基于中心旋度分割的单频结构光相位展开算法

Single-Frequency Structured Light Phase Unwrapping Algorithm Based on Central Curl Splitting

在三维成像领域,对包裹相位进行精准解相是一个重要的研究问题。可以利用枝切法和最小二乘法等方法对单一频率的包裹相位图解相,由于噪声或阴影的影响,枝切法解相位容易产生“孤岛”效应,最小二乘法处理的结果可能会偏离相位真实值。针对以上不足,提出基于中心旋度分割的相位解包裹算法,计算包裹相位图中每个像素的中心旋度,分割出中心旋度为0的区域和不为0的区域,分别用洪水填充和二阶差分倒数排序对包裹相位解包裹,在区域边界处进行相位抬升处理,从而获取完整的绝对相位图。仿真结果表明,所提算法解包裹的性能明显优于枝切法和最小二乘法。实验结果表明,基于中心旋度分割的相位解包裹算法可以有效地实现对被测物体表面轮廓信息的三维成像,叶片表面三维测量误差小于等于0.08 mm,30 mm标准量块长度测量误差小于等于0.06 mm。

In the field of three-dimensional imaging,the accurate dephasing of wrapped phase is an important research area.Branch-cutting and least-squares methods are used to depict the phase diagram of the parcel phase with a single frequency.However,due to the influence of noise or shadow,branch-cutting method tends to produce an“island”effect,and results obtained using the least-squares method may deviate from the true value of the phase.Consequently,a phase unwrapping algorithm based on central curl segmentation is proposed.It calculates the central curl of each pixel in the parcel phase map,divides the area with a central curl of 0 and the area without 0,solves the parcel phase wrap using flood filling and second-order differential reciprocal sorting,and performs phase uplift processing at the regional boundary to obtain a complete absolute phase map.Simulation results reveal that the unwrapping performance of the algorithm proposed herein is remarkably better than that of the branch-cutting and least-squares methods.Experimental results reveal that the phase unwrapping algorithm based on central curl segmentation can effectively achieve the three-dimensional imaging for the surface contour information of the measured object.Moreover,the three-dimensional measurement error of the blade surface is≤0.08 mm,and the measurement error of length for the 30-mm standard gauge block is≤0.06 mm.