Research On Several De-noising Methods In Laser Sound Detection

Sound detection is an important way to keep abreast of the latest information and keep abreast of trends.It is a key technology in all countries of the world.Laser sound detection technology uses laser as the sound detection carrier,which can detect the sound signal in the venue without the presence of the scene,and it has better concealment and anti-interference.Therefore,it is of great significance to research laser sound detection technology and realize laser sound detection.This paper mainly studies the de-noising method of laser detection sound signal.Firstly,the basic principle of laser sound detection is analyzed from the perspective of the incidence,reflection and refraction of light and the energy density of light.Design and build a laser sound detection system in a laboratory environment,based on the detection process and detection environment of this system,a comprehensive analysis of the source of the noise was performed,and the noise in the detection signal was classified from the interference pattern of the signal.By analyzing the four-quadrant detector of the laser sound detection receiver and its detection principle,the background light not only affects the signal-to-noise ratio of the detection signal,but also causes the error of the spot position solution.The background light interference is suppressed by optimizing the laser detection systemFor different kinds of noise sound signals,spectral subtraction and LMS adaptive filtering in the speech signal de-noising method are used for de-noising,and a better de-noising method for different noise signals is obtained.According to the short-time non-stationary characteristics of sound signals,the classical wavelet threshold de-noising method in wavelet de-noising is introduced.The selection methods of important parameters in the wavelet threshold de-noising method are introduced.The commonly used threshold functions are introduced in detail and an improved threshold function is proposed in view of their shortcomings.Finally,the sound signal obtained by laser detection is de-noised using different methods.Comparing the quality of the signal after de-noising by various methods,a better method for de-noising the laser sound signal is obtained.Through the above research,the optimized laser sound detection system achieves a suppression effect on background light interference.Basic spectral subtraction has relatively good de-noising effect on broadband noise,and improved spectral subtraction has relatively good de-noising effect on periodic noise.LMS adaptive filtering is better than spectral subtraction for all types of noise,and it has the best suppression effect on wideband noise.In the de-noising of laser sound signal detected by wavelet threshold de-noising method,different threshold functions are used to obtain different de-noising effects,and the improved de-noising effect is obtained by using the improved threshold function proposed in this paper.