Subsampling Methods for Image Sequence Coding

摘要

Subsampling can be used as a method to compress digital image sequences. Thethesis begins with a look at fixed lattice subsampling systems with linear non-adaptive interpolation filters. This system is used to discuss the basics of subsampling. The interpolation process is the only aspect in this subsampling scheme open for improvement. Therefore, some alternatives for the linear non-adaptive interpolation are discussed. The restriction of a fixed subsampling lattice prevents the effective use of all the image characteristics. Thus, adaptive sampling lattices are used instead. First, the sampling lattice is adapted to the local image structure. Then, sub-Nyquist sampling and motion compensated sub-Nyquist sampling is discussed. The problem of combining transform coding with either fixed lattice subsampling or sub-Nyquist sampling is considered. Finally, the different subsampling systems are compared with each other.