Technology Research And Realization In Sound Localization Based On Cortex-A8 Embedded System

With the rapid development of multimedia technology, Speech signal processing technology in the field of receiving and processing information has drawn more and more attention, applications of Speech recognition, speech enhancement, and the sound localization is burgeoning. And sound localization technology is the precondition and foundation of speech enhancement and speech recognition technology. Sound localization technology based on microphone array has become a hot research topic, and its broad application prospect has been widely concerned. Sound localization technology based on microphone array is mainly divided into the following types: Sound localization based on high resolution spectrum estimation, Sound localization based on controllable beamforming, Sound localization based on time delay estimation. Of these three algorithms, sound localization based on time delay estimation algorithm has low computing complexity and strong practicability, and it’s the first choice for real-time sound localization application. Because of this, this paper carried out the research of real-time sound localization based on time delay estimation algorithm.This paper mainly carried out the theoretical research, set the hardware and software platform of the sound location system, and verified the validity of the system.(1) In this paper, the second chapter carries out the study of time delay estimation algorithm. On the basis of the analysis of comparing all kinds of microphones formations, this paper choose four-element cross array as the formation of microphone arrays, and deduced the formula of sound localization algorithm based on the four-element cross array. On this basis, several kinds of sound localization algorithm based on time delay estimation is studied. In view of the generalized cross-correlation algorithm has poor robustness in low SNR, big reverberation environment, a multi channel weighted combination algorithm is proposed, which first decomposes the signal, and then calculate the cross-correlation values of each channel, at last the channels are weighted and joint to calculate the time delay. Simulation results show that multi channel weighted combination algorithm has stronger robustness than generalized cross-correlation PHAT and SCOT weighted algorithm.(2) Based on the theoretical study. The sound localization system based on Cortex-A8 architecture embedded platform is designed, which includes hardware choosing and debugging and algorithm transplantation. Firstly, in terms of hardware design, S5PV210 is chosen as the core processor, WM8960 is chosen as audio codec chip, and the peripheral circuit is built up. Secondly, in terms of software development, the software system is set up, the WM8960 audio driver is transplanted, and localization algorithms are written, tested, and transplanted. Finally, the sound localization system based on Cortex-A8 architecture embedded platform is completed.(3) In order to test the feasibility of the system, a series of experiments under outdoor environment is carried out. The results show that the scheme of this system is reasonable and effective, and can locate the sound source well. In addition, in view of the insufficiency of this system in real environment, this paper also gives some schemes to improve the performance, which provides some ideas to develop a more effective sound localization system.