Patent ID: 11935266
Assignee: NEC CORPORATION
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G  H | IPC G

Claim 6:
7. A non-transitory computer-readable recording medium that includes a program recorded thereon, the program including instructions that causes a computer to carry out:
taking three sets of three-dimensional coordinates pertaining to an object captured by a camera and two-dimensional coordinates corresponding to respective ones of the three-dimensional coordinates in an image that has been captured, and transforming a coordinate system of the three-dimensional coordinates from a world coordinate system to a local coordinate system that takes one of the three-dimensional coordinates as an origin;
calculating a linear transformation matrix on the basis of a projection transformation expression from the three-dimensional coordinates transformed into the local coordinate system to the two-dimensional coordinates, calculating a coefficient of a quartic equation pertaining to any one of depths from a center of the camera to respective ones of the three-dimensional coordinates, and calculating each of the depths by solving the quartic equation;
calculating a rotation matrix of the camera in the local coordinate system using the respective depths and the linear transformation matrix;
calculating a translation vector of the camera in the local coordinate system from the respective depths on the basis of the projection transformation expression; and
calculating a rotation matrix and a translation vector of the camera in the world coordinate system by performing an inverse transform of the rotation matrix and the translation vector of the camera in the local coordinate system.