数字散斑联合变换相关法测量微小位移的研究

Study on small displacement measurement using digital speckle joint fourier transform correlation

提出一种利用联合变换相关法对位移前后的散斑图像实现数字相关运算,通过相关峰的距离与散斑图所携带的位移信息之间的关系,测量物体的面内位移量。通过对全场的位移计算,得出对散斑图像先做限幅预处理后,再进行边缘提取,有效减弱了影响相关峰的不利因素,提高了相关点的精确性。对同一组散斑图进行匹配滤波相关运算和联合变换相关运算,把得到的全场位移矢量图进行比较,得出两者测量的结果是一致的。

A method for the extraction of speckle displacement is presented. It transits digital speckle joint Fourier transform correlation （JTC） between the sub- specklegrams from different specklegrams to get the speckle displacement. For more accurate measurements, the experiment using clipped and distilled edge to digital speckle, The result proves this method can obtain two narrower cross - correlation peak and increase accuracy of measuring the peaks position, Comparisons of the result with Vander Lugt correlation （ VLC）, The full - court displacement vectorgraphs of JTC and VLC are accordant.