Compression of obstacle avoidance sonar data for low bit rate image transfer

Modern obstacle avoidance sonars utilize wide bandwidth pulses, fast sampling rates, and high-resolution sampling to form beams with wide dynamic range and precise range resolution. As a result, many obstacle avoidance sonars generate image data at 10 Mbits per second or faster. Obstacle avoidance sonar image data must often be transferred from a remotely operated vehicle to its control station via an RF link or an acoustic link, or sonar image data must be transferred from the sonar processor to an autonomous vehicle controller via a low-speed serial link. In all these cases, the data must be compressed. We have developed lossy data compression techniques which provide compression factors of 100 or more with little degradation in system performance. We describe a compression technique optimized for autonomous vehicles and three techniques for image data compression for remotely operated vehicles. We discuss why these compression techniques are particularly well suited for obstacle avoidance sonar image data