在模拟分析投影仪伽马非线性对相位误差影响的基础上,提出一种直接分析投影光栅特征并建立相位误差查找表的算法,对相位误差进行补偿。该算法通过分析一组投射到标准白色平板上的光栅图像,确定光栅相位值与相位误差的对应关系,并量化存储在一个查找表中,测量过程中使用查找表对相位误差进行补偿。实验结果表明,该方法可大大降低由投影仪伽马非线性引起的相位误差,系统测量精度达到0.043 mm,比误差补偿前提高了5.6倍。

Based on simulation of the impact of gamma nonlinearity of the projector on phase error, an algorithm is proposed to build a look-up table (LUT) for phase error compensation by analyzing the projector grating directly. In this algorithm, a set of grating images of a uniform flat surface board are captured and the relation of grating phase and phase error in established. Then the relation is analyzed and stored in a LUT for phase error compensation. Experimental results show this algorithm reduces greatly the phase error caused by the gamma nonlinearity of the projector. The measurement precision of the system reaches 0.043 mm, 5.6 times higher than that before error compensation.