Psychophysically Motivated Compression of Haptic Data

One of the key challenges in telepresence and teleaction systems is the fact that a global control loop is closed over a communication network. The transmission delay of haptic information is extremely critical. Therefore, new data samples from the haptic sensors are typically forwarded immediately to the receiver which leads to high packet generation rates and high network load especially if the Internet is used as the communication infrastructure. We present multiple approaches to reduce the amount of data communicated in a telepresence and teleaction system. Our new transmission strategies lead to reduced demand on the communication system and therefore more stable communication. The methods presented in this paper range from purely statistical exploitation of haptic data signals to psychophysically motivated compression using a passive deadband transmission approach. The latter only delivers data packets over the network when the sampled sensor data changes by an amount which is just above the human perception threshold. Our psychophysics based approach leads to a considerable reduction (up to 90%) of packet rate and data rate without sacrificing fidelity and immersiveness of the system and has been tested in 1-DoFand Multi-DoF-