Adaptive Compression Techniques for Digital Video Communications

近年来，数字图像和视频压缩和通信领域的活动越来越多，包括诸如JPEG和MPEG等标准化工作，以及从有线电视或卫星电视到视频会议和未来多媒体服务的当前或拟议应用的数量增加。这一趋势将继续推动更高效、更适应特定传输环境的新压缩技术的发展。本研究的主要目的是为视频通信提供自适应压缩技术。自适应技术是编码器能够将其编码过程与源或信道的局部特征相匹配的技术。对于视频通信中一些令人感兴趣的问题，如比特分配和速率控制，已经获得了速率失真最优解和快速启发式近似。研究了一种近似于算术编码的标量自适应量化器。这种新技术将与网格编码量化等流行的量化技术相结合，用于实际的编码场合。研究了该方案的收敛性和渐近性。对于共享传输资源的可变信道情况，例如在ATM网络中，正在设计每个视频连接的速率约束，以实现良好的单个视频质量以及有效的整体网络利用率。这项研究是在数字视频通信研究实验室进行的，该实验室目前正在信号和图像处理研究所内建立。我们的主要教育目标是提供信号，图像和视频处理领域的教学。我们将介绍一门数字视频通信课程，旨在涵盖视频压缩的具体内容，包括相关的通信方面，并为学生提供实践经验。

The area of digital image and video compression and communications has seen growing activity in recent years, including standardization efforts such as JPEG and MPEG, and an increased number of current or proposed applications from Cable or Satellite TV to videoconferencing and future multimedia services. This trend will continue to create an incentive for new compression techniques that are more efficient as well as better adapted to the particular transmission environments. The main thrust of this research is to provide adaptive compression techniques for video communications. Adaptive techniques are those where encoders are capable of matching their encoding procedure to the local characteristics of the source or the channel. Rate-distortion optimal solutions and fast heuristic approximations are being obtained for some of the problems of interest in video communications, such as bit allocation and rate control. A novel scalar adaptive quantizer, close in spirit to arithmetic coding, is being investigated. This new technique, combined with such popular quantization techniques as trellis coded quantization, will be used in real encoding situations. Convergence and asymptotic properties of this scheme are also being studied. For variable channel situations where transmission resources are shared, as in ATM networks for instance, rate constraints for each video connection are being designed to enable good individual video quality as well as efficient overall network utilization. This research is being carried out in the Digital Video Communications research laboratory that is currently being set up within the Signal and Image Processing Institute. Our main education goal is to provide teaching in the area of signal, image and video processing. We will introduce a digital video communications course, designed to cover material that is specific of video compression including the relevant communications aspects, and to provide hands-on experience for the students .