小波变换在位相展开中的应用

Application of wavelet transformation in phase unwrapping

在结构照明型光学三维传感和干涉型计量技术中 ,都需要将计算出的截断位相恢复为物理参数对应的连续位相。位相展开的过程中 ,对于十分复杂的截断位相 ,如何有效地标记出极点和截断线是至关重要的。本文提出利用小波变换寻找截断线的方法。利用小波变换系数的模极大值与局部奇异性的关系 ,通过检测小波变换系数模极大值的位置来标记截断线的基本走向 ,进而采用图像处理中的二值数学形态学处理方法形成完整的截断线 ,构成指导位相展开的控制模板。新算法有效地标记了极点和截断线 ,将位相展开的错误限制在局部范围。

In optical 3D sensing based on structured light projection and interferometry,it is essential to retrieve the natural phase corresponding physical parameters from the unwrapped phase calculated.In phase unwrapping,how to mark the poles and blocklines is crucial to a very complex wrapped phase.This paper gives a method applying wavelet transformation to get the blocklines.Using the relationship between the local modulus maxima of wavelet coefficients and the local singularity,to trace the blocking lines according to the position of modulus maxima.Then using the method of binary image analysis and mathematical morphology to get the complete blocking lines,and to construct the binary control mask to supervise phase unwrapping.The new method is to mark the poles and blocklines successfully,and remain the errors of phase unwrapping within the local confines.This paper gives the analysis of the method in detail and the results of the computer simulated experiment.