Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 57-61)

With the evolution of multimedia systems, image and video compression is becoming the key enabling technology for delivering various image/video services over heterogeneous networks. The basic goal of image data compression is to reduce the bit rate for transmission and storage while either maintaining the original quality of the data or providing an acceptable quality. This thesis proposes a new wavelet transform for lossless compression of images with application to medical images. The transform uses integer arithmetic and is very computationally efficient. Then a new color image transformation, which is reversible and uses integer arithmetic, is proposed. The transformation reduces the redundancy among the red, green, and blue color bands. It approximates the luminance and chrominance components of the YIQ coordinate system. This transformation involves no floating point/integer multiplications or divisions, and is, therefore, very suitable for real-time applications where the number of CPU cycles needs to be kept to a minimum. A technique for lossy compression of an image data base is also proposed. The technique uses a wavelet transform and vector quantization for compression. The discrete cosine transform is applied to the coarsest scale wavelet coefficients to achieve even higher compression ratios without any significant increase in computational complexity. Wavelet denoising is used to reduce the image artifacts generated by quantizing the discrete cosine transform coefficients. This improves the subjective quality of the decompressed images for very low bit rate images (less than 0.5 bits per pixel). The thesis also deals with the real-time implementation of the wavelet transform. The new wavelet transform has been applied to speech signals. Both lossless and lossy techniques for speech coding have been implemented. The lossless technique involves using the reversible integer-arithmetic wavelet transform and Huffman coding to obtain the compressed bitstream. The lossy technique, on the other hand, quantizes the wavelet coefficients to obtain higher compression ratio at the expense of some degradation in sound quality. The issues related to real-time wavelet compression are also discussed. Due to the limited size of memory on a DSP, a wavelet transform had to be applied to an input signal of finite length. The effects of varying the signal length on compression performance are also studied for different reversible wavelet transforms. The limitations of the proposed techniques are discussed and recommendations for future research are provided. / Graduate

In this thesis, most commonly encountered video compression techniques and international coding standards are studied. The study leads to the idea of a reconfigurable codec which can adapt itself to the specific requirements of diverse applications so as to achieve improved performance. Firstly, we propose a multiple layer affine motion compensated codec which acts as a basic building block of the reconfigurable multiple tool video codec. A detailed investigation of the properties of the proposed codec is carried out. The experimental results reveal that the gain in coding efficiency from improved motion prediction and segmentation is proportional to the spatial complexity of the sequence being encoded. Secondly, a framework for the reconfigurable multiple tool video codec is developed and its key parts are discussed in detail. Two important concepts virtual codec and virtual tool are introduced. A prototype of the proposed reconfigurable multiple tool video codec is implemented. The codec structure and the constituent tools of the codec included in the prototype are extensively tested and evaluated to prove the concept. The results confirm that different applications require different codec configurations to achieve optimum performance. Thirdly, a knowledge based tool selection system for the reconfigurable codec is proposed and developed. Human knowledge as well as sequence properties are taken into account in the tool selection procedure. It is shown that the proposed tool selection mechanism gives promising results. Finally, concluding remarks are offered and future research directions are suggested.

