Optimized quantization for image subband coding

摘要

Subband coding of images, which can be seen as an extension of orthogonal transformations, has been introduced by Woods and O'Neil. In their paper, the subbands are further encoded by DPCM. In this study, it is proposed to use subband coding as a stand alone coding technique. The emphasis is put on the question of subband quantization. A methodology is proposed where the quantization steps of the subbands are computed so as to minimize a quantization noise power weighted by a sensitivity function of the eye. The methodology which is proposed is also valid for unequal size subbands.