Video Resolution, Frame Rate and Grayscale Tradeoffs under Limited Bandwidth for Undersea Teleoperation

摘要

The high costs associated with a diver working at depths approaching 100m make the use of remotely controlled visual inspection and manipulation look very attractive. When the undersea teleoperator is untethered, and acoustic communication is used, there are severe restrictions on the bandwidth of the image transmission channel. Sine the product of the Frame Rate (F), Resolution (R) and Grayscale (G) is directly proportional to the transmission band rate, for a fixed channel capacity there are tradeoffs between F, R and G in the actual sampling of the picture. A manipulator was used in the MASTER/SLAVE mode to study these tradeoffs. A mathematical model for image reconstruction was used to design a system which would allow the operator to set independently the F, R and G of the picture. This design was implemented using a commercially available charge coupled camera with its accompanying digitizer, and an electronic unit was constructed to interface with the digitizer and camera. It was the conclusion of the author that a well trained operator could perform tasks familiar to him/her with a considerably degraded picture. Furthermore, for a given task and transmission rate, some FRG combinations are more effective than others. For the particular tasks experimented with, 50,000 bits/sec was found to be a satisfactory transmission rate. (Author)