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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Progressive refinement of colormapped image.

January 2001 (has links)
Kwong Lap-ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 101-[104]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction to Image Communication --- p.1 / Chapter 1.1 --- Existing Approach improving Image Communication --- p.8 / Chapter 1.1.1 --- Data Compression --- p.8 / Chapter 1.1.2 --- Progressive Image Transmission --- p.10 / Chapter 2 --- Review of Progressive Image Transmission Methods --- p.13 / Chapter 2.1 --- Pyramidal Image Coding --- p.14 / Chapter 2.1.1 --- Expansive Image Pyramid --- p.15 / Chapter 2.1.2 --- Non-Expansive Image Pyramid --- p.18 / Chapter 2.1.3 --- Pros and Cons of Pyramidal Data Structure --- p.19 / Chapter 2.2 --- Hierarchical Data Structure with Bit Plane Transmission --- p.20 / Chapter 2.2.1 --- Bitwise Condensed Quadtree method (BCQ)[6] --- p.21 / Chapter 2.2.2 --- Progressive Transmission of Full-Search VQ[7] --- p.25 / Chapter 2.2.3 --- Pros and Cons of Hierarchical Data Structure with Bit Plane Transmission --- p.26 / Chapter 2.3 --- Embedded Transform Coding --- p.27 / Chapter 2.3.1 --- SPIHT method [16] --- p.27 / Chapter 2.3.2 --- Embedded DCT Method [13] --- p.30 / Chapter 2.3.3 --- Pros and Cons of Embedded Transform Coding --- p.31 / Chapter 2.4 --- Summary --- p.32 / Chapter 3 --- Progressive Refinement of Colormapped Image --- p.34 / Chapter 3.1 --- Colormapped Image --- p.36 / Chapter 3.1.1 --- Pros and Cons of the Usage of Colormapped Image --- p.37 / Chapter 3.2 --- Progressive Refinement in both Spatial and Contrast Resolutions --- p.38 / Chapter 4 --- The Design of Progressive Refinement of Colormapped Image --- p.42 / Chapter 4.1 --- The Scalar Quantization in the YCrCb color space --- p.44 / Chapter 4.1.1 --- The Color Space for Color Quantization --- p.44 / Chapter 4.1.2 --- Color Quantization --- p.44 / Chapter 4.1.3 --- The Order of Quantization --- p.47 / Chapter 4.1.4 --- Pixel Mapping --- p.55 / Chapter 4.2 --- Reordering Pixels --- p.58 / Chapter 4.3 --- Transmission Sequence --- p.61 / Chapter 4.4 --- Changing the progression rate of the spatial and the contrast resolution --- p.62 / Chapter 4.5 --- Data Transmission --- p.69 / Chapter 4.6 --- Displaying the image --- p.70 / Chapter 5 --- Results Analysis & Performance Evaluation --- p.72 / Chapter 5.1 --- Traffic overhead --- p.72 / Chapter 5.2 --- Performance Evaluation --- p.73 / Chapter 5.2.1 --- Experiment --- p.73 / Chapter 5.2.2 --- Comparison with other Methods --- p.81 / Chapter 5.2.3 --- Image quality variation --- p.93 / Chapter 6 --- Discussion and Conclusion --- p.97 / Chapter 6.1 --- Discussion --- p.97 / Chapter 6.2 --- Conclusion --- p.99 / Bibliography --- p.101
22

Lossless video multiplexing for transport over communication networks.

January 1997 (has links)
by Chan Hang Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 62-68). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of video transmission --- p.1 / Chapter 1.2 --- Previous work on lossless video transmission --- p.4 / Chapter 1.3 --- Central theme of thesis ´ؤ Lossless video Aggregation --- p.5 / Chapter 1.4 --- Organization of thesis --- p.9 / Chapter 2 --- Framework of LVAS --- p.11 / Chapter 2.1 --- Review: Transporting single VBR stream using a CBR channel --- p.11 / Chapter 2.2 --- Lossless aggregation of VBR streams --- p.14 / Chapter 3 --- Minimization of Buffer Size --- p.17 / Chapter 3.1 --- A theoretical approach ´ؤ Dynamic programming --- p.19 / Chapter 3.2 --- A practical heuristic ´ؤ Backward Equalization --- p.21 / Chapter 3.3 --- Simulation results of the heuristic method --- p.24 / Chapter 4 --- Bit-rate allocation with fixed buffer --- p.28 / Chapter 4.1 --- Problem formulation --- p.28 / Chapter 4.2 --- Different bit-rate scheduling methods --- p.33 / Chapter 4.3 --- Speed up using point sampling technique --- p.39 / Chapter 4.4 --- Simulation results --- p.44 / Chapter 5 --- Call Admission and Interactive Control for Video Aggregation --- p.50 / Chapter 5.1 --- Call admission issues --- p.50 / Chapter 5.2 --- Interactive Control --- p.53 / Chapter 5.3 --- CBR and ABR hybrid --- p.54 / Chapter 5.4 --- Simulation results --- p.55 / Chapter 6 --- Conclusions and Future research --- p.57 / Chapter 6.1 --- Future Research Suggestions --- p.58 / Chapter 6.2 --- Publications --- p.60 / Bibliography --- p.62
23

