光栅相移法用于三维人体测量的实验研究

Experimental study of grating phase-shifting profilometry for body measurement

根据光栅相移法的基本原理,通过数字投影仪和数码相机构建了低成本的人体测量实验验证系统。为消除近心交叉光轴系统存在的非线性测量误差,采用平行光轴系统设计并运用投影仪移轴和相机区域拍摄技术,扩大了有效测量区域,同时对系统的标定以及投影光栅的设计原则给予详细的描述。阐述了四步相移法测量人台的实验过程,获得的条纹图像通过处理与计算,运用基于二阶差分的区域增长抗噪算法进行相位展开,并且采用阈值平均法对该算法进行优化,较好地避免了噪声对相位解算的影响,最后前后面点云数据进行拼接实现了人台的虚拟还原。

Based on the fundamental principle of grating phase-shifting algorithm, a low-cost 3-D body measurement experiment system was constructed by digital projector and digital camera. The parallel axis system which can avoid the nonlinear error caused by near core cross-axis system was adopted in combination with projector axis shift and camera local area shooting techniques to expand the effective measurement area. Description of calibration of the system and the design principle of the projection grating were given. The four-step phase-shifting algorithm experiment was carried out for measuring a dummy and the fringe images obtained were processed and calculated, and phase unwrapping was conducted by a second difference region-growing anti-noise algorithm which was optimized by averaging the threshold value to avoid the noise. And finally, the virtual dummy has been constructed by splicing the front and back cloud data.