基于评价函数的光电定焦方法研究

Study on Photoelectric Focusing Method Based on Evaluation Function

以CCD和透镜作为光学成像系统,并以高斯公式作为基本测量原理,提出了基于定焦评价函数的图像处理方法来寻找光学系统的最清晰像面位置,以实现光学系统的自动定焦。实验选用了绝对方差函数、梯度向量模函数、梯度向量平方函数三种评价函数进行了验证,经过逐次逼近,确定出最清晰的像面位置。实验数据显示,定焦精度可达0.01mm。

The Gauss Formula as the basic measuring principle in a CCD optical imaging system was adopted. A method was proposed that utilizing the image processing focusing evaluation function to finding a clear image plane＇s location. In order to realize the automatic focusing in the optical system. By using absolute variance function, gradient vector modulus function and gradient vector square function, the three kinds of evaluation functions in this experiment, and then successively approx- imate, which can determin the most clear image plane＇s location at last. The results indicate that the focusing accuracy can reach O. O1 mm.