It is the goal of this proposed research effort to evaluate an electronic vision substitution system as a blink mobility guidance device. We have developed a lightweight portable seeing aid for this application utilizing a miniature TV camera as a substitute visual input. We will also complete development of an ultrasonic camera to indicate the direction and distance of obstacles, thus simplifying the blind user's task. A point-for-point array of tactile stimulators displays a wide angle view of the forward sector of his environment onto the abdomen of the wearer in the form of corresponding patterns of electrical or mechanical vibration. In evaluating the sonic/optical mobility aid, spatial concepts will be taught to each individual during ten one-hour orientation sessions. Subjects will learn to discriminate movement, size, angular alignment, distance and crude forms. Next, another ten individual one-hour sessions will be devoted to indoor mobility training; first, without, and then, with the long cane. Tasks will consist of detecting and avoiding poles, overhangs and real furniture, as well as walking prescribed paths through a maze of such objects. Outdoor mobility training will occupy thirty hours and start on a large open lawn, the task gradually increasing in complexity. Exercises will consist of shadow interpretation, path navigation, shorelining a fence or building, detecting sidewalk curbs (with contrast enhancement), learning the effects of angle of view on shape distortion and recognition, avoiding natural obstacles, navigating sidewalks, dealing with pedestrian traffic situations and street crossings. The formal performance evaluation procedure is expected to take ten hours and will measure objective travel characteristics, such as time to complete the task, number of collisions, number of pedestrians touched with cane or body, number of objects identified, number of crosswalk lines violated, number of clear paths and openings detected without body contact, how far ahead curbs are detected and the smoothness of the travel path (in RMS deviation). Questionnaires will also be completed by each subject and the mobility instructor in order to collect further information difficult to assess objectively. Data for technical evaluation of the equipment will be collected at intervals throughout the entire training and evaluation procedures.