Pre- and Post-Filtering for Block-Based Image and Video Communication Systems

本研究涉及基于块的图像/视频通信系统中沿数据块边界的预滤波和后滤波集成框架的研究和开发。该框架可以看作是对JPEG和MPEG中传统的块DCT编码方法的推广和显著改进。该研究特别针对低复杂性的图像/视频编码和通信算法或系统，用于资源受限、速度关键和无线手持设备的实时应用。该研究预计将对实际的信号处理、编码和通信系统产生重大影响。通过考虑块间空间相关性和基于局部信号内容动态调整算子，大大提高了编码效率。在解码器处，增强了感知重构的质量。阻塞伪影通过沿块边界的积极后滤波得到缓解，而振铃伪影通过自适应改变算子的大小而大大减少。通过空间扩展信息和基于通信环境和接收到的相邻数据动态切换插值后置滤波器，提高了噪声信道环境下的鲁棒性和数据恢复能力。最后，在实际操作方面，小型本地运算符非常适合并行计算和快速、vlsi友好、可能无乘数的实现。现有的基于块的基础设施可以保持完整，因为预处理/后处理在空间域之外进行。研究者探索了能够与目前在网络和存档数字图书馆中可用的大量JPEG和MPEG比特流保持兼容性的预处理/后处理操作符。-------------------工作水平声明：在推荐的支持水平下，项目负责人将尽一切努力满足项目的原始范围和工作水平。

This research involves the study and development of an integrated framework of pre- and post-filtering along the data block boundaries in block-based image/video communication systems. The novel framework can be thought of as a generalization of and provides a significant improvement for the traditional block DCT coding approach in JPEG and MPEG. The investigation is particularly geared toward low-complexity image/video coding and communication algorithms or systems in resource-constrained, speed-critical, and real-time applications for wireless hand-held devices.The research is expected to have a significant impact on practical signal processing, coding and communication systems. Coding efficiency is greatly improved by taking into account inter-block spatial correlation and by adapting operators dynamically based on local signal contents. At the decoder, perceptual reconstruction quality is enhanced. Blocking artifacts are mitigated with aggressive post-filtering along the block boundaries whereas ringing artifacts are greatly reduced by adaptively varying the operator size. Robustness and data recovery capability in noisy channel environments are also improved by spreading information spatially and by dynamically switching interpolative post-filters based on the communicating environment and the neighboring data received. Finally, on the practical aspect, small local operators lend themselves nicely to parallel computing, and fast, VLSI-friendly, possibly multiplierless, implementations. Existing block-based infrastructure can be kept intact since pre-/post-processing operates outside in the spatial domain. The investigator explores pre-/post-processing operators that can maintain compatibility with the huge collection of JPEG and MPEG bit-streams currently available on the web and in archiving digital libraries.-------------------Level of Effort Statement:At the recommended level of support, the PI will make every attempt to meet the original scope and level of effort of the project.