计量型紫外显微镜实时焦点及倾角测量算法的研究

计量型紫外光学显微镜采用248 nm深紫外光源和高数值孔径物镜系统,工作距离和景深均很小,为实现清晰的成像,需要进行自动聚焦。因此研究了一种焦点及倾角测量算法,采用基于图像处理的自动聚焦方法,选择Tenengrad函数作为图像清晰度判据,进行清晰度评价。针对在扫描测量时标准样板倾斜与镜片可能会出现相撞的问题,提出了样板倾角测量方法来判断样板的倾斜方向和角度,从而确定物镜执行器的移动方向,实现物镜扫描成像过程中的动态对焦。

The Research of Real-time Focusing and Inclination Angle Measurement on Metrological Ultraviolet Microscope

The metrological ultraviolet microscope utilizes 248nm ultraviolet light illumination and high numerical aperture objective systems, the working distance and depth of field are very small. In order to achieve a clear image, it is required the automatic focus. An auto-focus and inclination measurement algorithm is researched. Using the automatic focusing method based on image processing, the Tenengrad function is selected as the image clarity criteriont. To solve the problem that the standard model tilt and the lens may collide during the scanning measurement, a method of measuring the inclination of the template is proposed to judge the inclination angle and direction of the template, and the real-time focusing is realized.