Sound classification for hearing aids using time-frequency images

This paper presents a sound classification method for hearing aids based on time-frequency image processing. As an application of hearing aids in mind, four classes of ”Speech”, ”Speech in noise”, ”Noise” and ”Classical music” are prepared in order to classify the input signal of a hearing aid into useful classes. Although there are several possible ways to figure out which class the current input signal belongs to, an approach from image processing is utilised to find out several appropriate features because 2D image (time-frequency image) can contain multifaceted information compared to 1D information (waveform or frequency response of sound), and can be regarded as comprehensive data. It is found that eleven features are required to meet a certain quality of sound classification according to our investigation.