Patent Document ID: 20080075324
Application ID: 11658105
Patent Status: 0

Claim One:
1. A camera calibration system comprising: an image-capturing device; a reference panel which is placed near an object, an image of which is to be captured along with the object; and a calibration parameter calculator which calculates a coordinate transformation parameter from a coordinate system centered on the image-capturing device to a predetermined global coordinate system, wherein the reference panel comprises: a plurality of light-emitting markers provided at different positions on the reference panel, each of which can assume two states including a bright state and a dark state; and a controller which switches states of the light-emitting markers in accordance with switching patterns which differ from each other and synchronously with switching of frames during consecutive image-capturing operations by the image-capturing device, and the calibration parameter calculator comprises: a marker-identifying unit which specifies a point corresponding to each light-emitting marker in a frame image on the basis of frame images obtained by consecutive capture, by the image-capturing device, of images of the reference panel from a same viewpoint, and which, for each specified point, matches a changing pattern of brightness and darkness of the specified point between the frame images and a switching pattern of states for each light-emitting marker, to thereby identify to which light-emitting marker the specified point corresponds; a parameter calculator which calculates the coordinate transformation parameter from the coordinate system centered on the image-capturing device to the predetermined global coordinate system on the basis of each light-emitting marker of the frame image identified by the marker-identifying unit; a three-dimensional calculator which determines, on the basis of an image captured by the image-capturing device, a three-dimensional coordinate of each point in the image in the coordinate system centered on the image-capturing device; and a light projector which projects coding light for active-type shape measurement, wherein the parameter calculator determines a three-dimensional coordinate of each light-emitting marker in the frame image in the coordinate system centered on the image-capturing device on the basis of a calculation result of the three-dimensional calculator, and calculates the coordinate transformation parameter on the basis of the three-dimensional coordinate of each light-emitting marker in the coordinate system centered on the image-capturing device and a known three-dimensional coordinate of each light-emitting marker in the global coordinate system; the light projector and the light-emitting markers are set so that at least a portion of light-emitting wavelength ranges do not overlap; the calibration parameter calculator determines, from each frame image consecutively captured by the image-capturing device, an image of a wavelength range which falls within the light-emitting wavelength range of the light-emitting marker and which does not overlap the light-emitting wavelength range of the light projector, and calculates a camera calibration parameter on the basis of the determined images, and the three-dimensional calculator determines, from each frame image consecutively captured by the image-capturing device, an image of a wavelength range which falls within the light-emitting wavelength range of the light projector and which does not overlap the light-emitting wavelength range of the light-emitting marker, and determines the three-dimensional coordinate of each point in the image in the coordinate system centered on the image-capturing device on the basis of the determined images.