Adaptive DCT for image-data compression

Abstract

This paper deals with the development of a coding system for image data compression based on the Discrete Cosine Transform (DCT). The aim is to integrate several methods into a single approach in order to obtain an adaptive coder characterized by higher performances. In particular, a variable blocksize scheme is used, which is based on quadtree segmentation driven by edge information. To improve data compression, DCT coefficients are then coded by a vector quantizer. Experiments have shown that the values of compression factors can be notably increased, while maintaining a good reconstruction quality.