Yael Zilbershtain-Kra, Ehud Ahissar* and Amos Arieli*
Weizmann Institute of science
Sensory substitution systems deliver environmental information we normally receive through one sense (usually vision) through another sense. Although such systems exist for more than 50 years, none of them has been adapted so far by the blind community for practical everyday use. Assuming that the primary barrier with these devices’ was incompatibility with natural perceptual strategies we developed a biomimetic substitution system based on active sensing that allows the perception of remote objects via the fingers. We tested this device with blindfolded sighted and with blind participants who were asked to recognize 2D images and physical object presented at a distance of ~1 meter. We measured their accuracy, recognition time and hand motion. Results showed a steep learning curve. Participants reached success rates of 86.6% in the 2D task and 95% in the 3D task in less than 30 s per trial. Fast and accurate perception was found to maintain after ~2 years. During training participants attained externalization of the sensed data, and developed an ability to identify local features (e.g., curvatures, vertex and corners). The participants developed scanning trajectories that resembled those exhibited during vision in sighted subjects, with the most salient common pattern being a focal scanning of an object-specific informative region. Over all our results suggest two major principles that improve significantly the perception via Sensory substitution.
The first is employing natural-like active sensing strategy. The second is having motion and sensation on the same body organ. Moreover, we show that these improvements depend critically on a natural-like strategy that the participants developed. These principles are especially relevant for developing sensory augmentation devices.