基于正交双目视觉的药液杂质粒径标定  

Particle size calibration of impurities in bottled liquid based on orthogonal binocular vision

作　　者：李伟[1] 王伯雄[1] 杨春毓[1] 

机构地区：[1]清华大学精密仪器与机械学系精密测试技术及仪器国家重点实验室,北京100084

出　　处：《光学精密工程》2013年第10期2603-2609,共7页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.11274199)

摘　　要：灯检机是利用机器视觉技术对药液中可见异物进行检测的机器。为了利用全自动灯检机获取中药液杂质粒径和其成像大小之间的精确标定曲线,提出了基于正交双目视觉的杂质粒径标定方法。首先,根据空间匹配建立杂质颗粒在正交相机图像中的对应关系,得到杂质颗粒在图像中的三维空间坐标;然后,根据杂质颗粒的坐标计算由柱形瓶装药液带来的一维放大率误差并对杂质颗粒图像进行图像几何校正,再根据杂质颗粒坐标进行杂质离焦误差系数计算,从而获得杂质颗粒图像大小的精确值。对滴加了粒径为50μm的标准颗粒的西林水剂瓶进行粒径标定,使杂质粒径测定值的离散度系数从0.11降低到了0.05。实验表明,此方法可以获得高精度的粒径标定曲线,实现灯检机对药液中杂质粒径的精确判定。Light inspection machine is a detecting instrument for visible impurities in liquid by machine vision technology.In order to establish a calibration curve between the particle sizes of impurities in the liquid and their image sizes in the intelligent inspection machine,a calibration method of particle sizes was proposed based on orthogonal binocular vision.First,the correspondence relationship of the impurities in the orthographic camera images was created based on the image spatial location matching and 3D spatial coordinates of the impurity particles in images were obtained.Then,according to the obtained three-dimensional coordinates of the impurity particles in liquid images,one-dimensional magnification errors of cylindrical liquid were calculated,the geometric correction of impurity particle images was completed and the defocused error coefficient was also obtained.Furthermore,the precise values of image sizes of the impurity particles were calculated.Finally,the standard particles with a diameter of 50 μm in a penicillin bottle were calibrated.Calbiration results show that the dispersion coefficients of impurity particle sizes are reduced from 0.11 to 0.05.The experiments indicate that this method can get a particle size calibration curve with a high precision and can help the light inspection machine to measure the particle sizes of impurities in the liquid accurately.

关 键 词：灯检机 粒径标定 正交双目视觉 图像几何校正 离焦误差 

分 类 号：TH821[机械工程—仪器科学与技术] TP242.62[机械工程—精密仪器及机械]