Impact of recent compression/decompression technologies in video distribution systems

The authors present the fundamental principles, techniques, and algorithms for compression/decompression currently available in the marketplace (JPEG/CCITT/MPEG) and a potentially superior method for cockpit video distribution applications under investigation. It is noted that JPEG (Joint Photographic Experts Group), CCITT (International Consultative Committee for Telephone and Telegraph), or MPEG (Motion Picture Experts Group) alone will not solve the myriad of issues that must be addressed before digital imagery will be fully integrated within next generation cockpit high definition video distribution systems. After careful consideration of each standard´s capabilities and original objectives, it is found that each group provides extremely relevant techniques and foundation to their accomplishments, but that none is necessarily ideal for avionic applications. JPEG imposes compression ratio limitations to maintain quality levels. CCITT limits image resolution, allows a 150-ms latency, and is geared toward limited motion applications. In MPEG´s attempt to overcome the CCITT deficiencies, additional hardware complexity is required. The MPEG standard supports extended motion search and is optimized for motion-intensive video applications at the expense of the high compression ratios achievable by the CCITT approach. The most complex implementation issue that exists is being able to achieve the high pixel rates required at moderate complexity, weight, size, and power. While most silicon vendors have been struggling with the lower resolution H.261 and MPEG real-time implementation, the wavelet transform may allow a very acceptable low complexity solution