Sound And Light Integrated Monitoring System Based On The Embedded Platform

With the development of technology in video monitoring,and the increasing demand for intelligent monitoring,the traditional monitoring system has failed to meet the requirement on many situations.The sound and light integrated monitoring system based on the embedded platform is proposed in this thesis.The sound source localization technology is applied to the system.It is more intelligent compared with the traditional video monitoring system.Consequently,it has important practical value.The main contents are as follows.(1)The asynchronous acquisition method is proposed the sound source localization technology.By using the sampling characteristics of the asynchronous acquisition device,the realization cost of the sound source localization is reduced,and the acquisition channel is easy to expand.Then,two kinds of correction methods based on MVDR algorithm and TDOA algorithm are proposed to solve the problem of error caused by delay sampling between channels in the localization of sound source.(2)In the correction of MVDR algorithm,asynchronous acquisition system sound data waveform is compared with synchronous acquisition under the same conditions to find the delay points between the peaks.According to the number of delay points for translation and interpolation processing.The processed data is put into the algorithm to calculate the results.The experimental results shows that the proposed method can effectively improve the estimation error of azimuth of sound sources in a given sound field.(3)In the correction of TDOA algorithm,firstly,the GCC algorithm is used to acquire the relative delay between the acquisition channels through the acquired audio data.Secondly,the acquisition delay error is corrected by the software compensation method.Finally,the location of the sound source is estimated from the geometric relationship between the source and the element.The experimental results shows that the method can estimate the azimuth of the sound source more accurately.(4)A sound and light integrated acquisition platform based on embedded platform is designed to implement the acquisition of sound signal and video image respectively.The hardware system can be divided into a core-board and a base plate(5)though adopting module hiearchy.The software design with multithreading programming technique can achieve continuous signal collection and real-time display.