一种激光三角测厚中非线性的校正方法

针对单镜头激光三角法测同一物体厚度时图像探测器上两光斑间距与被测物位置之间的非线性关系,提出了一种非线性校正方法,并用实验验证了校正效果。分析了单镜头激光三角法测厚原理,总结了引起非线性的因素,对校正方法的函数模型进行了理论推导,并对校正前后测量数据进行了详细分析。研究结果表明,使用该非线性校正方法后,图像探测器上成像光斑间距值随被测物位置变化的波动程度明显减小,测量厚度的均方差值也变小,系统的测量精度得到提高。

A nonlinear correction method for laser triangulation thickness measurement

For the nonlinear relationship between flare spacing on the image detector and the location of the object while metering the same measurand, a kind of nonlinear correction method is put forward and experiment duly conducted to verify the correction effect. The measurement principle of the single lens laser triangulation is discussed and the factors causing the nonlinear results are summarized, then, the function model of the correction methods is deduced, after that, the measured data before and after correction are analyzed in detail. The result proves that the fluctuation content of the flare spacing along the location of the object reduces significantly after adopting the nonlinear correction method, and the standard deviation value of the measure thickness becomes smaller, the measurement accuracy of the system is thus improved.