Xu Ying, Ekstrand Laura, Dai Junfei, Zhang Song
Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, USA.
Appl Opt. 2011 Jun 10;50(17):2572-81. doi: 10.1364/AO.50.002572.
This paper analyzes the phase error for a three-dimensional (3D) shape measurement system that utilizes our recently proposed projector defocusing technique. This technique generates seemingly sinusoidal structured patterns by defocusing binary structured patterns and then uses these patterns to perform 3D shape measurement by fringe analysis. However, significant errors may still exist if an object is within a certain depth range, where the defocused fringe patterns retain binary structure. In this research, we experimentally studied a large depth range of defocused fringe patterns, from near-binary to near-sinusoidal, and analyzed the associated phase errors. We established a mathematical phase error function in terms of the wrapped phase and the depth z. Finally, we calibrated and used the mathematical function to compensate for the phase error at arbitrary depth ranges within the calibration volume. Experimental results will be presented to demonstrate the success of this proposed technique.
本文分析了一种利用我们最近提出的投影仪散焦技术的三维（3D）形状测量系统的相位误差。该技术通过对二进制结构化图案进行散焦来生成看似正弦的结构化图案，然后利用这些图案通过条纹分析来进行3D形状测量。然而，如果物体处于某个深度范围内，散焦条纹图案仍保持二进制结构，则可能仍然存在显著误差。在本研究中，我们对从近二进制到近正弦的大深度范围的散焦条纹图案进行了实验研究，并分析了相关的相位误差。我们根据包裹相位和深度z建立了一个数学相位误差函数。最后，我们校准并使用该数学函数来补偿校准体积内任意深度范围内的相位误差。将给出实验结果以证明该技术的成功。
