Camera calibration device and method, and computer system

A camera calibration device for calibrating a stereo system, which includes a base camera and a detection camera, the device comprising:

• an image holding device for holding images, said images obtained with the base camera and the detection camera at at least three view points free from any spatial positional restriction;
• and
• a parameter calculating device for calculating parameters necessary for distance measurement in the stereo system based on the images held by the image holding part, the parameter calculating device including
• a first part for presuming distortion parameters of the base camera and the detection camera by the use of the shot images,
• a second part for calculating projective transformation matrixes to project the shot images respectively onto predetermined virtual planes,
• a third part for calculating internal parameters of the base camera on the basis of the projective transformation matrixes obtained by the second part with regard to the images from the base camera, wherein said third part calculates said internal parameters of the base camera without camera position information,
• a fourth part for presuming the position of the shot plane based on both the internal parameters of the base camera calculated by the third part and the images obtained from the base camera, and
• a fifth part for calculating projection matrixes for the detection camera based on both parameters of the plane position presumed by the fourth part and the images obtained from the detection camera.