Les codeurs vidéo état de l’art utilisent des transformées pour assurer une représentation compacte du signal. L’étape de transformation constitue le domaine dans lequel s’effectue la compression, pourtant peu de variabilité dans les types de transformations est constatée dans les systèmes de codage vidéo normalisés : souvent, une seule transformée est considérée, habituellement la transformée en cosinus discrète (DCT). Récemment, d’autres transformées ont commencé à être considérées en complément de la DCT. Par exemple, dans le dernier standard de compression vidéo, nommé HEVC (High Efficiency Video Coding), les blocs de taille 4x4 peuvent utiliser la transformée en sinus discrète (DST), de plus, il est également possible de ne pas les transformer. Ceci révèle un intérêt croissant pour considérer une pluralité de transformées afin d’augmenter les taux de compression. Cette thèse se concentre sur l’extension de HEVC au travers de l’utilisation de multiples transformées. Après une introduction générale au codage vidéo et au codage par transformée, une étude détaillée de deux méthodes de construction de transformations est menée : la transformée de Karhunen Loève (KLT) et une transformée optimisée en débit et distorsion sont considérées. Ces deux méthodes sont comparées entre-elles en substituant les transformées utilisées par HEVC. Une expérimentation valide la pertinence des approches. Un schéma de codage qui incorpore et augmente l’utilisation de multiples transformées est alors introduit : plusieurs transformées sont mises à disposition de l’encodeur, qui sélectionne celle qui apporte le meilleur compromis dans le plan débit distorsion. Pour ce faire, une méthode de construction qui permet de concevoir des systèmes comportant de multiples transformations est décrite. Avec ce schéma de codage, le débit est significativement réduit par rapport à HEVC, tout particulièrement lorsque les transformées sont nombreuses et complexes à mettre en oeuvre. Néanmoins, ces améliorations viennent au prix d’une complexité accrue en termes d’encodage, de décodage et de contrainte de stockage. En conséquence, des simplifications sont considérées dans la suite du document, qui ont vocation à limiter l’impact en réduction de débit. Une première approche est introduite dans laquelle des transformées incomplètes sont motivées. Les transformations de ce type utilisent un seul vecteur de base, et sont conçues pour travailler de concert avec les transformations de HEVC. Cette technique est évaluée et apporte une réduction de complexité significative par rapport au précédent système, bien que la réduction de débit soit modeste. Une méthode systématique, qui détermine les meilleurs compromis entre le nombre de transformées et l’économie de débit est alors définie. Cette méthode utilise deux types différents de transformée : basés sur des transformées orthogonales séparables et des transformées trigonométriques discrètes (DTT) en particulier. Plusieurs points d’opération sont présentés qui illustrent plusieurs compromis complexité / gain en débit. Ces systèmes révèlent l’intérêt de l’utilisation de transformations multiples pour le codage vidéo. / State of the art video codecs use transforms to ensure a compact signal representation. The transform stage is where compression takes place, however, little variety is observed in the type of transforms used for standardised video coding schemes: often, a single transform is considered, usually a Discrete Cosine Transform (DCT). Recently, other transforms have started being considered in addition to the DCT. For instance, in the latest video coding standard, High Efficiency Video Coding (HEVC), the 4x4 sized blocks can make use of the Discrete Sine Transform (DST) and, in addition, it also possible not to transform them. This fact reveals an increasing interest to consider a plurality of transforms to achieve higher compression rates. This thesis focuses on extending HEVC through the use of multiple transforms. After a general introduction to video compression and transform coding, two transform designs are studied in detail: the Karhunen Loève Transform (KLT) and a Rate-Distortion Optimised Transform are considered. These two methods are compared against each other by replacing the transforms in HEVC. This experiment validates the appropriateness of the design. A coding scheme that incorporates and boosts the use of multiple transforms is introduced: several transforms are made available to the encoder, which chooses the one that provides the best rate-distortion trade-off. Consequently, a design method for building systems using multiple transforms is also described. With this coding scheme, significant amounts of bit-rate savings are achieved over HEVC, especially when using many complex transforms. However, these improvements come at the expense of increased complexity in terms of coding, decoding and storage requirements. As a result, simplifications are considered while limiting the impact on bit-rate savings. A first approach is introduced, in which incomplete transforms are used. This kind of transforms use one single base vector and are conceived to work as companions of the HEVC transforms. This technique is evaluated and provides significant complexity reductions over the previous system, although the bit-rate savings are modest. A systematic method, which specifically determines the best trade-offs between the number of transforms and bit-rate savings, is designed. This method uses two different types of transforms based separable orthogonal transforms and Discrete Trigonometric Transforms (DTTs) in particular. Several designs are presented, allowing for different complexity and bitrate savings trade-offs. These systems reveal the interest of using multiple transforms for video coding.

