光学元件激光损伤在线检测装置

设计并搭建了一套光学元件表面损伤检测装置，用于激光损伤实验中光学元件表面损伤的自动化在线检测。装置主要由自动变倍显微相机、高精度位移传感器、两维扫描轴、调焦轴、快速复位平台和系统控制器组成。两维扫描轴按照规划好的弓形路径对光学元件表面激光辐照区域进行扫描，调焦轴对位移传感器反馈的离焦量进行实时修正，显微相机采集子图像并进行保存。首先，分析影响图像拼接精度的主要误差源并通过图像矫正等方法进行补偿；然后，利用图像拼接技术将矫正后的子图像矩阵进行高精度无缝拼接，得到大面积高分辨率的光学元件表面损伤图像；最后，对损伤图像进行后处理得到损伤个数和损伤面积等信息。实验结果表明:装置在5 min内实现了光学元件表面15 mm15 mm区域的扫描拼接和检测，成像系统分辨率优于228 lp/mm，图像拼接误差小于2 pixel。

An online laser-induced flaw inspection device for optical elements

The laser-induced damage experiments are very important to verify the reliability and lifespan of the optical elements. The optical elements are irradiated by the high energy laser frequently and the corresponding damage information is recorded by the researchers. A device was designed and constructed to inspect the surface flaws of the optical elements on line efficiently and automatically. The device was composed of six parts, which were automatic zoom microscopic camera, spectral confocal sensor, two dimensional scan movement axes, focus movement axis, fast reset platform and system controller. The laser irradiated area of the optical elements was scanned by the two dimensional scan movement axes according to the planned path. The work distance of the microscope was detected by the spectral confocal sensor and adjusted by the movement of the focus axis. The sub images were acquired by the microscopic camera and saved to the computer. Firstly, the main error factors that affect the image matching precision were analyzed and compensated by the image correction and so on. Then the image with large area and high resolution was obtained by stitching the corrected sub images. Lastly, the damage information was obtained after image processing. The experimental results show that the time is no more than 5 minutes to detect an area of 15 mm15 mm. The resolution of the microscope imaging system is better than 228 lp/mm and the stitching error is better than 2 pixel.