Signal Processing Techniques Used in Digital Hearing-Aid Devices: A Review
Manik Sadashiv Sonawane, Sangeeta R. Chougule · SSRN Electronic Journal · 2019
Hearing impairment is a commonly observed human health problem across the world. In “hearing loss”, hearing sensitivity is reduced. To treat hearing loss problem, hearing assistive devices are used. Hearing aids restore hearing ability for those having hearing problems. But with today’s most advanced technologies in hearing aids, patients still have some difficulty in understanding speech in crowded areas. Hearing aid has hearing loss match up and adjustment of the hearing aid characteristics according to an individual patient. Digital hearing-aid device amplifies sound selectively by use of digital filters and the processed signal is transferred to the ear. Hearing-aid designers are continuously trying to minimize background sounds and noise with these additional directional microphones, adaptable noise reduction filters and uses of binaural hearing aid technologies to improve localization. Lots of studies have been already done to design digital filters for selective amplification. Most of the available hearing-aid designs have digital filter bank and fixed sub-band structure. Previous research aims at creating band decomposition, and the research is focused on using less complex algorithms for accomplishment of the decomposition of signals. The paper reviews available designs and reconfigurable digital filter banks to achieve the best fitting to audiogram.