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The older F16 jet fighters are currently being flight tested to evaluate the upgraded electronics for aircraft avionics, flight control and weapons systems. An instrumentation system capable of recording three different video signals, recording four Military- Standard-1553B (Mil-Std-1553B) data streams, recording one PCM stream, transmitting the PCM stream, and transmitting two video signals was needed. Using off the shelf equipment, the F16 instrumentation system was design to meet the electronic specifications, limited available space of a small jet fighter, and limited space in the SBand frequency range.

The recent advances in sensor and display technologies have brought upon the High Dynamic Range (HDR) imaging capability. The modern multiple exposure HDR sensors can achieve the dynamic range of 100-120 dB and LED and OLED display devices have contrast ratios of 10^5:1 to 10^6:1. Despite the above advances in technology the image/video compression algorithms and associated hardware are yet based on Standard Dynamic Range (SDR) technology, i.e. they operate within an effective dynamic range of up to 70 dB for 8 bit gamma corrected images. Further the existing infrastructure for content distribution is also designed for SDR, which creates interoperability problems with true HDR capture and display equipment. The current solutions for the above problem include tone mapping the HDR content to fit SDR. However this approach leads to image quality associated problems, when strong dynamic range compression is applied. Even though some HDR-only solutions have been proposed in literature, they are not interoperable with current SDR infrastructure and are thus typically used in closed systems. Given the above observations a research gap was identified in the need for efficient algorithms for the compression of still images and video, which are capable of storing full dynamic range and colour gamut of HDR images and at the same time backward compatible with existing SDR infrastructure. To improve the usability of SDR content it is vital that any such algorithms should accommodate different tone mapping operators, including those that are spatially non-uniform. In the course of the research presented in this thesis a novel two layer CODEC architecture is introduced for both HDR image and video coding. Further a universal and computationally efficient approximation of the tone mapping operator is developed and presented. It is shown that the use of perceptually uniform colourspaces for internal representation of pixel data enables improved compression efficiency of the algorithms. Further proposed novel approaches to the compression of metadata for the tone mapping operator is shown to improve compression performance for low bitrate video content. Multiple compression algorithms are designed, implemented and compared and quality-complexity trade-offs are identified. Finally practical aspects of implementing the developed algorithms are explored by automating the design space exploration flow and integrating the high level systems design framework with domain specific tools for synthesis and simulation of multiprocessor systems. The directions for further work are also presented.

by Roland Siu-kwong Ip. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 101-[105]). