Image compression methods with distortion controlled capabilities

This paper presents a class of lossy data compression algorithms capable of encoding images so that the loss of information complies with certain distortion requirements. The developed algorithms are based on tree-structured vector quantizers (TSVQ). The first distortion controlled algorithm uses variable-size image blocks encoded on quad-tree data structures to encode efficiently image areas with different information content. Another class of distortion controlled algorithms presented is based on recursive quantization of error image blocks that represent the difference between the current approximation and the original block. The progressive compression properties of these algorithms are described. Compression/distortion performance using satellite images provided by NASA is better than that of the TSVQ algorithms at high bit rates