VISUAL DATA-COMPRESSION FOR MULTIMEDIA APPLICATIONS

In this paper, the compression of visual information in the framework of multimedia applications is discussed To this end, major approaches to compress still as well as moving pictures are reviewed. The most im portant objective in any compression algorithm is that of compression efficiency. High-compression coding of still pictures can be split int o three categories: waveform, second-generation, and fractal coding te chniques. Each coding approach introduces a different artifact at the tar-get bit rates. The primary objective of most ongoing research in t his field is to mask these artifacts as much as possible to the human visual system. Video-compression techniques have to deal with data enr iched by one more component. namely, the temporal coordinate. Either c ompression techniques developed for still images can be generalized fo r three-dimensional signals (space and time) or a hybrid approach can be defined based on motion compensation. The video-compression techniq ues can then be classified into the following four classes: waveform, object-based, model-based, and fractal coding techniques. The aim of t his paper is to provide the reader with a tutorial on major visual dat a-compression techniques and a list of references for further informat ion on the details of each method.