An Investigation of Monoscopic and Stereoscopic Video for Teleoperation


David Drascic

Department of Industrial Engineering
University of Toronto
4 Taddle Creek Road
Toronto, Ontario
Canada M5S 1A4

drascic@ie.utoronto.ca


A Thesis submitted in conformity with the requirements for the degree of Master of Applied Science in the University of Toronto.
(c) Copyright by David Drascic 1991.

Some of this material is of a sensitive nature and has been deleted at the request of the sponsors of my work. I have marked the deleted sections.


Abstract

There are many tasks hazardous to human life which can be accomplished remotely through telerobotic manipulation. Robotic technology has advanced to the stage where teleoperated manipulators are versatile and effective enough to be used successfully in a wide variety of circumstances. As telerobotic systems become more sophisticated, it is important to ensure that the human-machine interface is adequate for the task. One very important type of feedback information that is missing from standard telerobotic control stations is the immediate and compelling binocular coding of depth, which is thwarted through the use of a standard monoscopic ( "2D") video system, making the operator dependent on other less salient visual cues. This is unfortunate, since most telemanipulation tasks require operators to have a good sense of the relative locations of objects in the remote world.

To that end, a practical Stereoscopic Video (SV) system was developed that is compatible with standard video display and recording equipment. Two experiments were conducted to examine the potential benefits of SV for teleoperation, with particular emphasis on the effect of experience.

The first experiment examined the issue of whether it was easier to learn how to interpret a SV display than a standard monoscopic video (MV) display. Using a task that had very little demand for binocular depth cues (i.e. was SV-independent), it was found that there was a benefit in performance due to SV that diminished as the operators learned how to use the monocular cues of the MV display. Furthermore, the first experiment provided evidence to suggest that SV can be used effectively with little or no training, while MV requires a period of adjustment and learning.

The first experiment also revealed an interesting transient effect that changing from one video condition to another can have on performance. Those who change from an SV to a MV display show a temporary but dramatic drop in performance, while those who change from a MV to an SV display show a large improvement in performance. The results of the experiment and the literature suggest that the differing appearances of "reality" of the two displays may affect the confidence of the operators in their abilities to perform the task, and so therefore affect their performance.

The second experiment examined the second issue, that of how the transience of the benefits of SV are a function of the difficulty of the task and the dependence on binocular depth cues. It showed that the benefits of SV, even after a great deal of practice, will still be apparent for difficult tasks, long after the benefits have faded for easier tasks.


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