Correction Microphone Array Reverberation Environment, Research, And To The Reverberation Method

Microphone arrays are different from traditional single microphone systems. The received signals from microphone arrays contain space information of sound sources. By processed, they can realize sound source localization, restraint of directional interference, speech enhancement, and speech separation. Compared with conventional single microphone systems, microphone arrays extend the performances and functionalities of sound processing. Thus, they have comprehensive application fields and good market prospective. For example, they can apply to hearing aid, vehicle telephone, and video conference. The current research directions of microphone arrays are speech localization and speech enhancement. The related algorithms are various. In practice, however, performances of these algorithms are dissatisfied. The products of microphone arrays systems are less and their performances degrade heavily compared with ideal values. The contrasts between the advantages in the theory and the performances in practical applications are the current main problems in microphone arrays. They are also the research hotspots.In this paper, the speech source localization and enhancement algorithms based on microphone arrays are firstly analyzed and compared. The MUSIC and MVDR algorithms are focused. The main reasons that cause the dissatisfaction of practical application are the ideal array model which is adopted by these algorithms does not take the actual factors such as array gain and phase errors, reverberation into account. Then, the influences of array model errors to these two classical algorithms are analyzed and related simulation results are given. Then, an active-calibration approach is proposed. Based on this approach, this paper investigates the influences of reverberation to speech processing algorithms and calibration approach. An active-calibration approach under reverberation is proposed. Finally, the general processing platform of microphone array is illustrated.The main work of this paper is as follow.(1) The acoustics foundation of microphone arrays is first illustrated. The influences of microphone arrays of model errors to MUSIC algorithm and MVDR algorithm are analyzed and the related simulation results are given.(2) The model errors of microphone array are analyzed. An active-calibration approach is proposed. This approach requires the exact locations of test sound sources. It can calibrate the gain and phase errors. The simulation results verify the effectiveness of this approach.(3) The influences of reverberation to microphone arrays and calibration approach are analyzed. An active-calibration approach under reverberation is proposed. The problem of degradation of gain error calibration is solved preliminarily.