Research On Stereovision Measurement Method Based On Circular Targets Building Planar

With the innovation and progress of science and technology, binocular stereovision measurement has been more and more used to the field of civil engineering, compared with the traditional contact measurement, binocular stereovision measurement have the characteristics of non-contact, whole process and high precision. In order to make the precision of binocular stereovision measurement higher, application more widely, this paper studies the stereovision measurement based on circular targets, make the related method into software, convenient for measuring structure.The main content introduced as below:Firstly, the premise condition to get the target displacement of traditional stereovision measurement is the world coordinate system is built on the left camera optical center. if the world coordinate system from the left camera optical center removed to the surface of structure, the transition matrix M should be obtained. This paper propose two methods of solving the transformation matrix M. The methods are calibration board to establish plane and circular target to establish plane. If the target is not in the same plane, the calibration plate is used to establish plane. if the targets are in the same plane, and not collinear circular targets are more than 6, the targets are used to establish plane. Transformation matrix M remove the world coordinate system to the surface of structure from the left camera optical center.Secondly, subarea search method based on forecast movement range is proposed. In order to solve the question of traditional stereovision measurement that data processing efficiency is low and error matching, this paper propose sub-area DIC search based on forecast movement range. The search area is reduced, the search time reduced to 1/10 of the original, at the same time, avoid error matching phenomenon appeared in the process of search. In order to measure the deformation of structure more convenient, the algorithm proposed in this paper compiled into software on the MATLAB platform.Thirdly, finish the wind and waves test of semi-submersible floating foundation. Calibration plate is used to establish plane for obtaining transition matrix M. World coordinate system removed to the surface of structure from left camera optical center. Through a formula of six degree of freedom obtain angle of rotation. Finish a monitoring test of concrete-filled steel tube arch, targets is used to establish plane for obtaining transition matrix M, Verify the reliability and validity of the proposed method. Finish 304 stainless steel tensile test, introducing polar constraint in the process of stereo matching, to improve the accuracy of stereovision measurement method.