Ultrasonic eyeglasses for the blind

There is an obvious need for blind persons to perceive their environment in the greatest detail possible. The bat has demonstrated the effective use of ultrasonic waves for its own purpose of perceiving its environment. Man now has his own air‐sonar technology, in the form of eyeglasses mounted on the head, so as to perceive his environment. It may well be the best that can be achieved for helping blind persons by using their auditory channels to the cortex for spatial imaging and cognition of object space. This address describes the octave band CTFM air sonar with auditory coupling to the brain. The method of testing its physical performance is related to the human auditory perception of object space experienced by users. FFT analysis shows a distal resolution of approximately two wavelengths. However, behavioral analysis of a user performance suggests a greater neural ‘‘resolution’’ of object space is available. This resolution is demonstrated by the natural real‐time perception of object‐shape characteristics. The ‘‘infinity’’ of sonar object ‘‘signatures’’ are seemingly absorbed by the listener’s neural system and eventually learned. The small nuances in the real‐time change in sound structure as an object pose is altered are invariant. This requires an enormous memory.