Garnica G, Padilla M, Servin M
Appl Opt. 2017 Oct 1;56(28):7985-7989. doi: 10.1364/AO.56.007985.
A dual-sensitivity profilometry technique based on defocused projection of binary fringes is presented. Here, two sets of fringe patterns with a sinusoidal profile are produced by applying the same analog low-pass filter (projector defocusing) to binary fringes with a high- and low-frequency spatial carrier. The high-frequency fringes have a binary square-wave profile, while the low-frequency binary fringes are produced with error-diffusion dithering. The binary nature of the binary fringes removes the need for calibration of the projector's nonlinear gamma. Working with high-frequency carrier fringes, we obtain a high-quality wrapped phase. On the other hand, working with low-frequency carrier fringes we found a lower-quality, nonwrapped phase map. The nonwrapped estimation is used as stepping stone for dual-sensitivity temporal phase unwrapping, extending the applicability of the technique to discontinuous (piecewise continuous) surfaces. We are proposing a single defocusing level for faster high- and low-frequency fringe data acquisition. The proposed technique is validated with experimental results.
提出了一种基于二元条纹散焦投影的双灵敏度轮廓测量技术。在此，通过对具有高频和低频空间载波的二元条纹应用相同的模拟低通滤波器（投影仪散焦），生成两组具有正弦轮廓的条纹图案。高频条纹具有二元方波轮廓，而低频二元条纹通过误差扩散抖动产生。二元条纹的二元性质消除了对投影仪非线性伽马校准的需求。使用高频载波条纹时，我们获得了高质量的包裹相位。另一方面，使用低频载波条纹时，我们发现了质量较低的非包裹相位图。非包裹估计用作双灵敏度时间相位展开的垫脚石，将该技术的适用性扩展到不连续（分段连续）表面。我们提出了单个散焦级别，以更快地采集高频和低频条纹数据。所提出的技术通过实验结果得到了验证。
