自动调焦在单目测距方法中的研究  

Study on Monocular Distance Measurement Based on Auto Focus

作　　者：任工昌[1] 刘崇展 刘朋[1] 张戈[1] REN Gong-chang;LIU Chong-zhan;LIU Peng;ZHANG Ge(School of Mechatronics Engineering, Shaanxi University of Science and Technology, Shaanxi Xi’an 710021, China)

机构地区：[1]陕西科技大学机电工程学院,陕西西安710021

出　　处：《机械设计与制造》2019年第4期146-149,共4页Machinery Design & Manufacture

基　　金：国家自然科学基金项(51175314);陕西省教育厅基于摄像技术的智能化项目(15JK1079);陕西省农业科技创新项目(2010NKC-32)

摘　　要：针对传统测距技术和自动调焦方法的局限性,从光学系统的成像理论出发,在图像处理的基础上,提出一种以变焦镜头为图像采集设备、基于物距与电机脉冲数定量关系的单目视觉测距新方法。该方法根据光学成像原理,计算不同物距下目标图像的清晰度值,根据改进的粗精变步长爬山搜索策略实现自动对焦,记录步进电机转向及脉冲个数,建立脉冲数与物距的定量关系,实现测距。以粮仓为例验证了该方法的可行性和有效性,且相对误差小于3%、方差小于0.702,满足精确度和稳定性要求,避免了复杂的摄像机标定,计算简单且易于实现。In view of the limitations of traditional ranging technology and automatic focusing method, based on the imaging theory of optical system, a new method of monocular vision ranging based on the quantitative relationship between object distance and motor pulse number and a zoom lens for image acquisition equipment is proposed. According to the principle of optical imaging, the sharpness value of the target image is calculated, and the auto focus is recorded according to the improved coarse and fine step-by-step climbing search strategy. The stepping motor steering and the number of pulses is recorded, the quantitative relationship between the pulse number and the material distance is established, distance measurement is achieved. The feasibility and validity of the method are verified by the granary as an example. The relative error is less than 3% and the variance is less than 0.702, which satisfies the accuracy and stability requirements. The complicated camera calibration is avoided and is simple and easy to implement.

关 键 词：单目测距 图像处理 自动对焦 搜索算法 变焦镜头 定量关系 

分 类 号：TH16[机械工程—机械制造及自动化] TH741