Enhancement of IMP lossy image data compression using LCT

Summary form only given, as follows. This work addresses the lossy image data compression designed for the NASA Mars pathfinder (IMP) project. Both, mission profile and the availability of a RISC central board computer support a completely software oriented implementation of IMP lossy image data compression. One of the mission objectives is to demontfate the capability to place science payloads on the surface of Mars using a simple, reliable, low cost system within a demanding schedule. According to the cost and schedule objective a task oriented modification of the widely used Joint Photographic Expeqt Group (JPEG) standard for still image data compression was implemented as a starting version of compression software. This version has been delivered within a month after project kick-off. Subsequently extensions and improvements of performance were investigated and implemented as : (a) selection between pixel representation by 8 or 12 bit, \´item[(b)] implementation of arithmetic coding (improvement of performance), (c) implementation of "local cosine transform" (improvement of performance).