联合信源信道编码方法的研究
摘要
联合信源信道编码(JSCC)就是兼顾信源编码和信道编码，两种编码在彼此不独立的情况下设计和运行，依靠通信系统各个部分的联合优化，使通信系统达到整体上的最优。本文主要介绍了作者在联合信源信道编码方面所做的一些研究工作。重点研究了基于信道不等差错保护的联合信源信道编码方案和基于帧内宏块刷新率(β)的联合信源信道编码方案。
本文首先对与信源信道联合编码方案相关的一些必要背景知识作了简要介绍。然后，对基于RCPC不等差错保护的信源信道联合编码的设计方法进行了深入的研究。研究中指出，信源编码后的码流均可按各部分的重要性级别分类，各部分受信道误码的干扰程度不同可以采用不同的信道保护方案。本文采用了一种可生成多码率码的特殊的删余卷积码——RCPC码作为信道编码技术，以实现不等差错保护机制(UEP)。实验证明此方法要比采用同等差错保护机制(EEP)得到更佳的图像重建性能。
本文在分析基于不等差错保护联合方案的不足之后，进而详细研究了另一种基于帧内宏块刷新率(β)的联合方案。此方案综合考虑了通信系统各个环节对整体性能的影响，给出了信源编码的率失真预测模型(D_S)和信道编码的统计模型(D_C)，由D=D_S+D_C得端到端的失真模型。针对此模型本文在最佳刷新率β的选取上以及帧内宏块位置的选择上给出了自己的改进方法：采用数学求极值的方法计算端到端失真最小情况下的最佳刷新率β；引入宏块运动复杂度的概念，并以此判断当前宏块的编码模式。实验结果表明：经本文改进后端到端失真模型的效率大大提高，编码后图像信噪比(PSNR)也较原始方法有明显提高，恢复图像质量也得到了明显的改善。
Joint source channel coding (JSCC) method considers both source coding and channel coding which are designed and run independently. It optimizes different parts of communication system jointly to get the integrated optimization. Jointing source channel coding scheme based on unequal error protected and intra MB update (β) are investigated in this paper.
Firstly, the paper gives a brief overview of the necessary background knowledge involved in designing JSCC scheme. Then the JSCC scheme based on RCPC unequal error protected is investigated. It shows that the compressed bit-streams can be classified according to their importance property. Each part of bit-streams can be protected by using different channel coding because they are influenced differently in channel. Unequal error method is done. Rate compatible punctured convolutional code—RCPC is adopted as the channel coding to carry out the UEP. The experimental results show that this scheme can get higher picture reconstructed performance than that of using equal error protected method (EEP).
After analyzing disadvantages of the jointing scheme based on UEP, another joint scheme based on the update of intra MBs (β) is investigated. In this scheme, influence coming from different parts of communication system is considered, then the source coding rate-distortion estimated model (D_s) and channel coding statistical model (D_c) are got. Finally the end to end distortion model D = D_s + D_c is got. Based on this estimated model, new algorithms in the selection of optimal intra MB update rate β and the selection of intra MBs' position are proposed in this paper. In order to minimize the end-to-end distortion, optimal β is obtained by using the mathematic method in this paper. Then according to the MB's activity complexity, the coding mode of current MB is fixed on. Experimental results show that the improved algorithms can increase the PSNR more than the original scheme. Moreover, the reconstructed picture qualities are also better than before.
本文首先对与信源信道联合编码方案相关的一些必要背景知识作了简要介绍。然后，对基于RCPC不等差错保护的信源信道联合编码的设计方法进行了深入的研究。研究中指出，信源编码后的码流均可按各部分的重要性级别分类，各部分受信道误码的干扰程度不同可以采用不同的信道保护方案。本文采用了一种可生成多码率码的特殊的删余卷积码——RCPC码作为信道编码技术，以实现不等差错保护机制(UEP)。实验证明此方法要比采用同等差错保护机制(EEP)得到更佳的图像重建性能。
本文在分析基于不等差错保护联合方案的不足之后，进而详细研究了另一种基于帧内宏块刷新率(β)的联合方案。此方案综合考虑了通信系统各个环节对整体性能的影响，给出了信源编码的率失真预测模型(D_S)和信道编码的统计模型(D_C)，由D=D_S+D_C得端到端的失真模型。针对此模型本文在最佳刷新率β的选取上以及帧内宏块位置的选择上给出了自己的改进方法：采用数学求极值的方法计算端到端失真最小情况下的最佳刷新率β；引入宏块运动复杂度的概念，并以此判断当前宏块的编码模式。实验结果表明：经本文改进后端到端失真模型的效率大大提高，编码后图像信噪比(PSNR)也较原始方法有明显提高，恢复图像质量也得到了明显的改善。
Joint source channel coding (JSCC) method considers both source coding and channel coding which are designed and run independently. It optimizes different parts of communication system jointly to get the integrated optimization. Jointing source channel coding scheme based on unequal error protected and intra MB update (β) are investigated in this paper.
