基于线阵CCD传感器的激光标印机自动对焦系统研究  

Design of Auto-focus System Based on CCD Sensor Laser Marking Machine

作　　者：杜笑滢 姜涛[1,2] 张桂林 DU Xiaoying;JIANG Tao;ZHANG Guilin(School of Mechanical and Electrical Engineering,Changchun University of Science and Technology,Changchun 130022;Chongqing Research Institute,Changchun University of Technology,Chongqing 401135)

机构地区：[1]长春理工大学机电工程学院,长春130022 [2]长春理工大学重庆研究院,重庆401135

出　　处：《长春理工大学学报（自然科学版）》2021年第6期76-83,共8页Journal of Changchun University of Science and Technology(Natural Science Edition)

基　　金：吉林省省级产业创新专项资金项目(2017C045-2)。

摘　　要：针对工业中使用的标准激光标印机仍使用手动对焦方式,存在离焦量计算不准确、手动对焦随机误差大、对焦时间长等缺陷,基于偏心光束原理,设计一种以TCD1209D线阵CCD传感器为核心的自动对焦系统。建立光斑图像信息与激光标印系统离焦量间的数学关系,设计以DSP控制器为核心的信号处理系统,通过控制器产生CCD驱动脉冲,获取光斑信息经A/D转换器输入DSP控制器并依据函数关系计算得到系统离焦量,进而控制对焦平台实现自动对焦任务。结合实验分别探究光斑图像重心坐标、宽度与离焦量间的函数关系,实验结果显示图像宽度与离焦量可拟合为线性函数关系,其动态对焦范围为±240μm,对焦精度可达4μm,与手动对焦模式相比极大提高对焦精度。In recent years,high-precision and fast focusing systems had been widely used in the biomedical field.However,manual focusing methods were still used in ordinary laser marking machines of the industry,which had inaccurate calculations of defocus,large random errors in manual focusing,long focusing time,etc.Designing the auto-focus module of the laser marking system was the key to improving the quality and efficiency of marking.Based on the principle of eccentric beam,an autofocus system structure with TCD1209 D linear CCD sensor as the core was designed.The mathematical relationship between the image information of the light spot and the defocus of the laser marking system was established.A signal processing system with a DSP controller as the core was designed,and the DSP controller was used to generate CCD drive pulses,and the light spot information was obtained by the CCD sensor and input through the A/D converter.The defocusing amount of the system was calculated by the DSP controller according to the functional relationship;and the focusing platform motor was controlled to realize the autofocus task.The function relationship between the center of gravity coordinates,width and defocus of the spot image was explored through experiments.It was found that the image width and defocus could be fitted as a linear function.The dynamic focus range was±240μm;and the focus accuracy reached 4μm.Compared with the focus mode,the focus accuracy was greatly improved.

关 键 词：自动对焦 线阵CCD 线性关系 

分 类 号：TP272[自动化与计算机技术—检测技术与自动化装置] TH744[自动化与计算机技术—控制科学与工程]