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Image Compression --- p.2 / Chapter 1.2.1 --- Classification of Image Compression --- p.2 / Chapter 1.2.2 --- Lossy Compression Approaches --- p.3 / Chapter 1.3 --- Video Compression --- p.4 / Chapter 1.3.1 --- Video Compression System --- p.5 / Chapter 1.4 --- Stereoscopic Video Compression --- p.6 / Chapter 1.5 --- Organization of the thesis --- p.6 / Chapter 2 --- Motion Video Coding Theory --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Representations --- p.8 / Chapter 2.2.1 --- Temporal Processing --- p.13 / Chapter 2.2.2 --- Spatial Processing --- p.19 / Chapter 2.3 --- Quantization --- p.25 / Chapter 2.3.1 --- Scalar Quantization --- p.25 / Chapter 2.3.2 --- Vector Quantization --- p.27 / Chapter 2.4 --- Code Word Assignment --- p.29 / Chapter 2.5 --- Selection of Video Coding Standard --- p.31 / Chapter 3 --- MPEG Compatible Stereoscopic Coding --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- MPEG Compatibility --- p.36 / Chapter 3.3 --- Stereoscopic Video Coding --- p.37 / Chapter 3.3.1 --- Coding by Stereoscopic Differences --- p.37 / Chapter 3.3.2 --- I-pictures only Disparity Coding --- p.40 / Chapter 3.4 --- Stereoscopic MPEG Encoder --- p.44 / Chapter 3.4.1 --- Stereo Disparity Estimator --- p.45 / Chapter 3.4.2 --- Improved Disparity Estimation --- p.47 / Chapter 3.4.3 --- Stereo Bitstream Multiplexer --- p.49 / Chapter 3.5 --- Generic Implementation --- p.50 / Chapter 3.5.1 --- Macroblock Converter --- p.54 / Chapter 3.5.2 --- DCT Functional Block --- p.55 / Chapter 3.5.3 --- Rate Control --- p.57 / Chapter 3.6 --- Stereoscopic MPEG Decoder --- p.58 / Chapter 3.6.1 --- Mono Playback --- p.58 / Chapter 3.6.2 --- Stereo Playback --- p.60 / Chapter 4 --- Performance Evaluation --- p.63 / Chapter 4.1 --- Introduction --- p.63 / Chapter 4.2 --- Test Sequences Generation --- p.63 / Chapter 4.3 --- Simulation Environment --- p.64 / Chapter 4.4 --- Simulation Results --- p.65 / Chapter 4.4.1 --- Objective Results --- p.65 / Chapter 4.4.2 --- Subjective Results --- p.72 / Chapter 5 --- Conclusions --- p.80 / Chapter A --- MPEG ´ؤ An International Standard --- p.83 / Chapter A.l --- Introduction --- p.83 / Chapter A.2 --- Preprocessing --- p.84 / Chapter A.3 --- Data Structure of Pictures --- p.85 / Chapter A.4 --- Picture Coding --- p.86 / Chapter A.4.1 --- Coding of Motion Vectors --- p.90 / Chapter A.4.2 --- Coding of Quantized Coefficients --- p.94 / References --- p.101

by Lai Hin Lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 54-57). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iv / Table of Contents --- p.v / List of Figures --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Related Works --- p.8 / Chapter 2.1 --- Source Modeling --- p.9 / Chapter 2.2 --- CBR Scheduler for VBR Delivery --- p.11 / Chapter 2.3 --- Brute Force Scheduler: --- p.15 / Chapter 2.4 --- Temporal Smoothing Scheduler: --- p.16 / Chapter Chapter 3 --- Decreasing Rate Scheduling --- p.22 / Chapter 3.1 --- MDRS with Minimum Buffer Requirement --- p.25 / Chapter 3.2 --- 2-Rate MDRS --- p.31 / Chapter Chapter 4 --- Performance Evaluation --- p.33 / Chapter 4.1 --- Buffer Requirement --- p.35 / Chapter 4.2 --- Startup Delay --- p.38 / Chapter 4.3 --- Disk Utilization --- p.39 / Chapter 4.4 --- Complexity --- p.43 / Chapter Chapter 5 --- Conclusion --- p.49 / Appendix --- p.51 / Bibliography --- p.54

Cheung Man-kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 116-120). / Abstracts in English and Chinese. / Chapter 1) --- Introduction --- p.1 / Chapter 1.1) --- Building of the 3D Wireframe and Facial Model --- p.2 / Chapter 1.2) --- Description of 3D Model Based Video Conferencing --- p.3 / Chapter 1.3) --- Wireframe Model Fitting or Conformation --- p.6 / Chapter 1.4) --- Pose Estimation --- p.8 / Chapter 1.5) --- Facial Motion Estimation and Synthesis --- p.9 / Chapter 1.6) --- Thesis Outline --- p.10 / Chapter 2) --- Wireframe model Fitting --- p.11 / Chapter 2.1) --- Algorithm of WFM Fitting --- p.12 / Chapter 2.1.1) --- Global Deformation --- p.14 / Chapter a) --- Scaling --- p.14 / Chapter b) --- Shifting --- p.15 / Chapter 2.1.2) --- Local Deformation --- p.15 / Chapter a) --- Shifting --- p.16 / Chapter b) --- Scaling --- p.17 / Chapter 2.1.3) --- Fine Updating --- p.17 / Chapter 2.2) --- Steps of Fitting --- p.18 / Chapter 2.3) --- Functions of Different Deformation --- p.18 / Chapter 2.4) --- Experimental Results --- p.19 / Chapter 2.4.1) --- Output wireframe