【摘要】 基于离焦深度法设计了自动对焦光路,光路由激光光源,准直扩束透镜,调焦透镜,摄像头组成。使用ZEMAX软件模拟了对焦过程,通过控制调焦透镜的位置获取光斑半径,计算对焦位置。移动调焦透镜,分别在距离对焦目标5.62 cm,7.38 cm,14.02 cm,16.88 cm,20.94 cm处得到了弥散光斑的直径。计算得到的误差在1 mm以内。基于此,实际搭建了对焦光路并进行模拟。采用位移滑轨模拟透镜的变焦运动,由摄像头获取物面上的激光斑点,通过MATLAB编程来快速获得光斑直径的之间的比例。结果显示,对焦结果误差在1 cm以内,考虑到导轨读数存在误差,摄像头像素有限,激光功率不稳定等原因,虽然实际结果与理论模拟之间存在差异,但证实了此方法的可行性。后续工作将用位移平台替换手动滑轨,编程精密控制透镜的移动位置,实现自动对焦。研究工作为改进本课题组已经开发的便携式高灵敏毒品荧光检测系统提供技术参考。更多还原

【Abstract】 In this paper,based on the depth from defocus method,we design an automatic focusing optical path,including laser,collimation lens,focusing lens and CCD camera.ZEMAX software is utilized to simulate the optical path of the focusing process,through which the error is estimated within 1 mm,when the distances of focus target are 5.62 cm,7.38 cm,14.02 cm,16.88 cm and 20.94 cm.In this basis,the focal optical path is constructed and simulated.Meanwhile the diameters of the light spots are measured through a camera and analyzed by MATLAB software,which shows an error within 1 cm.Both simulation and experimental results demonstrate the feasibility of the depth from defocus approach to fulfill the auto-focusing process,in consideration of the error of the guide reading,the limited camera pixel and the unstable laser power.The subsequent work will replace the manual slide rail with the displacement platform,and the program will control the moving position of the lens and realize automatic focusing.The research work provides a technical reference for improving the portable and high sensitive narcotics fluorescence detection system.更多还原