Abstract: The image capturing part 201 captures a ball in flight with a camera continuously. The image corresponding part 203 generates a first registered ball image obtained by making a size of a first ball image in a first capturing image captured first correspond to a size of a second ball image in a second capturing image captured second. The 3D model constructing part 204constructs a 3D model of the first registered ball image obtained by converting a camera coordinate system of the generated first registered ball image into a world coordinate system. The virtual rotating part 205 rotates virtually the constructed 3D model of the first registered ball image by using a rotation parameter estimated in advance and rotation matrix information.