Video Bandwidth Compression System.

The Avionics Laboratory AFWALAA is presently pursuing the development of equipment that will provide jam resistant protection of realtime video imagery transmission. A critical component of these jam resistant data link systems is the video bandwidth compression unit, which must meet stringent constraints imposed by vehicle limitations, while maintaining sufficient image fidelity for a remote operator to effectively accomplish the mission. A two-dimensional discrete cosine transform 2D-DCT algorithm was selected with a sub-picture block size of 8 x 8 pixels. A hardwarefirmware approach was used. CMOSSOS adders, multipliers, and AD converter were coupled with bulk CMOS and LS-TTL digital logic to get the lowest power design. Video is sampled at 10 MHz and pipeline processed at 1 MHz. Use of an input frame grabber was disallowed so that the VBC system used a stripe technique in which samples are taken from each TV field in realtime. Hardware system test results have confirmed that the performance of the 2D-DCT algorithm is excellent and easily implemented with little or no artifacts at 1 to 2 bitspixel. At 0.5 bitspixel the picture is poor as expected.