Yuchang Cao

Improving the performance of a small microphone array at low frequencies using critical band and LPC codebooks

This paper presents a novel method for improving the low frequency performance of a microphone array by use of a twin codebook consisting of critical band energy and LPC distribution of speech. A modified Wiener filter created using these codebooks eliminates residual noise at low frequencies, which may result from the limitation of the array size or the beamforming algorithm. The preliminary simulation tests have shown that the proposed system is effective, and may provide good performance for those microphone array systems which are installed on a computer in an office, or in a moving vehicle.

Speech separation by simulating the cocktail party effect with a neural network controlled Wiener filter

A novel speech separation structure which simulates the cocktail party effect using a modified iterative Wiener filter and a multi-layer perceptron neural network is presented. The neural network is used as a speaker recognition system to control the iterative Wiener filter. The neural network is a modified perceptron with a hidden layer using feature data extracted from LPC cepstral analysis. The proposed technique has been successfully used for speech separation when the interference is competing speech or broad band noise.

Post-microphone-array speech enhancement with adaptive filters for forensic application

A multi-microphone speech enhancement system including two stages of processing has been developed. In the first stage, the array is aimed at the desired signal source and the noise signal source(s) respectively by means of the Frost algorithm or DS beamforming. In the second stage, the difference between the SNRs of the array outputs are employed to improve the SNR of the desired signal further by an adaptive filter with MRSS (matrix ratio sub space) algorithm. This algorithm is based on the orthogonal and coincidental subspace eigen analysis. The mathematical derivation and the simulation results that illustrate the advantages of the system are presented.<<ETX>>