基于虚拟视野的结构光条纹投影像素精准映射方法

Research on the pixel accurate mapping method of structured light fringe projection based on virtual field of vision

针对像素尺寸差异、相位误差等导致相机与投影仪同名点像素坐标匹配错误、有效像素点缺失问题,提出一种基于虚拟视野的改进包裹相位-坐标映射方法。首先,对不同重叠视场下的条纹信息进行分析,确定较优投影模式;其次,设计两组高低频率的横纵条纹,提取低频相位极值计算虚拟投影视野、高频周期对真实和虚拟视野逐级编号,实现视野小范围匹配;最后,改进包裹相位坐标映射方法和相位差阈值判别准则,逐编号求解投影像素坐标,获得像素间的精准映射关系。实验结果表明,相位中相同像素区间的包裹相位均方根误差,相较于连续相位降低了78.6%。在平面和复杂表面实验中,有效像素数量相较于传统匹配增长了9.21倍和9.43倍,像素误匹配坐标比例由传统相位匹配的80.55%、59.4%降低至14.26%、12.56%,为自适应条纹测量技术中像素同名点匹配提供了可行的解决方案。

To solve the problem of pixel coordinate mismatch and effective pixel missing caused by pixel size difference and phase error between camera and projector,an improved wrapping phase-coordinate mapping method based on virtual field of view is proposed.Firstly,the fringe phase under different overlapping field of view is analyzed to determine the optimal projection mode.Secondly,two sets of horizontal and vertical fringes with high and low frequencies are designed,and the low frequency phase extremum is extracted to calculate the virtual projection field of view.The high frequency period numbered the real and virtual field of view step by step to realize the coarse matching between the small field of view.Finally,by using the improved wrapping phase coordinate mapping method and the criterion of phase difference threshold,the projection pixel coordinates are numbered to obtain the accurate mapping relationship between pixels.Experimental results show that the enveloping phase root mean square error in the same pixel interval is reduced by 78.6%compared with the continuous phase.In planar and complex surface experiments,the number of effective pixels increases by 9.21 times and 9.43 times compared with traditional matching.The proportion of pixel mismatched coordinates decreases from 80.55%and 59.4%of traditional phase matching to 14.26%and 12.56%.It provides a feasible solution for pixel matching with the same name in adaptive fringe measurement technology.