Wan Yingying, Cao Yiping, Liu Xinran, Tao Tianyang, Kofman Jonathan
Opt Express. 2020 Apr 27;28(9):13043-13058. doi: 10.1364/OE.388579.
In multi-view fringe projection profilometry (FPP), a limitation of geometry-constraint based approaches is the reduced measurement depth range often used to reduce the number of candidate points and increase the corresponding point selection reliability, when high-frequency fringe patterns are used. To extend the depth range, a new method of high-frequency fringe projection profilometry was developed by color encoding the projected fringe patterns to allow reliable candidate point selection even when six candidate points are in the measurement volume. The wrapped phase is directly retrieved using the intensity component of the hue-saturation-intensity (HSI) color space and complementary-hue is introduced to identify color codes for correct corresponding point selection. Mathematical analyses of the effect of color crosstalk on phase calculation and color code identification show that the phase calculation is independent of color crosstalk and that color crosstalk has little effect on color code identification. Experiments demonstrated that the new method can achieve high accuracy in 3D measurement over a large depth range and for isolated objects, using only two high-frequency color-encoded fringe patterns.
在多视图条纹投影轮廓术（FPP）中，基于几何约束的方法存在一个局限性，即当使用高频条纹图案时，为了减少候选点数量并提高对应点选择的可靠性，通常会减小测量深度范围。为了扩展深度范围，开发了一种新的高频条纹投影轮廓术方法，通过对投影条纹图案进行颜色编码，即使测量体积中有六个候选点，也能实现可靠的候选点选择。利用色相 - 饱和度 - 亮度（HSI）颜色空间的强度分量直接获取包裹相位，并引入互补色相来识别颜色编码，以进行正确的对应点选择。对颜色串扰对相位计算和颜色编码识别影响的数学分析表明，相位计算与颜色串扰无关，且颜色串扰对颜色编码识别影响很小。实验表明，该新方法仅使用两个高频颜色编码条纹图案，就能在大深度范围内对孤立物体实现高精度的三维测量。
