Flexible error-reduction method for shape measurement by temporal phase unwrapping: phase averaging method.
Flexible error-reduction method for shape measurement by temporal phase unwrapping: phase averaging method.
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DOI：
10.1364/ao.51.004945
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发表时间：
2012-07
期刊：
影响因子：
1.9
通讯作者：
L. Yong;Dingfa Huang;Jiang Yong
中科院分区：
文献类型：
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作者：
L. Yong;Dingfa Huang;Jiang Yong
时间相位解包裹是结构光投影法面形测量的一种重要方法。它的测量误差主要来自相机噪声和非线性。分析发现，最小二乘拟合虽然能显著减小随机误差，但不能完全消除非线性误差。为了进一步减小现有时间相位展开算法的测量误差，提出了一种相位平均法（PAM），该方法在数据处理过程中增加一个条纹密度最高的条纹序列，并根据相位非线性误差的周期来选择每组4帧的相位偏移量，基于快速经典时间相位展开算法。该方法通过统计平均，既能减小随机误差，又能减小系统误差。此外，附加条纹序列的长度可以根据测量精度灵活改变。理论分析和仿真实验结果表明了该方法的有效性。
Temporal phase unwrapping is an important method for shape measurement in structured light projection. Its measurement errors mainly come from both the camera noise and nonlinearity. Analysis found that least-squares fitting cannot completely eliminate nonlinear errors, though it can significantly reduce the random errors. To further reduce the measurement errors of current temporal phase unwrapping algorithms, in this paper, we proposed a phase averaging method (PAM) in which an additional fringe sequence at the highest fringe density is employed in the process of data processing and the phase offset of each set of the four frames is carefully chosen according to the period of the phase nonlinear errors, based on fast classical temporal phase unwrapping algorithms. This method can decrease both the random errors and the systematic errors with statistical averaging. In addition, the length of the additional fringe sequence can be changed flexibly according to the precision of the measurement. Theoretical analysis and simulation experiment results showed the validity of the proposed method.