in each step --- p.19 / Chapter 2.4.2) --- Examples of Mis-fitted wireframe with incoming image --- p.22 / Chapter 2.4.3) --- Fitted 3D facial wireframe --- p.23 / Chapter 2.4.4) --- Effect of mis-fitted wireframe after compensation of motion --- p.24 / Chapter 2.5) --- Summary --- p.26 / Chapter 3) --- Epipolar Geometry --- p.27 / Chapter 3.1) --- Pinhole Camera Model and Perspective Projection --- p.28 / Chapter 3.2) --- Concepts in Epipolar Geometry --- p.31 / Chapter 3.2.1) --- Working with normalized image coordinates --- p.33 / Chapter 3.2.2) --- Working with pixel image coordinates --- p.35 / Chapter 3.2.3) --- Summary --- p.37 / Chapter 3.3) --- 8-point Algorithm (Essential and Fundamental Matrix) --- p.38 / Chapter 3.3.1) --- Outline of the 8-point algorithm --- p.38 / Chapter 3.3.2) --- Modification on obtained Fundamental Matrix --- p.39 / Chapter 3.3.3) --- Transformation of Image Coordinates --- p.40 / Chapter a) --- Translation to mean of points --- p.40 / Chapter b) --- Normalizing transformation --- p.41 / Chapter 3.3.4) --- Summary of 8-point algorithm --- p.41 / Chapter 3.4) --- Estimation of Object Position by Decomposition of Essential Matrix --- p.43 / Chapter 3.4.1) --- Algorithm Derivation --- p.43 / Chapter 3.4.2) --- Algorithm Outline --- p.46 / Chapter 3.5) --- Noise Sensitivity --- p.48 / Chapter 3.5.1) --- Rotation vector of model --- p.48 / Chapter 3.5.2) --- The projection of rotated model --- p.49 / Chapter 3.5.3) --- Noisy image --- p.51 / Chapter 3.5.4) --- Summary --- p.51 / Chapter 4) --- Pose Estimation --- p.54 / Chapter 4.1) --- Linear Method --- p.55 / Chapter 4.1.1) --- Theory --- p.55 / Chapter 4.1.2) --- Normalization --- p.57 / Chapter 4.1.3) --- Experimental Results --- p.58 / Chapter a) --- Synthesized image by linear method without normalization --- p.58 / Chapter b) --- Performance between linear method with and without normalization --- p.60 / Chapter c) --- Performance of linear method under quantization noise with different transformation components --- p.62 / Chapter d) --- Performance of normalized case without transformation in z- component --- p.63 / Chapter 4.1.4) --- Summary --- p.64 / Chapter 4.2) --- Two Stage Algorithm --- p.66 / Chapter 4.2.1) --- Introduction --- p.66 / Chapter 4.2.2) --- The Two Stage Algorithm --- p.67 / Chapter a) --- Stage 1 (Iterative Method) --- p.68 / Chapter b) --- Stage 2 ( Non-linear Optimization) --- p.71 / Chapter 4.2.3) --- Summary of the Two Stage Algorithm --- p.72 / Chapter 4.2.4) --- Experimental Results --- p.72 / Chapter 4.2.5) --- Summary --- p.80 / Chapter 5) --- Facial Motion Estimation and Synthesis --- p.81 / Chapter 5.1) --- Facial Expression based on face muscles --- p.83 / Chapter 5.1.1) --- Review of Action Unit Approach --- p.83 / Chapter 5.1.2) --- Distribution of Motion Unit --- p.85 / Chapter 5.1.3) --- Algorithm --- p.89 / Chapter a) --- For Unidirectional Motion Unit --- p.89 / Chapter b) --- For Circular Motion Unit (eyes) --- p.90 / Chapter c) --- For Another Circular Motion Unit (mouth) --- p.90 / Chapter 5.1.4) --- Experimental Results --- p.91 / Chapter 5.1.5) --- Summary --- p.95 / Chapter 5.2) --- Detection of Facial Expression by Muscle-based Approach --- p.96 / Chapter 5.2.1) --- Theory --- p.96 / Chapter 5.2.2) --- Algorithm --- p.97 / Chapter a) --- For Sheet Muscle --- p.97 / Chapter b) --- For Circular Muscle --- p.98 / Chapter c) --- For Mouth Muscle --- p.99 / Chapter 5.2.3) --- Steps of Algorithm --- p.100 / Chapter 5.2.4) --- Experimental Results --- p.101 / Chapter 5.2.5) --- Summary --- p.103 / Chapter 6) --- Conclusion --- p.104 / Chapter 6.1) --- WFM fitting --- p.104 / Chapter 6.2) --- Pose Estimation --- p.105 / Chapter 6.3) --- Facial Estimation and Synthesis --- p.106 / Chapter 6.4) --- Discussion on Future Improvements --- p.107 / Chapter 6.4.1) --- WFM Fitting --- p.107 / Chapter 6.4.2) --- Pose Estimation --- p.109 / Chapter 6.4.3) --- Facial Motion Estimation and Synthesis --- p.110 / Chapter 7) --- Appendix --- p.111 / Chapter 7.1) --- Newton's Method or Newton-Raphson Method --- p.111 / Chapter 7.2) --- H.261 --- p.113 / Chapter 7.3) --- 3D Measurement --- p.114 / Bibliography --- p.116

