Document and Image Compression

Description

Still image coding is one of the oldest research topics in the image processing field. Activity in this area has spanned the last four decades, producing a huge volume of scientific literature and an innumerable amount of algorithms and techniques, each with their own merits and drawbacks. Starting from the mid-1980s, an intense standardization activity has been carried out, leading to the release of the worldwide popular JPEG standard in 1992. Since then, the JPEG format has reached an ubiquitous diffusion, becoming the privileged means to exchange images stored in digital format. Along with JPEG, oilier coding standards have been developed, like the JBIG standard, just to mention one, that meet the requirements set by particular applications. Spurred by new advances in image processing and (lie availability of increasing computational power, a new standardization activity began in the mid- 1990s that resulted in the release of two new coding standards: the JPEG-LS and JPEG 2000. Image coding is still a mature research field, leading one to assume that little room exists for new significant advances. In this framework, a question naturally arises: Is image coding research still worth it? As strange as it may seem, the answer is definitely yes. Tire reasons for such an answer are rather simple and are basically the same as those that spurred the research in the last decades: The computing power made available by technological advancements is continuously increasing, hence making it possible for the development of new approaches that were unfeasible until a few years ago. At the same time, new image representation tools are being developed whose exploitation for image coding looks particularly promising. Finally, new application areas are appearing that call for the development of ad hoc image coding algorithms.