三维面形测量中结构光场的非线性分析和校正

Analysis and correction of the nonlinearity of the structured light illumination in three-dimensional shape measurement

在基于数字投影的结构光三维面形测量中,相位测量轮廓术和傅立叶变换轮廓术是两种重要的方法,但由于受到CCD探测器光电响应的非线性、投影伽马的非线性以及环境光照等因素的影响,引起投影条纹正弦性的下降,最终导致相位和重建面形的误差。本文提出一种实用的结构光场生成方法,有效改善了结构光场的正弦性。从成像系统出发,通过理论推导,计算机模拟和实验,结果表明该方法大大降低了投影伽码引起的非线性误差,相位误差的标准偏差降低了7倍。

The phase measuring profilometry and Fourier transform profilometry are two important methods of 3 - D shape measurement based on structured light illumination. But the nonlinear of CCD detector,the gamma of the projector will impact the stmcturod light illumination and lead to a decline the quality of the fringe pattern,also lead to the error of phase calculation and shape reconstruction. This paper presents a practical method to generate the structured light illumination with good sinusoidal characteristic. The results of the theoretical analysis, computer simulation and actual - experiment show that this raethod can greatly reduce the phase error caused by the projector gamma nonlinearity, and this practical method can decrease the standard deviation of the phase error by 7 times.