基于改进型小波阈值的磁记忆信号去噪研究

磁记忆检测信号易被外界噪声污染,使缺陷信号的可检测性受到极大影响。为消除噪声信号的不利影响,通过优化传统算法进行了磁记忆信号的消噪。硬阈值去噪得到的估计小波系数值连续性差,并会引起重构信号的振荡;而软阈值去噪会与原来的小波系数存在恒定偏差。在软、硬阈值函数的基础上,提出了一种改进型阈值函数,该阈值函数在一定程度上克服了传统方法的不足之处。仿真试验结果表明了改进型阈值函数对去除磁记忆信号噪声的适用性。

Denoising Research on Magnetic Memory Signal Based on Improved Wavelet Threshold

The magnetic memory signal is easy to be disturbed by various sources of noises,which leads to the detectability of defect signals being greatly influenced.For eliminating the signal noise,the magnetic memory signal is denoised by optimizing the traditional algorithm.After hard threshold denoising,the continuity of the estimated wavelet coefficient will be poor,and the reconstructed signal may oscillate.However,there will be constant deviation between the original wavelet coefficient and the estimated wavelet coefficient.Based on soft and hard threshold function,an improved threshold function is put forward,which solves the problems existing in traditional method in a certain extent.The result of simulation experiments shows the applicability of improved threshold function in magnetic memory signal denoising.