Firstly, the paper gives a brief overview of the necessary background knowledge involved in designing JSCC scheme. Then the JSCC scheme based on RCPC unequal error protected is investigated. It shows that the compressed bit-streams can be classified according to their importance property. Each part of bit-streams can be protected by using different channel coding because they are influenced differently in channel. Unequal error method is done. Rate compatible punctured convolutional code—RCPC is adopted as the channel coding to carry out the UEP. The experimental results show that this scheme can get higher picture reconstructed performance than that of using equal error protected method (EEP).
After analyzing disadvantages of the jointing scheme based on UEP, another joint scheme based on the update of intra MBs (β) is investigated. In this scheme, influence coming from different parts of communication system is considered, then the source coding rate-distortion estimated model (D_s) and channel coding statistical model (D_c) are got. Finally the end to end distortion model D = D_s + D_c is got. Based on this estimated model, new algorithms in the selection of optimal intra MB update rate β and the selection of intra MBs' position are proposed in this paper. In order to minimize the end-to-end distortion, optimal β is obtained by using the mathematic method in this paper. Then according to the MB's activity complexity, the coding mode of current MB is fixed on. Experimental results show that the improved algorithms can increase the PSNR more than the original scheme. Moreover, the reconstructed picture qualities are also better than before.
引文
[1] 王辉元．数字图像通信原理与技术．北京：国防工业出版社，2000．
[2] 杨枝灵，王开．Visual C++数字图像获取、处理及实践应用．北京：人民邮电出版社，2003．
[3] Sherwood P G, Zeger K. Progressive image coding for noisy channels. IEEE Signal Processing Letter, 1997, 4(7):189-191.
[4] 生克伟，郑建宏．图像压缩编码技术及其国际标准．重庆邮电学院学报，1997．9(1)：27-30．
[5] Eim Y H, Modestino J W. Adaptive entropy-coded subband coding of image sequences. IEEE Trans. on Commun., 1993, 41(6):975-987.
[6] Basu S, Chen-Huei Chiang, Man MookChoi. Wavelets and perfect reconstruction subband coding with causal stable IIR filters. IEEE Trans. on Circuits and Systems Ⅱ:Analog and Digital Signal Processing, 1995, 42(1):24-38.
[7] Kadono S, Tahara O, Okamoto N. Encoding of color still pictures by wavelet transform and vector quantization. IEEE Electronical and Computer Engineering, 2001, 2(13):931-936.
[8] Wohlberg B, Jager G. A review of the fractal image coding literature. IEEE Trans. on Image Processing, 1999, 8(12):1716-1729.
[9] 沙丽娜，王宁章，覃团发．视频压缩编码国际标准综述．电子科技，2005．186(3)：56-61．
[10] 程念科，胡瑞敏，王中元．基于RS编码的视频差错恢复方法．计算机应用研究，2006，4：65-67．
[11] Jung S H, Kim R C, Lee Sang Uk. A hierarchical synchronization technique based on the EREC for robust transmission of H. 263 bit stream. IEEE Trans. on Circuits and Syst. for Video Technology, 2000, 10(3):433-438.
[12] Puri R, Ramchandran K, Ortega A. Joint source channel coding with hybrid FEC/ARQ for Buffer Constrained Video Transmission. IEEE Multimedia Signal Processing, 1998:567-572.
[13] Modestino J W, Daut D G. Combined source-channel coding of images. IEEE Trans. Commun., 1979, 27(11):1644-1659.
[14] Maja Bystrom, Thomas Stockhammer. Dependent source and channel rate allocation for video transmission. IEEE Trans. on Wireless Commun., 2004, 3(1):258-268.
