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基于小波变换对外差式激光多普勒振动测量系统(HLDV)输出信号进行了噪声抑制性能研究。从外差式激光多普勒测振系统的测量原理出发,结合系统回波信号的特点,考虑测振系统中白噪声的影响,分析并改进了模极大值法和系数相关法两种小波消噪处理算法,并基于以往的阈值去噪算法,提出了新的阈值函数,重点分析了多尺度细化分析对还原原始信号特征及改善信号信噪比(SNR)的影响。结果表明,针对微振动目标运动特征提取,改进后的三种方法在振动信号的特征提取及噪声消除方面具备优异性能。
Based on wavelet transform, the noise suppression performance of HLDV output signal was studied. Based on the measurement principle of heterodyne laser Doppler vibration measurement system, the influence of white noise in vibration measurement system is considered in combination with the characteristics of echo signals. Two kinds of wavelet, modulo maximum value method and coefficient correlation method, are analyzed and improved Based on the previous threshold denoising algorithm, a new threshold function is proposed, and the effect of multi-scale refinement analysis on restoring the original signal characteristics and improving signal-to-noise ratio (SNR) is analyzed emphatically. The results show that the improved three methods have good performance in feature extraction and noise elimination of micro-vibration target.