基于格雷码和相移算法的动态三维测量技术

Dynamic Three-Dimensional Measurement Technology Based on Gray Code and Phase-Shifting Algorithm

格雷码辅助实现的相位测量轮廓术具有较好的鲁棒性和抗噪能力,是三维测量领域的一个研究热点。在已有测量方法的基础上,提出了一种把格雷码嵌入相移条纹进行复合图案投影的三维面形测量方法,通过将传统的3幅格雷码图案整体向右移动半个条纹周期,共得到6幅格雷码图,将其交替嵌入三组相同的四步相移条纹中并结合二值离焦技术依次进行投影。通过拍摄得到一系列变形复合条纹图案后,沿时序综合前后三组变形复合图案信息并进行解码,从而获得两组错位的条纹级次,这可从源头上避免格雷码级次边沿的错误;同时采用传统相移算法计算得到对应的截断相位分布,时序上的综合解码结果可用于指导截断相位产生并重建被测物体的三维面形信息。静态和动态场景的三维测量实验结果验证了该方法的可靠性、高效性和鲁棒性。该方法每多记录5幅图案就可以对应新重建出一个三维面形,在高速动态三维测量中具有较好的实用性。

Phase measurement profilometry based on Gray code has high robustness and anti-noise ability,and it is a major research hotspot in the field of three-dimensional(3 D)measurement.Based on the existing measurement methods,this paper proposes a 3 D shape measurement method via embedding the Gray code into the phase-shifting fringe for composite pattern projection.By moving the traditional three Gray code patterns to the right with the shift distance of half a fringe period,six Gray code patterns are obtained,which are alternately embedded into three groups of the same four step phase-shifting fringes and projected in turn combined with binary defocusing technology.After a series of deformed composite fringe patterns are captured,the information of the three groups of deformed composite patterns is synthesized and decoded along the time sequence to obtain two groups of staggered fringe levels,which can avoid the error of Gray code order edge from the source;at the same time,the corresponding truncated phase distribution is calculated by using the traditional phase-shifting algorithm,and the comprehensive decoding results on the time sequence can be used to guide the generation of truncated phase and reconstruct the 3 D shape information of the object to be measured.Experimental results of 3 D measurement of static and dynamic scenes verify the reliability,efficiency,and robustness of the method.This method can reconstruct a new 3 D surface shape for every five more patterns recorded,which has good practicality in high-speed dynamic 3 D measurement.