摘要
It takes a long computer time for 3-D convolution to accomplish 3-D ideal band-pass filtering according to conventional method. The author proposed that 2-D fan filtering or directional filtering can be accomplished by using Hilbert transform. This note introduces accomplishment of some kinds of ideal band-pass filtering by Hilbert transform, and then the 3-D convolution becomes a finite number of 1-D convolution series-parallel connected.
