Combining DCT and subband coding into an intraframe coder

摘要

The advent of broadband digital networks will make it possible to transmit high quality digital television. Subband coding is a very interesting coding scheme as it accommodates a transmission quality that can flexibly adapt to the available channel capacity. Subband coding (SBC) and block cosine-transform techniques have already been used together, but only to code the low-pass image. Residual spatial correlation present in higher frequencies bands has only partially been taken care of. This paper presents the results obtained with a simulated coder in which DCT is used in all bands where expected spatial correlation is high enough. The use of a pyramid vector quantizer is proposed. Results are good and compare favourably with other results published in the literature.