An RBF Neural Network Method for Image Progressive Transmission

Chen, Ying-Chung 13 July 2000 (has links)
None
24

Contour encoded compression and transmission /

Nelson, Christopher, January 2006 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Computer Science, 2006. / Includes bibliographical references (p. 141-145).
25

Multiplexing video traffic using frame-skipping aggregation technique.

January 1998 (has links)
by Alan Yeung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 53-[56]). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- MPEG Overview --- p.5 / Chapter 3 --- Framework of Frame-Skipping Lossy Aggregation --- p.10 / Chapter 3.1 --- Video Frames Delivery using Round-Robin Scheduling --- p.10 / Chapter 3.2 --- Underflow Safety Margin on Receiver Buffers --- p.12 / Chapter 3.3 --- Algorithm in Frame-Skipping Aggregation Controller --- p.13 / Chapter 4 --- Replacement of Skipped Frames in MPEG Sequence --- p.17 / Chapter 5 --- Subjective Assessment Test on Frame-Skipped Video --- p.21 / Chapter 5.1 --- Test Settings and Material --- p.22 / Chapter 5.2 --- Choice of Test Methods --- p.23 / Chapter 5.3 --- Test Procedures --- p.25 / Chapter 5.4 --- Test Results --- p.26 / Chapter 6 --- Performance Study --- p.29 / Chapter 6.1 --- Experiment 1: Number of Supportable Streams --- p.31 / Chapter 6.2 --- Experiment 2: Frame-Skipping Rate When Multiplexing on a Leased T3 Link --- p.33 / Chapter 6.3 --- Experiment 3: Bandwidth Usage --- p.35 / Chapter 6.4 --- Experiment 4: Optimal USMT --- p.38 / Chapter 7 --- Implementation Considerations --- p.41 / Chapter 8 --- Conclusions --- p.45 / Chapter A --- The Construction of Stuffed Artificial B Frame --- p.48 / Bibliography --- p.53
26

Noise reduction of image and video signals. / CUHK electronic theses & dissertations collection

