FFT-based fast conjugate gradient method for real-time dereverberation system

When speech at a location away from a microphone is received, the received speech is degraded by reverberation in a room. To deal with this problem, a semiblind dereverberation method has been proposed in which no prior measurement of the room impulse response is used. However, the fast computation was required because an enormous amount of computation is needed for inverse filter calculation. In this paper, an acceleration method for the inverse filter calculation in the semiblind dereverberation method is proposed. For speed enhancement, the similarity of the correlation matrix to the convolution matrix is considered. By using fast convolution by the FFT in the conjugate gradient method, a dramatic increase in computation speed is achieved. A real-time dereverberation system was constructed on a personal computer by installing the proposed method and was tested in an actual environment. It was confirmed that the proposed method can achieve high-speed operation without degradation of dereverberation performance. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(7): 25–36, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20292