激光波数扫描干涉相位解卷绕算法研究

Phase Unwrapping Algorithm for Laser Wavenumber Scanning Interferometry

激光波数扫描干涉技术作为一种具有微米级检测分辨率和微应变级测量精度的新型干涉图像测量方法,能够透视测量复合材料内部的微观结构信息,实现材料的高精度无损透视成像检测。作为干涉图像数据处理至关重要的环节,相位解卷绕技术能将干涉图像信息从卷绕相位展开为解卷绕相位,还原干涉图像的真实信息。在传统相位解卷绕算法中,为了避免在噪声区域展开相位时相位展开错误进而导致误差的大面积传递,往往在存在噪声的区域停止相位展开,使得解卷绕后的数据存在缺陷及视场较小的问题,甚至可能无法正常解卷绕。针对以上传统算法的问题和研究了Goldstein枝切法在相位解卷绕中的应用。通过对噪声区域进行残差点判断设置枝切线,绕过枝切线进行相位展开,在所有正常点展开后结合枝切线周边的相位信息对枝切线上相位点完成最后的解卷绕,从而实现相位更有效地展开,减少相位展开后的数据缺陷,增大展开视场,精度更高。

As a crucial part of interferometric image data processing,phase unwrapping technology can unwrap the interferometric image information from the wrapping phase to the unwrapping phase,and restore the true information of the interferometric image.In the traditional phase unwrapping algorithm,in order to avoid the error transmission in a large area caused by the phase unwrapping error in the noise area,the phase unwrapping is often stopped in the noise area,which makes the unwrapped data have defects and a small field of view,and even may not be able to unwrap normally.In view of the above problems of the traditional algorithm,this paper introduces the application of Goldstein branch-cut method in phase unwrapping.The branch-cut line is set by judging the residual point in the noise area,the phase unwrapping is carried out by bypassing the branch-cut line,and after all normal points are unwrapped,the final unwinding is completed for the phase points on the branch-cut lines in combination with the phase information on the periphery of the brachy-cut lines,so that more effective phase unwrapping is achieved,data defects after phase unwrapping are reduced,an unwrapped field of view is increased,and the accuracy is higher.