A stereo auditory image-perception aid for the blind /

This thesis presents the research to develop a technical aid for the blind to perceive images such as a face or a scenery. The images scanned and explored interactively by touch through a probe mounted on the index finger of each hand. The pixel intensities of the image are displayed to the user as stereo auditory signals.For the study, the aid was implemented partly by using a personal computer, a computer graphics tablet, a digital-signal-processing board, and audio equipment. In addition, a Time-Multiplexer circuit was built to support inputs from two finger-probes which are made by using two styluses of the graphics tablet. The system softwares were programmed to present the images as stereo auditory display. The aid was evaluated on six blind-from-birth subjects and ten blindfolded sighted subjects to determine how fast and accurately they could perceive different multi-gray level images, and how their performance changed with increased experience. The results showed that, with increased experience, the same image presented in the second trial can be perceived in a shorter time than in the first trial. The subjects perceived the binary and the multi-gray level shapes within 2 minutes on average