January 2012 (has links)
論文研究了圖像及技頻信號的去躁技術,共分為四部分。第一部分研究了用來改進編碼的圖像的主觀同客觀賞質量的方法,介紹了兩個有效的圖像后處理技術。第二部分研究了基於貝葉斯估計鋒的對高斯噪聲圖像的去噪方法。第三部分介紹了對編碼的視頻信號去噪的兩個方法,這些方法可作為視頻環路和后處理濾波器,從而改進視頻信號的編碼性能。第四部分介紹了圖像邊緣檢測技術,該技術可結合基於於邊緣的圖像處理設術來改進含噪圖像的主觀同客觀質量。 / 第一部分,我們研究了一些用來改進編碼的圖像和視頻主觀同客觀質量的有效技術。採用基於塊的離散餘弦變換(DCT) 壓縮標準的圖像和視頻存在編碼效應。為了減少圖像的編碼效應,我們提出了一個基於綫性最小均值平方誤差(MMSE)標準的非局部Kuan (NLK) 濾波器。它被用來恢復量化后的DCT係數,然後我們提出了雙重量非局部Kuan (DNLK) 濾波器。這個DNLK濾波器用在過完備的DCTl係數,進一步形成了過完備雙重非局部Kuan (OCNLK) 濾波器。通過對一些使用測試用的量化表編碼的圖像, JPEG編碼的圖像的實驗,驗證了這兩种方法的有效性。 / 第二部分,我們採用了貝葉斯估計器來估計原始的變換域係數。該方法是對非局部Kuan (NLK) 濾波器的改進,它採用了高斯尺度混合模型來考慮變換域係數的非高斯特性。除去非局部估計的均值后的殘差係數並不是高斯分佈,所以我們採用了高斯混合模型來表示表示這些殘差係數。實驗給果證明了它在圖像去噪應用上的有效性,以及比NLK 濾波器更好的性能。 / 第三部分描述了用來改進視頻編碼性能的基於NLK 的方法。對於採用楨内/間預測和變換編碼的視頻而言,直接使用NLK濾波器將不能有效的去除編碼效應。我們分析了其中的原因,並提出了兩個視頻環路濾波器:基於四叉樹的NLK (QNLK) 濾波器和基於四叉樹的過完備NLK (QOCNLK) 濾波器。NLK 和過完備NLK濾波器用來恢復視頻殘差的量化係數。這些恢復后的係數進一步投射到所設計的量化約數集(QCS)裏。四叉樹技術用來進行自適應的濾波控制。實驗結果表明了相對于H.264/AVC HighProfile ,這些技術達到了可觀的比特率壓縮效率和視覺質量改善。我們同時也採用了QNLK和QOCNLK濾波器進行視頻后處理,並給出了實驗結果和分析。 / 第四部分,我們研究了一個基於非下採樣小波,使用三維隱馬爾可伕模型(HMM)的邊緣檢測技術。 提出的模型不僅能捕獲不同尺度間小波係數的關係,而且考慮了尺度内係數的依賴性。一個計算有效的最大似然(ML) 估計算法用來計算該模型的參數,每一個係數對應的隱含狀態用最大后騐(MAP) 估計來求得。基於一些自然圖像的實驗給果用來評償該算法。對於含噪圖像,該算法可以同時提取邊緣和去除噪聲信號。另外,提出的該模型對於其它的圖像視頻處理任務也是一個潛在的多尺度統計模型工具。 / The thesis investigates techniques to reduce noise in image and video signals.The investigation can be divided into four parts. The first part studies methods to improve the objective and subjective quality of coded images. The proposed two efficient image postprocessing techniques are presented. The second part investigates noise reduction of image signals corrupted by Gaussian noise and presents a denoising method based on Bayes estimator. The third part investigates noise reduction of coded videos by two different approaches. The approaches are used as video loop and postprocessing filters, in order to improve the coding performance of video signals. Finally, the fourth part investigates a new edge detection method that can provide an accurate detection of edges. The method can be used together with edge-based image processing techniques to improve objective and subjective quality of noisy images. / In the first part, the technique to improve the subjective and objective quality of coded images are studied. Coding artifacts exist in images using block-based discrete cosine transform (DCT) compression standards. In order to reduce image coding artifacts, a non-local Kuan's (NLK) filter is proposed from the minimum mean-square-error (MMSE) criterion. It is used to restore quantized DCT coefficients. Then we propose the dual non-local Kuan's (DNLK) filter by applying the NLK filter in dual-layer. The DNLK filter is further extended to form the overcomplete dual non-local Kuan's (OCDNLK) filter by applying to the overcomplete DCT coefficients. Experimental results on coded images using test quantization tables and JPEG coded images show the effectiveness of the two methods. / In the second part, we use a Bayes least square estimator to estimate the original transform coefficients optimally, from the Bayes perspective. It is an improved nonlocal Kuan's filter by considering non-Gaussian property of transform coefficients using Gaussian scale mixture model. The residual coefficients after subtracting non-local estimated means are not Gaussian distributed, so a Gaussian scale mixture model is employed to represent the residual coefficients. Experiments demonstrate its efficiency on image denoising and better performance than the NLK filter. / In the third part, the proposed methods based on the NLK filter to improve video coding performance are studied. Direct application of the NLK filter on videos coded using intra/inter-frame prediction and transform coding cannot improve coding performance efficiently. We identify the causes of the problem and propose quadtree-based NLK (QNLK) loop filter and quadtree-based overcomplete NLK (QOCNLK) loop filter to solve the problem. NLK and overcomplete NLK loop filters are used to restore quantized residual transform coefficients. Restored coefficients are then projected onto designed quantization constraint sets (QCS). Quadtree-based signaling strategy is used for adaptive filtering control. Experimental results show that the proposed loop filtering techniques achieve significant bit rate saving and visual quality improvement compared with H.264 or advanced video coding (AVC) High Profile. We also provide the experimental results and analysis of postprocessing application using QNLK and QOCNLK filters. / In the fourth part, a new edge detecting technique using 3-D Hidden Markov Model (HMM) based on the non-decimated wavelet is studied. The proposed model can not only capture the relationship of wavelet coefficients inter-scale, but also consider the intra-scale dependence. A computationally efficient maximum likelihood (ML) estimation algorithm is employed to compute parameters and the hidden state of each coefficient is revealed by maximum a posteriori (MAP) estimation. Experimental results of natural images are provided to evaluate the algorithm. For noisy images, the method can extract edges and remove noise simultaneously. The method can be used together with edge-based image processing techniques to improve subjective and objective quality of noisy images. In addition, the proposed model has the potential to be an efficient multi-scale statistical modeling tool for other image or video processing tasks. / 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. / Zhang, Renqi. