In order to enlarge the measurement range of stereo vision measurement system and realize the accurate measurement for large-scale workpiece,a 3-D connection method is proposed based on control net.The method constructs the measurement control net based on unit quaternions with the assistant measurement control points that are set around the measured workpiece,and optimizes the measurement precise of control net with Levenberg-Marquardt(LM) optimal algorithm.Then it transforms the measurement data in the lo...