摘要
针对采用传统频域数字散斑相关法测量面内微位移受到噪声的影响严重、测量精度低等问题,提出了一种新的频域数字高阶涡旋散斑相关法。首先,通过高阶涡旋散斑图生成实验,发现了高阶涡旋散斑图具有抗噪声干扰能力强、在相关器输出面上能得到面积小且亮度高的相关点,于是将待测物体的高阶涡旋散斑图作为测量对象;然后通过理论计算推导,应用减运算合成位移前后的高阶涡旋图,可以在相关器输出面上同时显示位移前后的两个相关点,突破了传统方法只能显示位移后一个相关点的现状,并且有效抵消了背景噪声;最后设计了一种新型的滤波器对合成图进行匹配滤波,可以生成峰值锐利的相关光斑图。实验结果验证了,该方法使得测量精度和抗噪声干扰能力得到极大提高,在不同噪声干扰下相对误差仍能保持小于2%。
For the problem of being susceptible to the influence of noise, low accuracy in micro in-plane displacement measurement using traditional digital speckle correlation in frequency domain, digital higher-order vortex speckle correlation method in frequency domain is proposed. First, it is found that higher-order vortex speckle pattern has an ability to resist noise and the output surface of correlator can get smaller and brighter correlation points according to the experiment of generating higher-order vortex speckle pattern, then using higher-order speckle pattern as measured object. Second, theoretical calculations are deduced, and then new patterns before and after displacement of the higher-order vortex speckle are synthesized using subtract operations. The two correlation points can be gotten on the output of correlator, which changes the current status that only has one correlation point using traditional method, effectively counteracting background noise. Finally, we design a new filter to generate the relevant spot diagram, whose correlation spot map peaks become sharp. Experiment results show that the algorithm has made great advance in reducing noise and improving accuracy, which can maintain relative error less than 2% under different noise
出处
《光电工程》
CAS
CSCD
北大核心
2015年第11期54-61,68,共9页
Opto-Electronic Engineering
基金
总装备部预研基金
关键词
减运算
频域
数字散斑相关法
高阶涡旋
匹配滤波器
subtract operations
frequency domain
digital speckle correlation method (DSCM)
higher-order optical vortex
matching filter