【作者】 张钰；

【导师】 王宗义；

【作者基本信息】 哈尔滨工程大学 ， 控制理论与控制工程， 2002， 硕士

【摘要】 电子信息技术领域的数字化革命，极大地改变了人类的生活方式和工作方式，使得通信、计算机和大众传播这三大信息业务重叠、产业重组，产品推陈出新。而且电信业务也出现多元化的特点，除了传统的语音业务外，如今数据业务也成为电信业务中非常重要的一部分。传统的电话业务只是利用了语音传输，可是人们在通过语言交流的同时，还渴望能够面对面的进行交流。这就把可视电话推上了历史的舞台。但是可视电话业务在其提出十余年以来，一直未推向广泛的应用。但是国际电信联盟为了可视电话的实用化，相继提出了一系列适应电信传输信道和技术水平的可视电话和会议电视建议。但是由于可视电话中视频部分的技术难题始终是个困扰全世界视频压缩技术工作者的难题。 论文针对可视电话中最重要的视频部分的压缩编码理论和方法展开讨论。首先，针对视频图像压缩编码的必要性和可能性进行介绍，并简单地介绍了图像编码的历史和发展现状。随后，对从图像编码技术出现伊始的主要的也是成熟的图像编码方法进行了讨论和介绍，接着对现今发展最为成熟也是最行之有效的混合编码技术中的几项关键技术进行了研究和介绍。针对可视电话主要采用的ITU-T H．263协议，本文第三部分进行了详细地讨论。从该协议的基本框架、编码器解码器的主要技术和规定、码流语义结构、可选的各种改进模式的基本方法和协议规定等各个方面都进行了详细的分析和介绍。论文的第四部分，针对可视电话中最耗费计算时间，也是其中最关键的技术——离散余弦变换(DCT)和运动估计算法进行的仔细的研究，分析了当前出现的经典的实用算法，并对其原理进行了研究和介绍，并总结各种算法的特点和原理，各自提出了其的改进算法，给出了其原理介绍和实现方法，并在计算机上使用C语言进行了仿真试验，并达到了较为满意的效果，这两种算法，完全可以通过硬件得以实现并能应用到实际的可视电话的视频模块压缩算法中去。 但是论文对于可视电话的压缩编码协议中的其它部分还未进行仔细的研 哈尔滨工程大学硕士学位论文 究和实现，尤其是H．263协议提出的可选模式，对于可视电话质量的提高也 有非常重要的意义，有待于进一步的工作和研究。更多还原

【Abstract】 The digital revolution in the region of IT have changed the people’s manner of life and work, and made the communication, computer and the public communication -the three major information operation overlapped. Further more, there is a characteristic of well-rounded appeared in the telecom transaction, except for the traditional voice transaction, the data transmission has became the main part of the telecom transaction. The traditional telephone just uses the transmission of the voice, but when people intercourses with language, he also hopes to speak face to face. So all these make the videophone appeared. But since the noun of videophone appeared, the videophone has not used broadly. The ITU has brought out a serial of recommendation for the videophone, but the video part of the videophone is the most difficult question puzzled all the technicians of the world.The paper aims at the most important part-the video compression theory and technique to discuss. First, the paper introduces the importance and the feasibility of the video compression, and introduces the history and development of the video compression. Then, the paper discusses the main and ripe means of the video compression since the technique appeared, and introduces the most effective and ripest mixed coding technique. Aims at the main recommendation H.263, the third part of paper discusses particularly. The paper introduces the technique of the recommendation on the basic frame, encoder and decoder’s main technique and regulation, the syntax and semantics of the bitstream, optional coding algorithm, and etc. In the forth part of the paper, aimed the time-costest and most important technique-Discrete Cosine Transform (DCT) and Motion Estimate algorithms, paper analyses the classical and practical algorithms and introduce the theory. Then paper sum up all the algorithms character, give out the ameliorated algorithm, and simulate with the C language on the computer. These two algorithm, can be realized using hardware and can be used into the realvideophone’s video module.But the paper has not studied the other parts of the compression recommendation detailedly, especially the optional mode can improve the videophone mostly, which wait for the further research and works.更多还原