A study on perfect reconstructive subband coding

The authors present a subband coding scheme which has the possibility of distortion-free encoding. The coding scheme, which divides input signals into frequency bands, lends itself to parallel implementation. Computer simulation is conducted using high-quality HDTV component signals. Quadrature mirror filters (QMFs) and short-kernel subband filters are compared in terms of entropy (bit-per-pel) and signal-to-noise ratio. Simulation results show that the short-kernel filters can reduce the entropy while maintaining the original picture quality. The number of subband-signal levels was found to be increased. Reduction of the number of signal levels by transformation during the filtering process is studied. From this study, new architectures for short-kernel filters are developed which can reduce the entropy of subband signals better than conventional two-tap filters