Stereo vision in teleoperation: interactions between motion in depth and static depth

It is shown that the percept of motion in depth interacts with the percept of static depth, and this interaction may result in small, but highly statistically significant, static depth distortions. This interaction fades with time, but persists at least one second. Specifically, an object that moves toward or away from the stereo cameras, and then stops, is perceived as being located in a different depth plane than the same object when perceived without prior motion. Four trained human observers were tested with high-resolution, low-distortion stereo camera configurations. With a viewing distance of 1.3 m, motion-induced static depth distortions on the order of millimeters and/or fractions of millimeters were measured. All the motion-induced distortions were reduced with static depth viewing time. In addition, operator certainty for static depth discriminations increased with static depth viewing time. One may avoid adverse performance effects due to these distortions by training operators to make motions in depth slightly smaller than would seem necessary, and then to pause a few seconds between motions in depth and precision work