Speech processing for intelligibility improvement

Literature on speech processing to enhance intelligibility in poor listening conditions was reviewed. As the perception of consonants is essential for intelligibility, relevant acoustic features were surveyed. Data from consonant spectra measurements and from listening experiments in which certain features of the consonants were varied were collected. The effects of disturbances, such as background noise and resonances, on intelligibility were investigated. Processing methods carried out on speech to improve its quality are summarized.