The Research And Implementation Of Microphone Array Speech Enhancement Technique

To reduce the noise interference involved in the received speech signals as efficiently as possible, speech enhancement is put forward and well developed. Different noise environment should adopt corresponding enhancement method .There exist not only noise but also echo and reverberation in some occasions like car telephone and video conference .So multichannel speech enhancement method has been put forward to solve this problem in which single microphone can't achieve ideal result .Speech enhancement algorithms based on microphone array develop from antenna array,but also take advantage of some speech enhancement algorithms based on single channel .Microphone array can ruduce the noise more effectively than the single microphone because it can provide time,frequcecy but also space information. Voice activity detection (VAD) is a key part in most kinds of speech enhancement methods with microphone array and their performance directly affects the results of speech enhancement.In this thesis, we present two VAD algorithms which are VAD based on Mel scale short-time average energy difference and VAD based on subband short-time average energy and average zero-crossing rate.The algorithms performance have been showed according to the simulation experiment on matlab.With the background knowledge on the speech enhancement which includes room reverberation, acoustic field model, time delay estimation and array model, this thesis studied the delay-and-sum beamforming,generalized sidelobes canceller and postfiltering method. The performance of different algorithms are analyzed in details and the results of simulation tests are given.In this paper, the study of basic principles on speech enhancement with microphones array provides a positive effect on the following further research and comparison among kinds of speech enhancement and TDE methods. In addition, a software application scheme for the system of speech enhancement with microphones array using GSC algorithm based on ADSP-BF533 is provided, developed and simulated.