Abstract:A simple portable and large-range on-line measurement system was presented based on monocular vision for surface reconstruction.When the rigid body measuring head of the auxiliary target contacted perpendicularly with the measured point surface, the switching on the measuring head synchronously controlled camera to obtain the target mark image information. Further by computer image processing, the index point image plane coordinates were gotten, At last through coordinate transformation, the 3D coordinates of the object to be measured could be gotten. System calibration can improve the measurement accuracy. Through the camera transfer station, the optimal viewpoint planning analysis is realized, so the measurement range and degree of automation are improved. In addition, the measurement uncertainty of the system was discussed and the improvement measures were proposed.