A study on estimating coding gain of pyramid-type non-orthogonal subband filters
Yasunari Yokota, Akira Iwata, Yukio Yoshida · Electronics and Communications in Japan (Part III Fundamental Electronic Science) · 1999
In coding intended for nonreciprocal information compression, it is required to attain a high compression rate and minimized error of the restored signal. The coding gain is the rate of error reduction when the bit error rate is kept constant before and after applying orthonormal transform, such as the discrete cosine transform or orthogonal wavelet transform. This has been used as a quantitative measure of coding performance. On the other hand, the coding gain has been similarly formulated even in non-orthogonal subband coding such as is used for the design of subband filters and for the determination of the optimum distribution of quantization error in each subband. In this paper, we point out that an approximation is included in the coding gain estimation equation for the pyramidal non-orthogonal subband filters used to date. By comparing the estimated coding gains with and without the approximation, the coding gain estimation error produced by the approximation is evaluated. For the pyramidal subband filter based on SSKF, the estimated error of the coding gain produced by the approximation is about 0.1 dB. © 1998 Scripta Technica, Electron Comm Jpn Pt 3, 82(1): 51–57, 1999