铁磁性材料脉冲涡流检测信号的消噪方法

摘要

为了能够有效地滤除铁磁性材料脉冲涡流检测信号中的噪声成分,提出基于小波分析和卡尔曼滤波器联合降噪的方法.阐述小波阈值降噪的基本原理,通过信号降噪试验优化小波降噪阈值参数,实现小波阈值最优降噪.针对小波降噪后的信号仍然存在少量非平稳噪声的问题,提出卡尔曼滤波器降噪方法,信号降噪试验结果表明：卡尔曼滤波器有效滤除了非平稳噪声,信号的信噪比达到34．9767 dB,均方根误差减小到0．049395.%Aiming at effectively filtering the noise components of pulsed eddy current testing signal in ferromagnetic materials,the method of wavelet analysis and Kalman filter denoising is proposed.The basic principle of wavelet threshold denoising is expounded and the threshold parameters of wavelet denoising are optimized through the signal denoising experiment.So the optimal wavelet threshold denoising is implemented.Because there exists still a small amount of non-stationary noise signal after wavelet denoising,the method of Kalman filter denoising is proposed.The signal denoising experimental results show that Kalman filter can effectively filter the noise components,increase the signal to noise ratio (SNR )to about 34.976 7 dB and reduce the root mean square error (R MSE )to about 0.0493 95.