Application of a special JBIG processor to compression of Earth observation images

摘要

Abstract: The large size is a typical feature of earthobservation images. The increasing number of bandssimultaneously available on satellites and the launchof system able to achieve a ground resolution as low asone meter is making this problem more a nd more hot.Indeed, the large size of typical images dramaticallyreduces the possibility to distribute them to a widenumber of interest parties. In the wide majority ofcases, this problem is currently tackled either byusing lossy compression schemes such as basic versionsof JPEG or by narrowing the ground extension of thepictures. Of course, both of them are unsatisfactory.Indeed, the partial loss of data may be acceptable onlyfor non-quantitative analysis while narrower picturesmay not carry all the needed informant. An alternatepossibility is the use of an efficient losslessalgorithm. Among others, JBIG has been preferred forthis purpose because it achieves very high compressionrate, overperforming the well known ZIP algorithm inthe wide majority of cases. Further advantages are dueto its progressive nature and to its availability as anITU international standard. In order to have a veryperformant syste, this algorithm has been implementedby the development of an application specificintegrated circuit designed to compress/decompresslarge volumes of data with throughput rate greater than1 Gb/min. The performances achieved by the system whendealing with typical visual and radar satellite imagesand the perspective applications are described. !3