Based on the fixed block size FWS algorithm, we further proposed a fast full-pel variable block size motion estimation algorithm called Fast Walsh Search in Variable Block Size (FWS-VBS). As in FWS, FWS-VBS employs the PSAD as the error measure to identify likely mismatches. Mismatches are rejected by thresholding method and the thresholds are determined adaptively to cater for different activity levels in each block. Early termination techniques are employed to further reduce the number of candidates and modes to be searched of each block. FWS-VBS performs equally well to the exhaustive full search algorithm in the reference H.264/AVC encoder and requires only about 10% of the computation time. / Furthermore, we modified our proposed segmentation algorithm to handle video sequences that are already encoded in the H.264 format. Since the video is compressed, no spatial information is available. Instead, quantized transform coefficients of the residual frame are used to approximate spatial information and improve segmentation result. The computation time of the segmentation process is merely about 16ms per frame for CIF frame size video, allowing the algorithm to be applied in real-time applications such as video surveillance and conferencing. / In the first part of our research, we proposed a block matching algorithm called Fast Walsh Search (FWS) for video motion estimation. FWS employs two new error measures defined in Walsh Hadamard domain, which are partial sum-of-absolute difference (PSAD) and sum-of-absolute difference of DC coefficients (SADDCC). The algorithm first rejects most mismatched candidates using PSAD which is a coarse measure requiring little computation. Because of the energy packing ability of Walsh Hadamard transform (WHT) and the utilization of fast WHT computation algorithm, mismatched candidates are identified and rejected efficiently. Then the proposed algorithm identifies the matched candidate from the remaining candidates using SADDCC which is a more accurate measure and can reuse computation performed for PSAD. Experimental results show that FWS can give good visual quality to most of video scene with a reasonable amount of computation. / In the second part of our research, we developed a real-time video object segmentation algorithm. The motion information is obtained by FWS-VBS to minimize the computation time while maintaining an adequate accuracy. The algorithm makes use of the motion information to identify background motion model and moving objects. In order to preserve spatial and temporal continuity of objects, Markov random field (MRF) is used to model the foreground field. The block-based foreground object mask is obtained by minimizing the energy function of the MRF. The resulting object mask is then post-processed to generate a smooth object mask. Experimental results show that the proposed algorithm can effectively extract moving objects from different kind of sequences, at a speed of less than 100ms per frame for CIF frame size video. / Motion estimation is an important part in many video processing applications, such as video compression, object segmentation, and scene analysis. In all video compression applications, motion information is used to reduce temporal redundancy between frames, thus significantly reduce the required bitrate for transmission and storage of compressed video. In addition, in object-based video coding, video object can be automatically identified by its motion against the background. / Mak, Chun Man. / "June 2008." / Adviser: Wai-Kuen Cham. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1849. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.