Indian Journal of Science and Technology

Abstract

Objectives: The performance of hearing aid largely depends on its ability to enhance the quality of speech. The objective of this paper is to find out the changes in time pattern of the speech signals which would help to resolve the issue of the temporal resolution. Methods/Statistical Analysis: Various Fourier transformation techniques are available for speech enhancement in hearing aid. This paper proposes Short Time Hartley transform (STHT) signal processing technique based phase vocoder for hearing impairment. Pitch shifting though time scaling is obtained by using phase vocoder. The proposed algorithm is implemented in MATLAB and verified with Vowel Consonant Vowel (VCV) data sets. Findings: In this paper, formants which are concentration of acoustic energy around a particular frequency are calculated for both STFT and STHT techniques and compared for performance evaluation using VCV data sets. The variation in pitch and power for different time scaling factors is observed which reflects the changes in time pattern of speech signals. The results obtained supports Short-Time Fourier transforms (STHT) signal processing technique to be effective for Phase vocoder performing time scaling and pitch shifting of audio as well as speech signals and can be a remedy for temporal resolution issue. Application/Improvements: As pitch shifting is observed towards both lower and higher frequency ranges, STHT can be a suitable processing technique, beneficial for hearing impaired people with sensorineural hearing loss.

Keywords: Hearing Impairment, and Sensorineural Hearing Loss, Phase Vocoder, Short Time Hartley Transform (STHT)