Prefilter, compressive coding pre-processing apparatus and decompressive decoding post-processing apparatus, and compressive coding apparatus and decompressive decoding apparatus

摘要

A prefilter for use in a compressive coding apparatus, the compressive coding apparatus including the prefilter for limiting a frequency band of an input image and a compressive coding unit for implementing compressive coding of an image signal of which frequency band is limited with the prefilter, the prefilter includes: a time filter unit; a two-dimensional filter unit; and an enhancement unit. A compressive coding pre-processing apparatus provided with the prefilter includes: a prefilter unit for attenuating a diagonal frequency component of each image; a pixel skipping unit for skipping a pixel of an image signal of which diagonal frequency component is attenuated by the prefilter unit by folding back a horizontal high frequency component to a vertical high frequency component, or folding back the vertical high frequency component to the horizontal high frequency component; and a pixel space contracting unit for contracting a space of the skipped pixel.