PROGRESSIVE CONTENT-BASED SHAPE COMPRESSION FOR RETRIEVAL OF BINARY IMAGES

This paper deals with content-based compression of binary-shape images . The proposed method is based on a polygonal approximation of the sha pe contours. A well-known approximation algorithm, from computer visio n applications such as shape analysis and boundary pattern matching, i s adapted to achieve a progressive representation. The resulting vario us levels of shape quality are encoded, from a coarse representation f or fast browsing up to a lossless representation for final rendering. In order to perform efficient compression of the progressive shape inf ormation, discrete geometrical constraints inherent to the image grid quantization are exploited. While the proposed scheme offers a content -based description (shape boundary as opposed to bitmap blocks) togeth er with a quality scalable representation, it remains comparable, in t erms of compression efficiency, with state of the art shape coding met hods that do not combine such functionalities. (C) 1998 Academic Press .