基于离散泊松方程解的相位展开方法

Phase Unwrapping Method Based on the Solution of Discrete Poisson Equation

提出了基于离散泊松方程解的相位展开方法 ,针对被测件表面疵病 (阴影、断裂、孔洞、噪声等 )奇异点所产生的相位跳变和截断 ,建立了相位展开算法模型 ;引入离散余弦变换求解具有诺埃曼边界条件的离散泊松方程 ,得到最小二乘意义下的展开相位解。经实验证明 ,该方法能够消除干涉图奇异点相位跳变 ,消除传统相位展开法所产生的“跳序”和“拉线”现象 。

A phase unwrapping algorithm based on the solution of discrete Poisson equation is presented to retrieve the true phase of the object from wrapped phase. Algorithm model is constructed aiming at phase discontinuous and jumping caused by oddity points in interference pattern. Discrete cosine transform (DCT) is introduced to solve discrete Poisson equation which has Neumann boundary condition. Phase unwrapping results are obtained under least-squares method meaning. In comparison with the traditional algorithm, this method can effectively remove the discontinuous influence of shadow, blind spots, holes and noises, remove order jumping and wire drawing and resume true phase at the same time. Preferable experimental results are obtained in phase-shifting interference measurement.