In this project we have created a DIGITAL HEARING AID using MATLAB software and Graphical User Interface. Aconfigurable digital hearing aids include a combination of frequency dependent amplification of speech and noise reduction filter for background noise reduction which will provide more flexibility to hearing impaired people along with improvement of quality of the speech signal.
The MATLAB implementation of the Digital Hearing Aid System is shown by the block diagram. The input signal by the user was recorded in a noisy environment. The input recorded signal will pass through several filters i.e. noise reduction by spectral subtraction filter, frequency adjustment filter and amplitude adjustment filter before constructing an output speech signal which is audible to the people with hearing loss.
The performance of the proposed approach has been evaluated through the simulations in MATLABevaluated through the simulations in MATLAB. The input speech signal is converted to digital signal, then processed by Matlab coding to denoise the signal, generate frequency shaping function to shape frequencies and by amplitude limiting generate the adjusted or modified signal which is audible to the patient. In this paper, two different degrees of hearing losses of different patients have been taken as objective to be modified.
After noise reduction of the original signal amplification of the recovered signal is done according to the level of hearing loss which is given as input by the user as shown.
It was observed from the above investigation, that,the gain on specific frequencies has been enhanced by adding frequency transfer/shaping function with the input discrete signal. The frequency shaping function has been designed according to the patient's requirement/hearing loss.