A family of stereoscopic image compression algorithms using wavelet transforms

With the standardization of JPEG-2000, wavelet-based image and video compression technologies are gradually replacing the popular DCT-based methods. In parallel to this, recent developments in autostereoscopic display technology is now threatening to revolutionize the way in which consumers are used to enjoying the traditional 2D display based electronic media such as television, computer and movies. However, due to the two-fold bandwidth/storage space requirement of stereoscopic imaging, an essential requirement of a stereo imaging system is efficient data compression. In this thesis, seven wavelet-based stereo image compression algorithms are proposed, to take advantage of the higher data compaction capability and better flexibility of wavelets. In the proposed CODEC I, block-based disparity estimation/compensation (DE/DC) is performed in pixel domain. However, this results in an inefficiency when DWT is applied on the whole predictive error image that results from the DE process. This is because of the existence of artificial block boundaries between error blocks in the predictive error image. To overcome this problem, in the remaining proposed CODECs, DE/DC is performed in the wavelet domain. Due to the multiresolution nature of the wavelet domain, two methods of disparity estimation and compensation have been proposed. The first method is performing DEJDC in each subband of the lowest/coarsest resolution level and then propagating the disparity vectors obtained to the corresponding subbands of higher/finer resolution. Note that DE is not performed in every subband due to the high overhead bits that could be required for the coding of disparity vectors of all subbands. This method is being used in CODEC II. In the second method, DEJDC is performed m the wavelet-block domain. This enables disparity estimation to be performed m all subbands simultaneously without increasing the overhead bits required for the coding disparity vectors. This method is used by CODEC III. However, performing disparity estimation/compensation in all subbands would result in a significant improvement of CODEC III. To further improve the performance of CODEC ill, pioneering wavelet-block search technique is implemented in CODEC IV. The pioneering wavelet-block search technique enables the right/predicted image to be reconstructed at the decoder end without the need of transmitting the disparity vectors. In proposed CODEC V, pioneering block search is performed in all subbands of DWT decomposition which results in an improvement of its performance. Further, the CODEC IV and V are able to perform at very low bit rates(< 0.15 bpp). In CODEC VI and CODEC VII, Overlapped Block Disparity Compensation (OBDC) is used with & without the need of coding disparity vector. Our experiment results showed that no significant coding gains could be obtained for these CODECs over CODEC IV & V. All proposed CODECs m this thesis are wavelet-based stereo image coding algorithms that maximise the flexibility and benefits offered by wavelet transform technology when applied to stereo imaging. In addition the use of a baseline-JPEG coding architecture would enable the easy adaptation of the proposed algorithms within systems originally built for DCT-based coding. This is an important feature that would be useful during an era where DCT-based technology is only slowly being phased out to give way for DWT based compression technology. In addition, this thesis proposed a stereo image coding algorithm that uses JPEG-2000 technology as the basic compression engine. The proposed CODEC, named RASTER is a rate scalable stereo image CODEC that has a unique ability to preserve the image quality at binocular depth boundaries, which is an important requirement in the design of stereo image CODEC. The experimental results have shown that the proposed CODEC is able to achieve PSNR gains of up to 3.7 dB as compared to directly transmitting the right frame using JPEG-2000

Non-expansive symmetrically extended wavelet transform for arbitrarily shaped video object plane.

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

Livrable D3.3 of the PERSEE project : 2D coding tools

49Livrable D3.3 du projet ANR PERSEECe rapport a été réalisé dans le cadre du projet ANR PERSEE (n° ANR-09-BLAN-0170). Exactement il correspond au livrable D3.3 du projet. Son titre : 2D coding tool

Motion compensation and very low bit rate video coding

Recently, many activities of the International Telecommunication Union (ITU) and the International Standard Organization (ISO) are leading to define new standards for very low bit-rate video coding, such as H.263 and MPEG-4 after successful applications of the international standards H.261 and MPEG-1/2 for video coding above 64kbps. However, at very low bit-rate the classic block matching based DCT video coding scheme suffers seriously from blocking artifacts which degrade the quality of reconstructed video frames considerably. To solve this problem, a new technique in which motion compensation is based on dense motion field is presented in this dissertation. Four efficient new video coding algorithms based on this new technique for very low bit-rate are proposed. (1) After studying model-based video coding algorithms, we propose an optical flow based video coding algorithm with thresh-olding techniques. A statistic model is established for distribution of intensity difference between two successive frames, and four thresholds are used to control the bit-rate and the quality of reconstructed frames. It outperforms the typical model-based techniques in terms of complexity and quality of reconstructed frames. (2) An efficient algorithm using DCT coded optical flow. It is found that dense motion fields can be modeled as the first order auto-regressive model, and efficiently compressed with DCT technique, hence achieving very low bit-rate and higher visual quality than the H.263/TMN5. (3) A region-based discrete wavelet transform video coding algorithm. This algorithm implements dense motion field and regions are segmented according to their content significance. The DWT is applied to residual images region by region, and bits are adaptively allocated to regions. It improves the visual quality and PSNR of significant regions while maintaining low bit-rate. (4) A segmentation-based video coding algorithm for stereo sequence. A correlation-feedback algorithm with Kalman filter is utilized to improve the accuracy of optical flow fields. Three criteria, which are associated with 3-D information, 2-D connectivity and motion vector fields, respectively, are defined for object segmentation. A chain code is utilized to code the shapes of the segmented objects. it can achieve very high compression ratio up to several thousands