Research Inst. of Robotics, Shanghai Jiaotong Univ. , Shanghai 200030, China;
Research Inst. of Robotics, Shanghai Jiaotong Univ. , Shanghai 200030, China;
Center for Intelligent Maintenance, Univ. of Wisconsin at Milwaukee, Milwaukee, WI 53211 USA;
ball gird array; machine vision system; coplanarity; image processing;