An Integrated Frequency Lowering Algorithm for Sensorineural Hearing Impairment

Abstract

An integrated frequency lowering algorithm is proposed to increase the audibility of high frequency signal and alleviate the spectral masking associated with sensorineural hearing loss, thus increase the intelligibility of the speech. Firstly, the input signal is transformed into frequency domain by FFT algorithm. Secondly, the energy of the low frequency band and high frequency band is calculated to determine whether frequency shifting is required to increase the audibility of consonants. Thirdly, the spectral samples in each bark-scale channel are compressed towards the band center by a constant factor to reduce the effect of spectral masking. Finally, frequency envelope shaping is utilized to increase the audibility of the whole frequency band. Five subjects with moderate sensorineural hearing loss participate the test. Experimental results demonstrate that the proposed algorithm out perform the conventional frequency lowering methods.