State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan, China.
Opt Lett. 2011 Jan 15;36(2):154-6. doi: 10.1364/OL.36.000154.
In fast phase-measuring profilometry, phase error caused by gamma distortion is the dominant error source. Previous phase-error compensation or gamma correction methods require the projector to be focused for best performance. However, in practice, as digital projectors are built with large apertures, they cannot project ideal focused fringe images. In this Letter, a thorough theoretical model of the gamma-distorted fringe image is derived from an optical perspective, and a highly accurate and easy to implement gamma correction method is presented to reduce the obstinate phase error. With the proposed method, high measuring accuracy can be achieved with the conventional three-step phase-shifting algorithm. The validity of the technique is verified by experiments.
在快速相移轮廓术中，由伽马失真引起的相位误差是主要误差源。之前的相位误差补偿或伽马校正方法需要投影仪聚焦以获得最佳性能。然而，在实际中，由于数字投影仪采用大孔径设计，它们无法投影出理想的聚焦条纹图像。在本信中，从光学角度出发，推导出了伽马失真条纹图像的详细理论模型，并提出了一种高精度且易于实现的伽马校正方法，以减小顽固的相位误差。采用所提出的方法，即使使用传统的三步相移算法也可以实现高精度测量。通过实验验证了该技术的有效性。
