Phase-sensitive speech enhancement for cochlear implant processing

In this paper, we present a new approach to enhance noisy speech based on an environmental model incorporating the phase between noise and clean speech (often called phase-sensitive model) in log power spectral domain. Some previous phase-sensitive methods normally assume the phase factor to be a random variable or set it heuristically. In this work, we assume phase to be an unknown parameter that can be estimated deterministically from data and present an algorithm for its estimation. Words-in-sentences recognition by twelve cochlear implant subjects was tested under six different noisy listening conditions with and without the speech enhancement algorithm. Experimental results show that the proposed phase-sensitive approach significantly improves the recognition of noisy speech and significantly outperforms other conventional phase insensitive methods in all listening conditions.