Omnidirectional Haptic Guidance for the Hearing Impaired to Track Sound Sources

We developed a hearing assistance system that enables hearing-impaired people to track the horizontal movement of a single sound source. The movement of the sound source is presented to the subject by vibrating vibrators on both shoulders according to the distance to and direction of the sound source, which are estimated from the acoustic signals detected by microphones attached to both ears. We presented the direction of and distance to the sound source to the subject by changing the ratio of the intensity of the two vibrators according to the direction and by increasing the intensity the closer the person got to the sound source. The subject could recognize the approaching sound source as a change in the vibration intensity by turning their face in the direction where the intensity of both vibrators was equal. The direction of the moving sound source can be tracked with an accuracy of less than 5° when an analog vibration pattern is added to indicate the direction of the sound source. By presenting the direction of the sound source with high accuracy, it is possible to show subjects the approach and departure of a sound source.