基于互相关与混沌检测相结合的光声信号检测方法

Photoacoustic signal measuring based on cross-correlation analysis and chaotic detection

采用光声光谱方法检测变压器油中溶解气体的体积分数时,由于变压器运行现场的干扰以及检测过程中存在的噪声使得微弱光声信号湮没在强噪声中而无法辨识。在分别对互相关运算和混沌检测进行分析说明的基础上将这2种方法结合起来作为微弱光声信号检测的理论依据。集成LabVIEW和Matlab软件构建了虚拟信号检测系统,编程实现了由李雅普诺夫特性指数谱来判定混沌系统运动状态的功能。实验结果表明该方法对被强噪声覆盖的微弱光声信号非常敏感,具有较高检测精度。

When photoacoustic spectrum is used to measure the concentration of dissolved gases in transformer oil,the weak photoacoustic signals can not be differentiated from the strong field noises and test interferences. Cross- correlation operation and chaotic detection are introduced,based on which a method integrating these two theories to detect weak photoacoustic signals is proposed. A virtual signal detection system is built with LabVIEW and Matlab,and the Lyapunov characteristic exponent chart is programmed to realize the function of chaotic state determination. Experimental results show that this method is very sensitive to the weak photoacoustic signals under strong noise and has higher detection precision.