Depth camera calibration using 4 spheres on tetrahedron corners

Abstract

In this study, a system including 4 depth cameras (Kinect v1) was constructed for 3-dimensional reconstruction of an object. As with all cameras, the calibration parameters of the cameras used must be known in order to transform from image coordinates to world coordinates in depth cameras. Contrary to the studies that use flat calibration objects such as checkerboard and infrared images, which are frequently encountered in the literature, in this study, only depth images of the cameras were used to find intrinsic and extrinsic parameters of a depth camera. For the calibration process, a new tetrahedron calibration object with 4 equiradius spheres was designed, the sphere centers were determined in the world and image coordinates, and the projection matrix method was applied. The minimum number of matching points required by the original projection matrix method was reduced from 6 to 4 with the help of depth information. A new calibration object and method was developed to provide successful 3-dimensional reconstruction results of 4 depth cameras with the use of only 4 matching points and can be used in all types of depth cameras.