[15] Lisimachos P K, Faisal Ishtiaq, Aggelos K K, Joint source-channel coding for motion-compensated DCT-based SNR scalable video. IEEE Trans. on Image Processing, 2002, 11(9):1043-1052.
[16] Shapiro J M. Embedded image coding using zerotrees of wavelet coefficients. IEEE Trans. on Signal Processing, 1993, 41(12):3445-3462.
[17] Said A, Pearlman W A. A new, fast, and efficient image code based on set partitioning in hierarchical trees. IEEE Trans. Circuits Syst. Video Technol, 1996, 6(3):243-250.
[18] Man H, Kossentini F, Smith M J T. Robust EZW image coding for noisy channels. IEEE Signal Processing Lett., 1997, 4(8):227-229.
[19] Gene Cheung, Avideh Zakhor. Bit allocation for joint source/channel coding of scalable video. IEEE Trans. on Image Processing, 2000, 9(3):340-356.
[20] 肖嵩，张方，吴成柯．基于小波SPIHT的联合信源信道编码新方法．计算机学报，2003，26(3)：281-286．
[21] 李平，肖嵩，吴成柯．基于MPEG-4的视频联合信源信道编码．电子与信息学报，2006，28(6)：1049-1053．
[22] Ortega A, Ramchandran K. Rate-distortion methods for image and video compression. IEEE Signal Processing Magazine, 1998, 15(11):23-50.
[23] Wang Y, Zhu Q F. Error control and concealment for video communication: A review. Proceedings of the IEEE, 1998, 86(5):974-997.
[24] Hagenauer J, Stockhammer T. Channel coding and transmission aspects for wireless multimedia. Proceedings of the IEEE, 1999, 87(10):1764-1777.
[25] Bernd Girod. Feedback-based error control for mobile video transmission. Proceedings of the IEEE, 1999, 87(10):1707-1723.
[26] Yap C W, Ngan K N, Liyanapathirana R. Error protection scheme for the transmission of H. 263 coded video over mobile radio channels. Proceedings of the SPIE International Conference on Visual Communications and Image Processing, 1997, 1:1241-1249.
[27] Talluri R. Error-resilient video coding in the ISO MPEG-4 standard. IEEE Communication Magazine, 1998, 36(6):112-119.
[28] ITU-T Recmmendation H. 263. 1996.
[29] Jerome M S. Embedded image coding using zerotrees of wavelet coefficients. IEEE Trans. On Signal Processing, 1993, 41(12):3445-3462.
[30] Jerome M. S. A fast technique for identifying zerotrees in the EZW algorithm. IEEE Trans. Coef. Acoust. Speech, Signal Processing, 1996, 3(7):1455-1458.
[31] Tenkasi V R, Sunil S G. A tutorial on CRC computations. IEEE Micro., 1988, 8(4):62-75.
[32] 张宗橙．纠错编码原理和应用．北京：电子工业出版社，2003．
[33] Hagenauer J. Rate-compatible punctured convolutional codes (RCPC codes) and their applications. IEEE Trans. on Commun., 1988, 36(4):389-400.
[34] Lee L H C. New rate-compatible punctured convolutional codes for viterbi decoding. IEEE Trans. on Commun., 1994. 42(12):3073-3079.
[35] Mooser M. Some periodic convolutional codes better than any fixed code. IEEE Trans. Inform. Theory, 1983, IT-29(5):750-751.
[36] Cote G, Kossentini F. Optimal intra coding of blocks for robust video communication over the internet. Image Commun., 1999, 9:25-34.
[37] Liao J Y, Villasenor J. Adaptive intra block update for robust transmission of H. 263. IEEE Trans. Circuits Syst. Video Technol., 2000, 10(1):30-35.
[38] Steinbach E et al. Standard compatible extension of H. 263 for robust video transmission in mobile environments. IEEE Trans. CSTV, 1997, 7(6):872-881.
[39] He Z, Cai J, Chen C W. Joint source channel rate-distortion analysis for adaptive mode selection and rate control in wireless video coding. IEEE Trans. Circuits Syst. Video Technol., 2002, 12(6):511-523.
[40] Zhang R, Regunathan S L, Rose K. Video coding with optimal inter/intra-mode switching for packet loss resilience. IEEE J. Select. Areas Commun., 2000, 18(6):966-976.
