Published in Proceedings of the Sixth Annual Space Operation, Application, and Research Symposium (SOAR '92): Houston, TX, August 6, 1992.
NOTE: At the time of publication, the author Fred DePiero was affiliated with the Oak Ridge National Laboratory. Currently, August 2008, he is Assistant Dean of the College of Engineering at California Polytechnic State University - San Luis Obispo .
Oak Ridge National Laboratory has developed a real-time video transmission system for low-bandwidth remote operations. The system supports both continuous transmission of video for remote driving and progressive transmission of still images. Inherent in the system design is a spatiotemporal limitation to the effects of channel errors. The average data rate of the system is 64,000 bits/s, a compression of approximately 1000:1 for the black and white National Television Standard Code video. The image quality of the transmissions is maintained at a level that supports teleoperation of a high-mobility multipurpose wheeled vehicle at speeds up to 15 mph on a moguled dirt track. Video compression is achieved by using Laplacian image pyramids and a combination of classical techniques. Certain subbands of the image pyramid are transmitted by using interframe differencing with a periodic refresh to aid in bandwidth reduction. Images are also foveated to concentrate image detail in a steerable region. The system supports dynamic video quality adjustments between frame rate, image detail, and foveation rate. A typical configuration for the system used during driving has a frame rate of ~ 4 Hz, a compression per frame of ~ 125:1, and a resulting latency of < 1s.
Electrical and Computer Engineering