A spatial frequency‐preserving post‐filter for block image coding
Yuuji Izawa · Electronics and Communications in Japan (Part I Communications) · 1991
Abstract Block image coding, based on the discrete cosine transform (DCT), is used widely for transmission and storage of images and achieves high coding efficiency. However, the blocking effect is generated at low bit rates, and it is the major cause of picture quality degradation. This paper proposes a spatial frequency‐preserving post‐filter which reduces the blocking effect efficiently without decay of spatial resolution in decoded images. By simulation, the improvement of the picture quality is verified and it is shown that the SN ratio can be improved by 0.7 to 0.9 dB.