[41] He Z, Kim Y K, Mitra S K, Low-delay rate control for DCT video coding via ρ-domain source modeling. IEEE Trans. Circuits Syst. Video Technol., 2001, 11(8):928-940.
[42] He Z, Mitra S K, A linear source model and a unified rate control algorithm for DCT video coding. IEEE Trans. Circuits Syst. Video Technol., 2002, 12(11):970-982.
[43] Stuhlmuller K, Farber N, Link M et al. Analysis of video transmission over lossy channels. IEEE J. Select. Areas Commun., 2000, 18(6):1012-1032.
[44] 杨尧生，王新田，黄伟．数字视频广播卫星传送标准中的RS码．电视技术，1999，199：22-25．
[45] Huitika T R, Jeon Hyunho, Kwon Nyeongkyu et al. A concealment scheme for H. 263 coded video transported over the Internet using the RTP/UDP/IP protocol. IEEE Commun. Computers and Signal Process,, 2001, 2(28):465-468.
[46] 丁广贵，计文平，郭宝龙．Visual C++6.0数字图像编码．北京：机械工业出版社，2004．
[2] 杨枝灵，王开．Visual C++数字图像获取、处理及实践应用．北京：人民邮电出版社，2003．
[3] Sherwood P G, Zeger K. Progressive image coding for noisy channels. IEEE Signal Processing Letter, 1997, 4(7):189-191.
[4] 生克伟，郑建宏．图像压缩编码技术及其国际标准．重庆邮电学院学报，1997．9(1)：27-30．
[5] Eim Y H, Modestino J W. Adaptive entropy-coded subband coding of image sequences. IEEE Trans. on Commun., 1993, 41(6):975-987.
[6] Basu S, Chen-Huei Chiang, Man MookChoi. Wavelets and perfect reconstruction subband coding with causal stable IIR filters. IEEE Trans. on Circuits and Systems Ⅱ:Analog and Digital Signal Processing, 1995, 42(1):24-38.
[7] Kadono S, Tahara O, Okamoto N. Encoding of color still pictures by wavelet transform and vector quantization. IEEE Electronical and Computer Engineering, 2001, 2(13):931-936.
[8] Wohlberg B, Jager G. A review of the fractal image coding literature. IEEE Trans. on Image Processing, 1999, 8(12):1716-1729.
[9] 沙丽娜，王宁章，覃团发．视频压缩编码国际标准综述．电子科技，2005．186(3)：56-61．
[10] 程念科，胡瑞敏，王中元．基于RS编码的视频差错恢复方法．计算机应用研究，2006，4：65-67．
[11] Jung S H, Kim R C, Lee Sang Uk. A hierarchical synchronization technique based on the EREC for robust transmission of H. 263 bit stream. IEEE Trans. on Circuits and Syst. for Video Technology, 2000, 10(3):433-438.
[12] Puri R, Ramchandran K, Ortega A. Joint source channel coding with hybrid FEC/ARQ for Buffer Constrained Video Transmission. IEEE Multimedia Signal Processing, 1998:567-572.
[13] Modestino J W, Daut D G. Combined source-channel coding of images. IEEE Trans. Commun., 1979, 27(11):1644-1659.
[14] Maja Bystrom, Thomas Stockhammer. Dependent source and channel rate allocation for video transmission. IEEE Trans. on Wireless Commun., 2004, 3(1):258-268.
[15] Lisimachos P K, Faisal Ishtiaq, Aggelos K K, Joint source-channel coding for motion-compensated DCT-based SNR scalable video. IEEE Trans. on Image Processing, 2002, 11(9):1043-1052.
[16] Shapiro J M. Embedded image coding using zerotrees of wavelet coefficients. IEEE Trans. on Signal Processing, 1993, 41(12):3445-3462.
[17] Said A, Pearlman W A. A new, fast, and efficient image code based on set partitioning in hierarchical trees. IEEE Trans. Circuits Syst. Video Technol, 1996, 6(3):243-250.
[18] Man H, Kossentini F, Smith M J T. Robust EZW image coding for noisy channels. IEEE Signal Processing Lett., 1997, 4(8):227-229.
[19] Gene Cheung, Avideh Zakhor. Bit allocation for joint source/channel coding of scalable video. IEEE Trans. on Image Processing, 2000, 9(3):340-356.
