相移法光栅投影3维物体表面重建中一种消除交叠的算法

An Algorithm for Discriminating Overlapped Stripes in 3D Object Reconstruction Using Phase-Shifting Raster Projection

光栅投影成像是3维物体重建和测量的重要技术。它将广泛应用于科学研究、生产、文化艺术、医学等各个领域。目前,这项技术的自动化程度较低,速度较慢。因此,对其研究具有重要的理论意义和实用价值。首先介绍了光栅投影成像和3维物体重建的基本原理,然后提出了利用光栅投影条纹编码、解码、相移技术和莫尔法相位解缠确定3维物体深度信息的方法。光栅投影条纹采用逐步二分的二进制7位码编码,相移采用间隔π48步相移的正弦相移技术。此外,还提出了一种算法以消除因光栅条纹图像发生交叠而造成条纹解码产生的错码。这种算法利用各幅条纹编码图像中条纹位置的相关性,通过对条纹边界线灰度值的迭代,实现交叠条纹的区分。该算法加快了条纹解码和相位解缠速度,减少了存储量,提高了自动化程度和测量精度。

Raster projection imaging is an important technology for 3D object reconstruction and measurement. It will be applied widely in the fields of research, manufacturing, culture and art, medicine, etc. So far, the technology is still in low automation and low speed. Hence, its development is significant theorefically and practically. In this paper, the principles of raster projection imaging and 3D object reconstruction are introduced firstly. Then a method is proposed for determining the depth of 3D object surface using raster stripe encoding, decoding, phase shifting, and Moire phase unwrapping. The raster stripes are encoded in 7 digit binary codes obtained by bisection and the phase shifting is performed by a sine function of 8 step shifting in π/4 interval. In this paper, an algorithm is also proposed to avoid stripe decoding errors caused by the overlapping of raster projection stripes. The algorithm uses the position correlation of the stripes in raster projection sequential images and the intensity accumulation of the stripes to discriminate the overlapped stripes. The algorithm can speed up the stripe decoding and phase unwrapping, reduce required memory size, promote automation, and increase measurement precision.