Binaural hearing assisting system with spatial selectivitybased on the frequency domain binaural model

摘要

A hearing aid system not only for hearing-impaired person but also elderperson, called a hearing assistant system, has been developed for a long time. The hearingaid system becomes smaller with a development of hardware day by day. However, almosthearing aid systems control only sound pressure level without selection of sound sources. Eventhough two hearing aids are attached to both ears, the almost systems do not take into accountof binaural information. Recently, frequency domain binaural model has been proposedby Nakashima et al. The model can enhance several sound sources located in three spatialdimensions with two sensors simultaneously. The segregated sound has binaural information.In addition, calculation cost of enhancement processing is very low. Since the system based onfrequency domain binaural model can reduce noise level of undesired sound sources, it is expectedto obtain comfortable hearing. This paper proposes to use a frequency domain binauralmodel as a front end of hearing aid system. A prototype of the proposed system is constructed.A microphone is attached to a cover of a loud speaker for each ear as active noise control headphonedoes. Performance with respect to directivity of the system in three spatial dimensionsis measured by both computer simulation and experiment. As a result, noise signals, whichcome from undesired directions, are suppressed over 7.5 dB in the experiment.