摘要
人们利用便携终端通过IP网络传输视频信息的需求越来越多，为了实现这个目标，有两个问题需要解决：1．编码方法要简单高效。方法简单，容易用硬件实现，且功耗低；方法高效，可以有效的利用网络带宽实时传输视频；2．编码要有好的鲁棒性，以适应IP网络的传输特性，在出现丢包的情况下，能够实时恢复出较好的图像质量。
针对上述两个问题，本文提出基于3D-DCT的多描述编码方案，它由分块、3D-DCT变换、量化、MDSQ编码、RLE编码和熵编码等部分组成。3D-DCT变换编码，没有运动补偿，运算复杂度低，通过优化量化表和扫描顺序，使3D-DCT达到了令人满意的压缩比和图像质量。多描述编码把信源变成多个描述，每个描述都可以恢复出一定质量的信源，降低了某个描述丢失所带来的损失，提高了编码的鲁棒性。
实验仿真表明3D-DCT和多描述相结合的视频编码方案，在简单高效的同时具有很强的抗误码能力，很好的解决了视频传输在便携终端上应用的问题。
The need of transmission of video via IP networks becomes more and more. In order to achieve this goal, two problems should be solved. Firstly, the coding method should be simple and high efficiency. Simple method can be implemented by hardware easily, and requires lower power. High efficiency can decrease network bandwidth needed for communication. Secondly, the coding is robust, i.e, it is fit for transmission via IP networks. Even when some packets are lost during transmission, acceptable quality of video can still be reconstructed.
To solve the above-mentioned two problems, this paper proposes a multiple description video coding method based on 3D-DCT and MDSQ. The system consists of several parts: video volume formation, 3D-DCT, MDSQ, RLE coding and entropy coding and so on. 3D-DCT is a symmetrical transform so the encoder and the decoder has similar computational complexity. There is no motion compensation in the proposed scheme, so the method is simple and can be easily implemented in hardware. Through the optimization of the quantization volume and scanning order, the 3D-DCT based video coding scheme can obtain satisfactory results both in compression ratio and in PSNR. Multiple description coding divides the source information into several descriptions, each description could reconstruct acceptable source information, and reduced the loss caused by the lost of some descriptions, and improve the reliability of the video coding method.
Experiment results show that the 3D-DCT based multiple description coding scheme has a finer robustness while being simple and highly efficient. The scheme is suitable for video transmission on portable terminal.
引文
[1] [美]R．C．冈萨雷斯，P．温茨著(李叔梁等译)，《数字图像处理》，科学出版社，1981
[2] [美]A．罗申费尔德，A．C．卡克著(余瑛林等译)，《数字图像处理》，人民邮电出版社，1982
[3] 荆仁杰，叶秀清等，《计算机图像处理》，浙江大学出版社，1992
[4] 赵荣椿，赵忠明等，《数字图像处理导论》，西北工业大学出版社，1995
[5] 徐建华，《图像处理与分析》，科学出版社，1992
[6] 刘政凯，翟建雄，《数字图像恢复与重建》，中国科技大学出版社，1990
[7] 余英林著，《数字图像处理与模式识别》，华南理工大学出版社，1990
[8] Aggelos K.Katsaggelos, "Recent Trends in Image Restoration and Enhancement Techniques", Proceedings of IEEE Asia Pacific Conference on Circuits and Systems'96, pp458-459, 1996
[9] Pratt, "Digital Image Processing", New York: John Wiley&Sons, 1978
[10] 姚庆栋，毕厚杰，王兆华，徐孟侠，《图像编码基础》，浙江大学出版社，1993
[11] 吴乐南编著，徐孟侠审，《数据压缩的原理与应用》，电子工业出版社，1995
[12] Yao Wang and Qin-fan Zhu, "Error Control and Concealment for Video Communication: A Review", Proceedings of IEEE, 1998, 86(5):974-997
[13] Yao Wang, Sephan Wenger, Jiangtao Wen, et al. "Error Resilience Video Coding Techniques: Real-Time Video Communications over Unreliable Networks", IEEE Signal Processing Magazine, 2000,17(4):61-82
[14] Jie Song and K. J. Ray Liu. "A Data Embedded Video Coding Scheme for Error-Prone Channels", IEEE Trans. On Multimedia, 2001, 3(4):415-423.
[15] Bernd Girod and Niko Farber. "Feedback-Based Error Control for Mobile Video Transmission", Proceedings of the IEEE, Oct. 1999, 87(10): 1707-1723.
[16] Wai-tian Tan and Avideh Zakhor. "Real-time Internet Video.Using Error Resilient Scalable Compression and TCP-Friendly Transport Protocol", IEEE Trans. On Multimedia, 1999, 1(2): 172-186.
[17] John D. Villasenor, Ya-Qin Zhang, and Jiangtao Wen. "Robust Video Coding Algorithms and Systems". Proceedings of the IEEE, Oct. 1999, 87(10): 1724-1733.
[18] Tien-Hsu Lee and Pao-Chi Chang. "Error Robust H.263 Video Coding with Video Segment Regulation and Precise Error Tracking". IEEE Trans. On Communication, 2001, E84-B(2):317-324.
[19] Iole Moceagatta, Salma Soudagar, Jie Liang, et al. "Error-Resilience Coding in JPEG-2000 and MPEG-4". IEEE Journal on Selected Areas In Communications, 2000, 18(6): 899-914.
[20] W.-M. Lam and A. Reibman. "An error concealment algorithm for images subject to channel errors". IEEE Trans. Image Processing, May 1995:533-542
[21] ITU Telecom. Standardization Sector of ITU. Video Coding for Low Bit Rate Communication. ITU-T Recommendation H.263 Version2, Jan. 1998.