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 109-113). / 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.viii / Publications --- p.x / Nomenclature --- p.xii / Contents --- p.xviii / List of Figures --- p.xxi / List o f Tables --- p.xxiii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation and Objectives --- p.1 / Chapter 1.2 --- Thesis Outline --- p.4 / Chapter 2 --- Image/Video Coding Standard --- p.5 / Chapter 2.1 --- Image Coding Standard JPEG --- p.5 / Chapter 2.1.1 --- JPEG Codec --- p.6 / Chapter 2.1.2 --- Block-based Discrete Cosine Transform (DCT) --- p.7 / Chapter 2.1.3 --- Quant ization and Entropy Coding --- p.9 / Chapter 2.1.4 --- Decoding --- p.11 / Chapter 2.1.5 --- Effects of JPEG Compression --- p.12 / Chapter 2.2 --- Video Coding Standard H.264/AVC --- p.12 / Chapter 2.2.1 --- H.264 Codec --- p.14 / Chapter 2.2.2 --- Inter Prediction --- p.15 / Chapter 2.2.3 --- Intra Prediction --- p.15 / Chapter 2.2.4 --- Transform and Quantization --- p.17 / Chapter 2.2.5 --- Deblocking Filter --- p.19 / Chapter 2.3 --- Conclusion --- p.21 / Chapter 3 --- Image Postprocessing --- p.22 / Chapter 3.1 --- Introduction --- p.22 / Chapter 3.2 --- The Proposed Non-local KUAN's Filter in the DCT Domain --- p.24 / Chapter 3.2.1 --- LMMSE Filter in the DCT Domain --- p.25 / Chapter 3.2.2 --- The solution of the LMMSE Filter --- p.26 / Chapter 3.2.3 --- Non-local Parameter Estimation --- p.29 / Chapter 3.2.4 --- Investigation on Assumptions 1 and 2 --- p.29 / Chapter 3.3 --- Image Postprocessing by the Dual Non-local Kuan's Filter --- p.34 / Chapter 3.3.1 --- DNLK Filter --- p.35 / Chapter 3.3.2 --- OCDNLK Filter --- p.36 / Chapter 3.4 --- Experimental Results and Analysis --- p.37 / Chapter 3.4.1 --- Experiments on Three Test Quantization Tables --- p.37 / Chapter 3.4.2 --- Experiment al Setting --- p.38 / Chapter 3.4.3 --- Experiment al Results and Comparison with State-of-the-Art Methods --- p.38 / Chapter 3.4.4 --- Postprocessing on JPEG Coded Images --- p.40 / Chapter 3.4.5 --- Complexity Analysis --- p.40 / Chapter 3.5 --- Conclusion --- p.41 / Chapter 4 --- Improved Non-local Kuan's Filter using a Gaussian Scale Mixture --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.1 --- Non-local Kuan's filter in the DCT domain --- p.50 / Chapter 4.1 --- Improved Non-local Kuan's Filter using a Guassian Scale Mixture --- p.52 / Chapter 4.3.1 --- Gaussian Scale Mixture Model --- p.52 / Chapter 4.3.2 --- Computation of Bayes Least Square Estimator --- p.55 / Chapter 4.4 --- Experimental Sett ings and Results --- p.56 / Chapter 4.5 --- Conclusion --- p.57 / Chapter 5 --- Quadtree-based Non-local Kuan's Filtering in Video Compression --- p.59 / Chapter 5.1 --- Introduction --- p.59 / Chapter 5.2 --- The Proposed Loop Filters --- p.62 / Chapter 5.2.1 --- Non-local Kuan's Filter --- p.62 / Chapter 5.2.2 --- The NLK Loop Filter --- p.65 / Chapter 5.2.3 --- The Overcomplete NLK Loop Filter --- p.67 / Chapter 5.2.4 --- Use of t he Quant ization Constraint Set (QCS) --- p.69 / Chapter 5.2.5 --- Performance of t he NLK and OCNLK Loop Filters for Video Coding --- p.70 / Chapter 5.2.6 --- The Proposed Quadtree-based NLK and OCNLK Loop Filters --- p.74 / Chapter 5.3 --- Experimental Result s and Analysis of QNLK and QOCNLK Loop Filters --- p.76 / Chapter 5.3.1 --- Experiment al Results of QNLK and QOCNLK Loop Filters --- p.76 / Chapter 5.3.2 --- Computational Complexity Analysis --- p.78 / Chapter 5.4 --- QNLK and QOCNLK Postprocessing Filters --- p.82 / Chapter 5.4.1 --- Experimental Result s and Analysis ofQNLK and QOCNLK Postprocessing Filters --- p.84 / Chapter 5.5 --- Conclusion --- p.85 / Chapter 6 --- Image Edge Detection using 3-D Hidden Markov Model based on the Non-decimated Wavelet --- p.88 / Chapter 6.1 --- Introduction --- p.88 / Chapter 6.2 --- Three-dimensional HMM based on the Non-decimated Wavelet (3-D N-WHMM) --- p.90 / Chapter 6.2.1 --- Hidden Markov Model (HMM) --- p.90 / Chapter 6.2.2 --- 3-D Hidden Markov Model (3-D HMM) --- p.91 / Chapter 6.2.3 --- Construction of the 3-D NWHMM --- p.92 / Chapter 6.2.4 --- Probabilistic Model for Individual Wavelet Coefficient --- p.92 / Chapter 6.2.5 --- Training Paramet ers and Searching for Hidden States --- p.94 / Chapter 6.3 --- Experimental Results and Analysis --- p.96 / Chapter 6.3.1 --- The algorithm implementation --- p.96 / Chapter 6.3.2 --- Comparisons with Canny and two multi-scalet echniques --- p.96 / Chapter 6.3.3 --- Experimental results of noisy images --- p.98 / Chapter 6.4 --- Conclusion --- p.98 / Chapter 7 --- Conclusions and Future Work --- p.103 / Chapter 7.1 --- Contributions of The Thesis --- p.103 / Chapter 7.2 --- Future Work and Research Directions --- p.104 / Chapter A --- Appendix A --- p.107 / Chapter A.1 --- Mathematical Derivations of equation (4.6) --- p.107 / Bibliography --- p.109
27

