASVCD toolkit contributed in enabling high-quality video communications applications to become seamless and pervasive.

L'objectif de cette thèse est le déploiement et l'évaluation d'une plate-forme de télé-échographie mobile, utilisée pour fournir un diagnostic et des soins à distance dans des milieux médicalement isolés. La plateforme intègre de nouveaux concepts qui permettent de l’utilisation de la télé-échographie robotisée sur les réseaux sans fil 3G, 4G et 5G pour satisfaire au transfert de qualité des vidéos ultrasonores pour un diagnostic médical robuste. Ce travail contribue au domaine des Sciences et Technologies de l'Information et de la Communication appliquées au secteur de la santé et en particulier à la robotique médicale téléopérée. Les principales contributions de la thèse sont : I. Un état de l’art des systèmes télé-robotiques appliqués au médical menée sur la base de publications écrites entre 2004 et 2016, II. L'évaluation objective et subjective (clinique) de la qualité vidéo a démontré que les normes H.264/AVC et HEVC peuvent atteindre une qualité vidéo sans perte de diagnostic à des débits (1024 et 2048 Kbps) bien en deçà des débits de données supportés par les réseaux 4G. Les normes de codage vidéo antérieures (Mpeg-4, Mpeg-2) ne peuvent pas être utilisées pour le diagnostic clinique à ces débits car elles présentent une perte d'information pour le diagnostic médical, III. Les experts médicaux ont apprécié la réactivité dynamique mécanique de la plate-forme en raison du faible délai présenté par les canaux LTE. La limitation la plus importante soulevée par l'expert médical, empêchant une évaluation globale clinique favorable au diagnostic, était le positionnement initial du robot sur le corps du patient et son déplacement vers l'obtention d’une échographie cardiaque, Les résultats fournissent une forte indication que la plate-forme télé-échographie robotisée peut être utilisée pour fournir un diagnostic fiable et à distance sur les réseaux sans fil émergents 4G et au-delà. / The objective of this Thesis was the deployment and evaluation of an end-to-end mobile tele-echography platform used to provide remote diagnosis and care within medically isolated settings. The platform integrates new concepts that enable robotized tele-echography over commercially available 4G and beyond mobile networks for rendering diagnostically robust medical ultrasound video. It contributes to the field of Information and Communication technologies applied in the healthcare sector. The main contributions of the Thesis are: I. A systematic review on the state of the art in medical telerobotic systems was conducted based on publications of the last decade, and more specifically between the years 2004 to 2016. II. Both objective and subjective (clinical) video quality assessment demonstrated that H.264/AVC and HEVC standards can achieve diagnostically-lossless video quality at bitrates (1024 and 2048 Kbps) well within the LTE supported data rates. Earlier video coding standards (Mpeg-4 & Mpeg-2) cannot be employed for clinical diagnosis at these rates as they present loss of clinical information.III. Medical experts highly appreciated the proposed platform’s mechanical dynamic responsiveness due to the low end-to-end delay (latency) facilitated by LTE-channels. The most important limitation raised by the medical expert and prevented higher overall rating and ultimately clinical QoE was the robot initial positioning on the patient’s body and navigation towards obtaining the cardiac ultrasound. IV. Results provides a strong indication that the proposed robotized tele-echography platform can be used to provide reliable, remote diagnosis over emerging 4G and beyond wireless networks.

[pt] As técnicas de estimação de movimento utilizadas nos padrões de compressão de vídeo proporcionam a utilização mais eficiente dos recursos de transmissão e armazenamento, através da redução do número de bits necessários para representar um sinal de vídeo e da conservação da qualidade do conteúdo que está sendo processado. O objetivo dessa dissertação de Mestrado é propor um novo algoritmo capaz de reduzir a grande complexidade computacional envolvida nestas técnicas, mantendo a qualidade do sinal reconstruído. Dessa maneira, apresenta-se um algoritmo AUMHS (Adaptive Unsymmetrical-cross Multi-Hexagon-grid Search) o qual traz como principais modificações ao algoritmo UMHS (Unsymmetrical-cross Multi-Hexagon-grid Search) a implementação de uma medida de movimento que classifica as cenas de uma seqüência de vídeo de acordo com o movimento detectado para posterior adequação dos parâmetros de estimação de movimento e de outros parâmetros do codificador. Como resultado apresenta-se um ganho expressivo na velocidade de processamento, e conseqüente redução do custo computacional, conservando-se a qualidade obtida pelos principais algoritmos da literatura. O algoritmo foi implementado no codificador do padrão H.264/AVC onde realizou-se análises comparativas de desempenho com os algoritmos UMHS e FSA através da medição de parâmetros como PSNR (Peak Signal to Noise Ratio), tempo de processamento do codificador, tempo de processamento do módulo de estimação de movimento, taxa de bits utilizada e avaliação subjetiva informal. / [en] The motion estimation techniques used by the video compression standards provide an efficient utilization of the transmission and storage resources, through the reduction of the number of bits required to represent a video signal and the conservation of the content quality that is being processed. The objective of this work is to propose a new algorithm capable of reducing the great computational complexity involved in the motion estimation techniques, keeping the quality of the reconstructed signal. In this way, we present an algorithm called AUMHS (Adaptive Unsymmetrical-cross Multi-Hexagon-grid Search) which brings as main modifications relative to the UMHS (Unsymmetrical-cross Multi-Hexagon-grid Search) the implementation of a movement measure that can classify the scenes of a video sequence according to the motion detected for posterior adequacy of the motion estimation and others coder parameters. As result we present an expressive gain in the processing speed, and consequent computational cost reduction, conserving the same quality of the main algorithms published in the literature. The algorithm was implemented in the H.264/AVC coder in order to proceed with comparative analysis of perfomance together with the UMHS and FSA algorithms, measuring parameters as PSNR (Peak Signal you the Noise Ratio), coding processing time, motion estimation time, bit rate, and informal subjective evaluation.