Image and Video Compression: Current Trends and Perspectives

It is an attempt to describe briefly the state of art end prospective directions of development of image compression. The paper deals with coding of continuous-tone color still images and video captured from real world. Here, three main aspects are: lossless coding, lossy coding of still images and video coding. Some basic features of newest image compression standards are described and basic research areas are defined. The history of image data compression started probably about a half of century ago with the works on predictive coding and variable length codes. In 1960’s, advances in digital image processing stimulated research on compression that yielded marvelous results of 1980’s. This technological breakthrough resulted in efficient compression algorithms that have been standardized in early 1990’s and currently are in common use together with the improvements achieved during the last decade. These advances have brought substantial increase in efficiency of earlier basic techniques. Nevertheless, the last decade was also a period of strenuous search for new technologies of image data compression. Nowadays, image data coding is a key component of multimedia communication and storage systems. For the sake of brevity, here, we focus our attention on continuous-tone color still images and video captured from real world by use of some electronic equipment. Here, three main aspects are: • Lossless (reversible) still image coding. The original data can be restored from the coded representation with no loss of data. • Lossy (irreversible) still image coding. Decoded images only approximate the original ones. There is a tradeoff between the quality and fidelity of the restored images and compression ratio measured for the compressed representation. • Video coding. It is mostly irreversible coding of moving pictures including 3-D (stereoscopic) ones. Nevertheless image coding generally involves also compression and coding bilevel or fax images and document images containing text, handwriting, graphics and photographs.