[22] Klaus Stuhlmüller, Niko Frber, Michael Link, "Analysis of Video Transmission
over Lossy Channels". IEEE Journal on Selected Areas In Communications, 2000, 18(6): 1012-1032.
[23] Peter Cherriman, Choong Hin Wong, and Lajos Hanzo. "Turbo- and BCH-Coded Wide-Band Burst-by-Burst Adaptive H.263-Assisted Wireless Video Telephony". IEEE Trans. On Circuits and Systems for Video Tech., 2000, 10(8): 1355-1363.
[24] Peter Cherriman, B. L. Yeap, and Lajos Hanzo. "Turbo-Equalised H.263-Based Video Telephony for GSM/GPRS". In Proc. ICC2001, Helsinki, Finland, June 2001.
[25] V.K. Goyal. "Multiple Description Coding: Compression Meets the Netwrok" IEEE Signal Processing Magazine. Sep 2000. pp: 74-93.
[26] Hang Liu and Magda EI Zarki. "Performance of H.263 Video Transmission over Wireless Channels Using Hybrid ARQ". IEEE Trans. On Circuits and Systems for Video Tech., 1997, 15(9): 1775-1786.
[27] Raymond WestWater, Borko Furht, "Real-time Video Compression", Kluwer Academic Plulishers, Boston, 1997.
[28] W.H. Chen, C.H. Smith, and S.C. Fralick, "A Fast. Computational Algorithm for the Discrete Cosine Transform", IEEE Trans. Commun, Vol.COM-25, pp. 1004-1009, Sep, 1997.
[29] B.G. Lee, "A New Algorithm to Compute the Discrete Cosine Transform", IEEE Trans. Acoust, Speech, and Signal Process., Vol.ASSP-32, No.6, pp. 1243-1245, Dec. 1984.
[30] J.Makhoul, "A Fast Cosine Transform in One and Two Deimensionsm", IEEE Trans. Acoust, Speech, and Signal Process., Vol.ASSP-28, pp.27-34, Dec. 1980
[31] 韦岗，邱伟著，《现代信号处理理论与技术》，华南理工大学出版社，1994
[32] 黎洪松著，《数字视频技术及其应用》，清华大学出版社，1998
[33] 胡广书著，《数字信号处理—理论、算法与实现》，清华大学出版社，1998
[34] M.C. Lee, Raymond K.W. Chan & D.A. Adjeroh, "Quantization of 3D-DCT Coefficients and Scan Order for Video Compression", Journal of Visual Communication and Image Representation, Vol. 8, No. 4, pp.405-422, December 1997.
[35] Dong Lin, "Real-time Voice Transmissions over the Internet", The Thesis for the Degree of Master Science in Electrical Engineering in the Graduatae College of University of Illinois at Urbana-Champaign, 1999
[36] S.E. Miller, "New transmission configuration", Bell Labs, lab notebook #55637, May 1978.
[37] S.E. Miller, "Fail-safe transmission without standby facilities", Bell Labs, Tech.Rep. TM80-136-2, Aug. 1980.
[38] D.O. Reudink, "The channel splitting problem with interpolative coders", Bell Labs, Tech. Rep. TM80-134-1, Oct. 1980.
[39] H.S. Witsenhausen, "An achievable region for the breakdown degradation problem with multiple channels", Bell Labs Tech. Rep. TM81-11217-3, Jan. 1981.
[40] H.S. Witsenhausen and A.D. Wyner, "Source coding for multiple descriptions", Bell Syst. Tech. J., vol. 60, no. 10, pp.2281-2291, Dec. 1981.
[41] V.A. Vaishampayan. "Design of multiple description scalar quantizers", IEEE
Trans.Inform.Theory, vol.39, pp.821-834, May 1993.
[42] S.D. Servetto, V.A. Vaishampayan, and N.J.A. Sloane, "Multiple Descriptions Lattice Vector Quantization", in Proc. IEEE Data Compression Conf.,Snowbird, UT, Mar. 1999, pp. 13-22.
[43] V.A. Vaishampayan, N.J.A. Sloane, and S.D. Servetto, "Multiple description vector quantization with lattice codebooks: Design and analysis", IEEE Trans. Inform. Theory, vol.47, pp.1718-1734, 2001.
[44] V.K. Goyal and J. Kovacevic, "Generalized Multiple Description Coding with Correlating Transforms", IEEE Trans.Inform.Theory, vol.47, pp..2199-2224, Sep 2001
[45] V.K Goyal, J. Kovaeevie, and M. Vettedi, "Multiple Description Transform Coding: Robustness to Erasures Using Tight Frame Expansions", Proc. IEEE Int. Symp. On Information Th. (Cambridge, MA), August 1998.
[46] V.K. Goyal, J. Kovacevie, and J.A. Kelner, "Quantized Frame Expansions with Erasures", Applied and Computational Harmonic Analysis, vol. 10, no.3, pp.203-233, May 2001.
[47] T. Berger, "Optimum Quantizers and permutation codes", IEEE Trans. Inform. Theory, vol. IT-18, pp. 485-497, Nov,1972
[48] N. Farvardin and J.W. Modestino, "Optiomum Quantizer Performance for a Class of Non-Gaussian Memoryless Sources", IEEE Trans. Inform. Theory, vol. IT-30, pp.485-497, May 1984.
[49] P.A. Chou, T. Lookabaugh, and R.M. Gray, "Entropy-Constrained Vector Quantization", IEEE Trans. Acoust, Speech, Signal Processing, vol.37, pp.31-42, Jan 1989
[50] Michael T.Orchard, Yao Wang, Vinay Vaishampayan,Amy R.Reibman, "Redundancy Rate-Distortion Analysis of Multiple Description Coding Using Correlatiing Transforms", in IEEE Image Processing, vol. 1, 26-29 pp.608-611, Oct. 1997.