Sub-band coding of images
This paper presents an extension of sub-band coding to two-dimensions with particular application to images. We employ a 16 band decomposition using a tree structure of separable quadrature mirror filters and decimators. The sub-bands are encoded using DPCM with bits allocated to approximately minimize the mean-square error. A block-adaptive variant is also presented. A limited SNR comparison shows adaptive sub-band coding to outperform the adaptive discrete cosine transform and two types of vector quantizers.