Image processing apparatus and method for format conversion

摘要

A signal processing apparatus converts interlaced 4:2:2-format video signals including a luminance component and two chroma components into interlaced 4:2:0 format video signals. A downsampling low-pass filter has such a group delay that a modulo-1 remainder of the group delay at frequency É=0 is substantially equal to 0.25. The downsampling low-pass filter is designed together with an associated upsampling low-pass filter such that the first downsampling low-pass filter and the upsampling low-pass filter substantially satisfy perfect reconstruction filter bank condition, and such that a sum of the group delay of the first downsampling low-pass filter and a group delay of a normalized filter obtained by making the sum of all the coefficients of the upsampling low-pass filter equal to 1 is substantially equal to an integer number at frequency É=0.