用于非均匀条纹的二值时空编码相位展开方法

Binary spatiotemporal encoded method used for uneven fringes phase unwrapping

  • 摘要: 为解除现有非均匀条纹解相位方法对系统测量精度的限制,提出一种非均匀条纹的二值时空编码解相位方法。由标准非均匀条纹的截断相位反求截断相位分界线,对分界线进行二值编码与解码。采用四步相移法,只需三幅辅助编码图像即可准确获得非均匀条纹的绝对连续相位。建立非完全约束系统,利用二次多项式拟合绝对相位与物体深度关系,通过仿真实验与现有方法比较,拱桥形物体各对称点高度差值的均值和均方差分别降低了65%和51%;长方体测量误差的均值和均方差分别降低了95%和90%;同时,利用该方法对实际长方形物体表面进行测量,与三坐标测量仪的测量结果比较,平均误差仅为0.64%。实验结果表明:所述方法可提高非均匀条纹相位展开质量,在减少投影图像幅数的情况下,提高测量精度。

     

    Abstract: A binary spatiotemporal encoded method for uneven fringes phase unwrapping was proposed to remove the limitation of the existing non-uniform striped phase unwrapping method. From the standard non-uniform stripes cut off the phase reverse to cut off the phase line, the boundary line for binary coding and decoding.By using four step phase shifting method, the absolute phase of deformed uneven fringes can be obtained with three pieces of aided coding patterns. The nonholonomic system was established, and the relationship between the absolute phase and the depth of the object was fitted by quadratic polynomial. Compared with existing methods in simulation environment, the improved amount of average and standard deviation of all symmetric points height difference of arch object are 65% and 51% respectively. The improved amount of average and standard deviation for arch cuboid are 95% and 90% respectively. At the same time, the method is used to measure the surface of the rectangular object, which average error is only 0.64%, compared with the measurement results of the Coordinate Measuring Machine(CMM). The experimental results show that the method can improve the quality of uneven fringes phase unwrapping, and improve the measurement accuracy under the condition that the number of aided coding pattern is not increase.

     

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