A study of video transmission over explicit rate controlled network. / CUHK electronic theses & dissertations collection

January 2001 (has links)
Ngai Li. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 75-[78]). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
28

A study of the transmission of VBR encoded video over ATM networks.

January 1997 (has links)
by Ngai Li. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 66-69). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Video Compression and Transport --- p.2 / Chapter 1.2 --- Research Contributions --- p.6 / Chapter 1.2.1 --- Joint Rate Control of VBR Encoded Video --- p.6 / Chapter 1.2.2 --- Transporting VBR Video on LB Controlled Channel --- p.7 / Chapter 1.3 --- Organization of Thesis --- p.7 / Chapter 2 --- Preliminary --- p.9 / Chapter 2.1 --- Statistical Characteristics of MPEG-1 Encoded Video --- p.9 / Chapter 2.2 --- Temporal and Spatial Smoothing --- p.14 / Chapter 2.2.1 --- Temporal Smoothing --- p.14 / Chapter 2.2.2 --- Spatial Smoothing --- p.15 / Chapter 2.3 --- A Single Source Control-Theoretic Framework for VBR-to-CBR Video Adaptation --- p.16 / Chapter 3 --- Joint Rate Control of VBR Encoded Video --- p.19 / Chapter 3.1 --- Analytical Models --- p.21 / Chapter 3.2 --- Analysis --- p.27 / Chapter 3.2.1 --- Stable Region --- p.29 / Chapter 3.2.2 --- Final Value of the State Variables --- p.33 / Chapter 3.2.3 --- Peak Values of Buffer-occupancy Deviation and Image- quality Fluctuation --- p.35 / Chapter 3.2.4 --- SAE of Buffer-occupancy Deviation and Image-quality Fluc- tuation --- p.42 / Chapter 3.3 --- Experimental Results --- p.43 / Chapter 3.4 --- Concluding Remarks --- p.48 / Chapter 4 --- Transporting VBR Video on LB Controlled Channel --- p.50 / Chapter 4.1 --- Leaky Bucket Access Control --- p.51 / Chapter 4.2 --- Greedy Token-usage Strategy --- p.53 / Chapter 4.3 --- Non-greedy Token-usage Strategy --- p.57 / Chapter 4.4 --- Concluding Remarks --- p.60 / Chapter 5 --- Conclusions --- p.62 / Chapter 5.1 --- Joint Rate Control of Multiple VBR Videos --- p.62 / Chapter 5.2 --- LB Video Compression --- p.63 / Chapter 5.3 --- Further Study --- p.64 / Chapter 5.4 --- Publications --- p.65 / Bibliography --- p.65
29

