A Survey of Vision Aids for the Blind

The development of effective user interfaces, appropriate sensors, and information processing techniques make it possible to enable the blind to achieve additional perception of the environment. Since the beginning of the 1970´s, the research of vision aids for the visually impaired people has been broadly extended. After introducing the traditional methods for guiding blind, two typical modes of mobility aid are presented in this paper. One called as ETA (short for electronic travel aids), bases on the other natural senses of the blind, such as hearing, touch, smell, feeling and etc, focusing on Meijer´s voice system which is based on the blind´s sensitive auditory senses and ENVS which is by means of haptic feedback. The other technique is artificial vision, using surgical methods of implanting visual prosthesis in the blind´s healthy retina, cortex, or optic nerve. The prosthesis generates electrical impulse and evokes the perception of points of light in the patients´ visual cortex. The first type is non-wounded for the blind while the second type is wounded for the blind. Besides these, comparisons between the above two techniques and the related researches have also been indicated in this paper