Fast DCT block smoothing algorithm
Rensheng Horng, Albert J. Ahumada · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1995
Image compression based on quantizing the image in the discrete cosine transform (DCT) domain can generate blocky artifacts in the output image. It is possible to reduce these artifacts and RMS error by adjusting measures of block edginess and image roughness, while restricting the DCT coefficient values to values that would have been quantized to those of the compressed image. This paper presents a fast algorithm to replace our gradient search method for RMS error reduction and image smoothing after adjustment of DCT coefficient amplitude.