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。

The properties of the output signal of heterodyne laser Doppler vibrometer (HLDV) under random noise disturbance are studied by means of wavelet transform. Considering the principle of HLDV and the influence of white noise in this system, the modulus maximum and the coefficient correlation algorithms are analyzed and improved. Also, based on the theory of the threshold enhancement, a new threshold function is proposed and used to analyze the effects of multi-scale method on the reconstruction of the oriental signal and improvement of signal-to-noise ratio (SNR). The results show that the improved modulus maximum, coefficient correlation and threshold enhancement algorithms present much more excellent performances in extracting the vibration parameters of the micro-vibration targets.