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An overview of both early and recent developments in artificial aids for blind orientation and mobility is presented. Most aids developed previously fall into the category of "mobility aids" intended to sense obstacles in or near the traveler's immediate path. The more global problem of absolute orientation and navigation has not been well addressed by researchers in electronic aids, but this situation is now changing. A new system for aiding blind orientation, described here, is now advancing beyond the experimental stage.
John A. Brabyn (Thu,) studied this question.