提高数字光栅投影测量系统精度的gamma校正技术

gamma Correction Method for Accuracy Enhancement in Grating Projection Profilometry

数字光栅投影测量系统中存在的gamma失真现象会带来明显的测量误差。提出了一种基于投影光栅预编码的gamma校正技术,通过对投影光栅引入一个预编码值,将经过预编码调制后的投影光栅用于测量,极大地削弱了由gamma失真现象带来的影响,提高了测量精度。实验验证了该方法的有效性,将该gamma校正技术用于传统的相移算法。采用该方法求得的预编码值,对相移算法的投影正弦光栅进行预编码调制,调制后的相移算法精度得到极大提高。与已有的基于投影光栅预编码的gamma校正技术相比,所提方法简单且有效。

The gamma distortion in fringe projection profilometry system will create obvious measurement error.A gamma correction method based on the pre-coding of projected grating is proposed to reduce the measurement error caused by the gamma distortion.By applying an appropriate pre-coding value to the projected grating,the gamma distortion effect is attenuated and the accuracy is enhanced.Experiments are carried out to verify the proposed method.The traditional phase shifting profilometry is combined with the gamma correction method.Projected sinusoidal grating of the phase shifting profilometry are modulated by the appropriate pre-coding value.Then,accuracy of measurement of the phase shifting profilometry can be effectively enhanced.Compared with the existing pre-coding gamma correction method,the proposed method is simple and effective.