Joint source-channel coding for image transmission and related topics

Xiang, Wei January 2003 (has links)
With the integration of wireless technologies and multimedia services, transmitting high quality images and video has become one of the main objectives for next generations mobile network systems. Shannon's classic separation theorem states that, under ideal conditions, source coding and channel coding can be treated separately without sacrificing any performance for the whole system. However, this theorem holds true only under ideal conditions. Practical communication systems do not meet such requirements. Therefore, joint source and channel coding may reduce distortion, as well as complexity and delay. In this thesis, different schemes of joint source-channel coding and decoding for error resilient image transmission over noisy channels are examined. Unequal error protection (UEP) is one of the techniques used in joint source and channel coding. A JPEG image is partitioned into DC components and AC components according to their respective sensitivity to channel noise. The highly sensitive DC components are better protected with a low coding rate, while the less sensitive AC components use a high coding rate. Simulation results show that the proposed UEP scheme slightly outperforms conventional equal error protection (EEP). A novel turbo diversity scheme (TDS) applied to JPEG coded images is proposed. Turbo codes have a built-in structure that is suitable for diversity techniques used to improve the quality of communications over a multi-path channel. The same image data is encoded by two separate turbo encoders and sent over two independent channels. The received data is then passed to a single turbo decoder. By utilising the built-in structure of the turbo encoder, the transmitted JPEG data encoded by a rate half code is recovered at the receiver using a more powerful rate third code yielded by the TDS. An iterative source-channel decoding scheme applied to JPEG coded images is investigated. Huffman codes used as the variable-length coding scheme in JPEG coding can be represented by an irregular VLC-trellis structure. State transition probabilities can be derived from the irregular trellis and can be used as a priori information to help iterative decoding between source and channel a posteriori probability (APP) decoders. Iterative decoding of JPEG coded images only gives a small coding gain due to the poor distance property of the original JPEG Huffman codes. We propose to replace the Huffman codes used in JPEG coding with error resilient source codes with larger free distance. After accounting for the penalty due to the increased average codeword length, the new scheme achieves a 4 dB coding gain over the conventional system for a range of SNRs. While the focus of this thesis is on joint source-channel coding, two other related topics are also examined, namely, capacity and normalisation of intersymbol interference (ISI) channels and parallel data convolutional codes. Previously published results showed a minimum Eb/N0 of -4.6 dB, 3 dB below the capacity of a flat channel, is obtained using the water-pouring capacity formulas for the 1+D channel. However, these results did not take into account that the channel power gain can be greater than unity when water-pouring is used. We present a new generic power normalization method of ISI channel frequency spectra, namely peak bandwidth normalisation, to facilitate the fair capacity comparison of various ISI channels. A final contribution presented in this thesis regards the proposed parallel data convolutional codes (PDCCs). The encoder inputs consist of the original block of data and its interleaved version. We propose a novel single self-iterative soft-input/soft-output (SISO) decoder structure for the decoding of PDCC. It has the advantage of needing only one APP decoder. Although the performance is not very encouraging, the novelty of the self-iterative idea behind the design is worth exploiting. / thesis (PhDTelecommunications)--University of South Australia, 2003.
30

Image compression using overcomplete wavelet representations for multiple description coding /

Miguel, Agnieszka C. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 129-144).

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