A method and system for automatic calibration of camera extrinsic parameters for building digital twins

Abstract

The present application provides a method and system for automatic calibration of camera external parameters oriented to architectural digital twins. The method includes: when the rotation angle of the camera angle of view satisfies the preset condition, three coordinates in the world coordinate system of the virtual space are determined from the target image frame Three vanishing points corresponding to the axis directions respectively, and establish the vanishing point world coordinate system according to the three vanishing points and the origin of the camera coordinate system; according to the vanishing point coordinates of the three vanishing points in the vanishing point world coordinate system, and from the line detection The pixel coordinates of the three vanishing points determined in the result in the pixel coordinate system determine the first rotation matrix; according to the target axis transformation adjustment relationship between the vanishing point world coordinate system and the virtual space world coordinate system, the first rotation matrix is ​​performed Coordinate transformation processing to obtain the target rotation matrix, so as to follow the rotation of the dynamic camera, and adaptively update the camera extrinsic calibration results.

Description

technical field [0001] The present application relates to the technical field of building digital twins, and in particular, to a method and system for automatic calibration of camera external parameters for building digital twins. Background technique [0002] Digital twin refers to making full use of physical model, sensor update, operation history and other data, integrating multi-disciplinary, multi-physical, multi-scale, multi-probability simulation process, and completing the mapping in virtual space, thus reflecting the full life of the corresponding physical equipment. cycle process. Among them, building digital twin refers to that in the application scenario of engineering construction, in order to display the spatial layout structure of the physical building more intuitively and clearly, the engineering construction personnel usually build a physical and functional characteristic of the physical building after the physical building is completed. The built building ...

AI Technical Summary

Problems solved by technology

The camera extrinsic parameters include the target rotation matrix and translation vector. For a dynamic camera, the camera position is determined, but the target rotation matrix will change as the camera rotates. If the camera extrinsic parameters cannot change in time with the camera rotation, then the camera coordinates When performing coordinate transformation between the virtual space world coordinate system and the virtual space world coordinate system, the conversion accuracy will be reduced, resulting in a decrease in the accuracy of the calculation results of the real position of the virtual object mapped by the entity object in the digital twin model, and the model in the constructed / updated digital twin model distorted information

Images