Camera calibration method for dimensional measurement of heavy forging in large scale

摘要

Camera calibration method plays an important role in the stereovision system to resolve the problems of dimensional measurement of heavy forging. Due to the intensive vibrating, the camera parameters must be calibrated every time after the action of the water press. This paper presents a method using the scene geometry to calibrate cameras. In the context of heavy machinery environments, the constraints which can be used are parallelism and orthogonality. These constraints lead to geometrically intuitive methods to calibrate the cameras. The huge forging equipment such as water press belongs to geometrically constrained object and insusceptible to vibrating, which gives natural prior knowledge and constraint conditions for 3-D reconstruction. The method focuses on the calibration of the extrinsic parameters which are subject to change since the effects of the workspace factors. The intrinsic parameters were calibrated in advance by an off-line method and were assumed as invariable. The results of simulation experiments demonstrate that the camera parameters could be calibrated effectively and achieve the real time need.