[20] 肖嵩，张方，吴成柯．基于小波SPIHT的联合信源信道编码新方法．计算机学报，2003，26(3)：281-286．
[21] 李平，肖嵩，吴成柯．基于MPEG-4的视频联合信源信道编码．电子与信息学报，2006，28(6)：1049-1053．
[22] Ortega A, Ramchandran K. Rate-distortion methods for image and video compression. IEEE Signal Processing Magazine, 1998, 15(11):23-50.
[23] Wang Y, Zhu Q F. Error control and concealment for video communication: A review. Proceedings of the IEEE, 1998, 86(5):974-997.
[24] Hagenauer J, Stockhammer T. Channel coding and transmission aspects for wireless multimedia. Proceedings of the IEEE, 1999, 87(10):1764-1777.
[25] Bernd Girod. Feedback-based error control for mobile video transmission. Proceedings of the IEEE, 1999, 87(10):1707-1723.
[26] Yap C W, Ngan K N, Liyanapathirana R. Error protection scheme for the transmission of H. 263 coded video over mobile radio channels. Proceedings of the SPIE International Conference on Visual Communications and Image Processing, 1997, 1:1241-1249.
[27] Talluri R. Error-resilient video coding in the ISO MPEG-4 standard. IEEE Communication Magazine, 1998, 36(6):112-119.
[28] ITU-T Recmmendation H. 263. 1996.
[29] Jerome M S. Embedded image coding using zerotrees of wavelet coefficients. IEEE Trans. On Signal Processing, 1993, 41(12):3445-3462.
[30] Jerome M. S. A fast technique for identifying zerotrees in the EZW algorithm. IEEE Trans. Coef. Acoust. Speech, Signal Processing, 1996, 3(7):1455-1458.
[31] Tenkasi V R, Sunil S G. A tutorial on CRC computations. IEEE Micro., 1988, 8(4):62-75.
[32] 张宗橙．纠错编码原理和应用．北京：电子工业出版社，2003．
[33] Hagenauer J. Rate-compatible punctured convolutional codes (RCPC codes) and their applications. IEEE Trans. on Commun., 1988, 36(4):389-400.
[34] Lee L H C. New rate-compatible punctured convolutional codes for viterbi decoding. IEEE Trans. on Commun., 1994. 42(12):3073-3079.
[35] Mooser M. Some periodic convolutional codes better than any fixed code. IEEE Trans. Inform. Theory, 1983, IT-29(5):750-751.
[36] Cote G, Kossentini F. Optimal intra coding of blocks for robust video communication over the internet. Image Commun., 1999, 9:25-34.
[37] Liao J Y, Villasenor J. Adaptive intra block update for robust transmission of H. 263. IEEE Trans. Circuits Syst. Video Technol., 2000, 10(1):30-35.
[38] Steinbach E et al. Standard compatible extension of H. 263 for robust video transmission in mobile environments. IEEE Trans. CSTV, 1997, 7(6):872-881.
[39] He Z, Cai J, Chen C W. Joint source channel rate-distortion analysis for adaptive mode selection and rate control in wireless video coding. IEEE Trans. Circuits Syst. Video Technol., 2002, 12(6):511-523.
[40] Zhang R, Regunathan S L, Rose K. Video coding with optimal inter/intra-mode switching for packet loss resilience. IEEE J. Select. Areas Commun., 2000, 18(6):966-976.
[41] He Z, Kim Y K, Mitra S K, Low-delay rate control for DCT video coding via ρ-domain source modeling. IEEE Trans. Circuits Syst. Video Technol., 2001, 11(8):928-940.
[42] He Z, Mitra S K, A linear source model and a unified rate control algorithm for DCT video coding. IEEE Trans. Circuits Syst. Video Technol., 2002, 12(11):970-982.
[43] Stuhlmuller K, Farber N, Link M et al. Analysis of video transmission over lossy channels. IEEE J. Select. Areas Commun., 2000, 18(6):1012-1032.
[44] 杨尧生，王新田，黄伟．数字视频广播卫星传送标准中的RS码．电视技术，1999，199：22-25．
[45] Huitika T R, Jeon Hyunho, Kwon Nyeongkyu et al. A concealment scheme for H. 263 coded video transported over the Internet using the RTP/UDP/IP protocol. IEEE Commun. Computers and Signal Process,, 2001, 2(28):465-468.
[46] 丁广贵，计文平，郭宝龙．Visual C++6.0数字图像编码．北京：机械工业出版社，2004．