Lexiphone : an experimental reading machine for the blind

An experimental reading machine for the blind has been built to test a proposed multidimensional audible code. This device, patterned after the popular Optophone reader, can generate either the multidimensional code or a simulated version of the Optophone code. The results of tests carried out with two blind subjects show that multidimensionally-encoded letters and words can be learned and "read" with reasonable accuracy, even when entirely different dimensions of the code are utilized. A comparative evaluation of the multidimensional and Optophone codes, based on the performance of 52 sighted persons, suggests that the multidimensional code provides a better basis for letter discrimination. A detailed study of the discrete print signals produced by this machine is presented. The results of this study suggest that this particular print scanning system does not lend itself to automatic letter recognition, but that, with some pre-processing of the print information, some optimization of the audible code can be achieved. It is also demonstrated that the information produced by this machine is highly redundant, and that the discrete nature of the print translation process may psychologically limit the maximum reading speed, regardless of the audible code employed.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat