Active camera calibration using pan, tilt and roll

Three dimensional vision applications, such as robot vision, require modelling of the relationship between the 2D images and the 3D world. Camera calibration is a process which accurately models this relationship. The calibration procedure determines the geometric parameters of the camera, such as focal length and center of the image. Most of the existing calibration techniques use predefined patterns and a static camera. Recently, A. Basu (1993) developed a novel calibration technique for computing the focal length and image center which uses an active camera. This technique does not require any predefined patterns or point to point correspondence between images-only a set of scenes with some stable edges. It was observed that the algorithms developed for image center are sensitive to noise and hence unreliable in real situations. The article extends the techniques provided by Basu to develop a simpler, yet more robust method for computing the image center.