基于单目显微视觉的微球姿态测量方法

A Pose Measurement Method for Micro Sphere Based on Monocular Microscopic Vision

微零件的姿态测量对微装配具有重要的作用.但对于微球零件,其姿态的精确测量存在困难,影响了装配精度.针对带有微孔的微球,本文提出了一种基于单目显微视觉的微球姿态高精度测量方法.设计了一种由粗到精的微孔检测算法,实现了高精度的微孔定位.通过对相机光轴方向的标定,在相机运动后对微球图像坐标进行补偿,提高了在相机坐标系下的微球定位精度.通过对微球和微孔的精确定位,计算出微球球心与微孔圆心的空间相对位置,实现了相机坐标系下高精度的微球姿态测量.同时,根据标定出的相机坐标系与调整平台坐标系之间的旋转关系,将微球姿态转换到调整平台坐标系.实验结果表明,最大姿态测量误差0.3度,验证了本文方法的有效性.

Pose measurement for micro-components is very important to micro assembly.But it is quite difficult to measure the pose of a micro sphere with high precision,which impacts the assembly accuracy.An accurate pose measurement method for sphere with micro hole is proposed.A coarse-to-fine detection method is designed for the micro-hole on the micro-sphere.It realizes the high precision location of the micro-hole.The direction of the microscopic camera’s optical axis is calibrated.It is used to compensate the micro-sphere’s image coordinates after the microscopic camera moves in order to improve the location accuracy of the micro-sphere in the camera’s frame.The relative position between the center of sphere and the center of hole can be easily derived from the accurately located micro-sphere and micro-hole.Then the pose of micro-sphere can be gotten.Meanwhile,the pose of micro-sphere can be transformed from the camera’s frame into the frame of adjusting platform according to the calibrated rotation relationship between the two frames.The maximum error in pose measurements is 0.3 degree.Experimental results verify the effectiveness of the proposed method.