一种基于阶跃图像的条纹投影轮廓术校正方法

A fringe projection profilometry correction method based on step image

投影仪的非线性响应导致投影条纹图产生意外的变化,在条纹投影轮廓术中严重影响了最终的三维测量精度。以前的方法要么需要处理大量的图像,要么容易受到斜角投影的影响,而现有的伽玛校正方法并没有考虑到这一点。通过建立系统成像模型,分析了倾角投影对成像光谱的影响,提出一种基于阶跃成像的伽玛校正方法。由于数据在空间上的处理和阶跃图像的性质,该方法不需要计算就能实现对不同投影角度的伽玛参数进行可靠地估计。最后,通过实验验证了该方法的有效性。

The gamma nonlinear response of a projector makes the projected fringe patterns yield unexpected changes,which seriously affects the final three-dimensional measurement accuracy in fringe projection profilometry.Previous methods either need to process large numbers of images or are susceptible to oblique-angle projection that has not yet been taken into account in existing gamma correction methods.In this paper,a gamma correction method based on stepimages is presented by establishing a system imaging model and analyzing the effect of oblique-angle projection on imag⁃ing spectrum.Due to data processed spatially and the nature of step-images,this method can achieve a reliable estimate for the gamma in different projection angles without the need of computation.The validity of the method is verified by do⁃ing experiments.