A. C. Surendran
J. L. Flanagan
Ctr. for Comput. Aids for Indust. Productivity, P.O. Box 1390, Piscataway, NJ 08855-1390
The impulse response of a reverberant environment, in general, is a nonminimum phase and cannot be inverted. But an exact inverse of the environment can be obtained by modeling the room as a multiple input--output (MINT) system [M. Miyoshi and Y. Kaneda ICASSP (1986)]. In this report, this model is applied to a microphone array and is used as a front-end processor for a speaker verification system. The G matrix is inverted using row action projection (RAP), an iterative approach to solving a system of linear equations. Starting from an initial guess, the solution is repeatedly projected onto each hyperplane of the equation system until it converges. The method is stable, robust to noise, and converges to the pseudo-inverse solution. In computer-simulated experiments, the signal-to-reverberant-noise ratio is found to improve with the number of microphones in the array. A speaker verification system using the array is evaluated at various signal-to-competing-noise ratios (SCNR). Results suggest that verification performance can be substantially elevated in adverse acoustic environments.