Multiple-phase-shifted structured light illumination achieves high-accuracy 3D reconstructions of static objects, while typically it can’t achieve real-time phase computation. In this paper, we propose to compute modulations and phases of multiple scans in real time by using divide-and-conquer solutions. First, we categorize total N = KM images into M groups and each group contains K phase equally shifted images; second, we compute the phase of each group; and finally, we obtain the final phase by averaging all the separately computed phases. When K = 3, 4 or 6, we can use integer-valued intensities of images as inputs and build one or M look-up tables storing real-valued phases computed by using arctangent function. Thus, with addition and/or subtraction operations computing indices of the tables, we can directly access the pre-computed phases and avoid time-consuming arctangent computation. Compared with K-step phase measuring profilometry repeated for M times, the proposed is robust to nonlinear distortion of structured light systems. Experiments show that, first, the proposed is of the same accuracy level as the traditional algorithm, and secondly, with employing one core of a central processing unit, compared with the classical 12-step phase measuring profilometry algorithm, for K = 4 and M = 3, the proposed improves phase computation by a factor of 6 ×.

中文翻译：

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分而治之：使用多相移结构光照明进行静态物体的实时高精度3D重建

多相移结构光照明可实现静态对象的高精度3D重建，而通常无法实现实时相位计算。在本文中，我们建议使用分而治之的解决方案实时计算多次扫描的调制和相位。首先，我们将总共N = KM个图像分类为M组，每组包含K个相移的图像。其次，我们计算每组的相位；最后，我们通过平均所有单独计算的相位来获得最终相位。当K = 3、4或6时，我们可以使用图像的整数强度作为输入并建立1或M查找表，该表存储使用反正切函数计算的实值相位。因此，通过对表的索引进行加法和/或减法运算，我们可以直接访问预先计算的阶段，从而避免了费时的反正切计算。与重复M次的K阶相位测量轮廓图相比，该方法对结构光系统的非线性失真具有鲁棒性。实验表明，首先，所提出的算法与传统算法具有相同的精度水平；其次，与经典的12步相位测量轮廓图算法相比，对于K = 4和M，采用中央处理器的一个核= 3时，建议将相位计算提高了6倍。