A method for calibrating a camera including (a) obtaining a two-dimensional (2D) homography that maps each of parallelograms projected onto two images taken by the camera into a rectangle, wherein the 2D homography is defined as a rectification homography and wherein new cameras that have virtual images are defined as rectified cameras and a new infinite homography is generated between the two rectified cameras, the virtual images being transformed from original images by the rectification homography; (b) obtaining an original infinite homography by using the correlations among the new infinite homography, the rectification homography and the original infinite homography; and (c) obtaining intrinsic camera parameters based on the correlation between the original infinite homography and the intrinsic camera parameters, thereby calibrating the camera.