<title>Three-dimensional motion-compensated subband coding</title>

Abstract

Three-dimensional (3-D) frequency coding is an alternative approach to hybrid coding concepts used in nowaday standards. However, the lack of Motion Compensation (MC) techniques is a drawback in 3-D coders when compared to hybrid MC coding. This paper presents a 3-D Subband Coding (SBC) scheme with MC, which is based on a separable structure. Motion-compensated 2-tap Quadrature Mirror Filters (QMFs) are employed for subband decomposition along the temporal axis, and a parallel Time Domain Aliasing Cancellation (TDAC) filter bank is used for decomposition in the spatial domain. The temporal axis analysis and synthesis operations are performed in a cascade structure. A special substitution technique, which occasionally places unfiltered values into the temporal lowpass band at any stage of cascade, guarantees perfect reconstruction synthesis in the case of a non- uniform Motion Vector Field (MVF) with full-pel MC accuracy. With sub-pel accuracy, though coding efficiency is higher, perfect reconstruction is no longer guaranteed. Lattice Vector Quantization (LVQ) has been employed to encode the subband samples. In contrast to hybrid coders, it is straightforward to perform quantization with spatio-temporal perceptual weighting. Coding results are presented, which show that standard hybrid coding concepts are outperformed by up to 4 dB with the 3-D MC-SBC/VQ coder.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.