Calibration of a fish eye lens with field of view larger than 180 ◦

We present a complete step-by-step approach to calibration of ultra wide angle fish-eye lenses with the angle of view larger than 180◦. Such a large field of view is necessary for some applications such as the 360 x 360 mosaicing. Recently, a Nikon FC-E8 fish eye lens converter with the field of view equal 183◦ become available. In this paper, we propose its model, suggest a calibration procedure, and demonstrate its use in a mosaicing application. First of all we propose a general model of a camera with field of view larger than 180◦. Then, we identify the structure and the parameters of the mapping between the incoming light rays and pixels for the Nikon FC-E8 converter. Finally, we present a complete camera calibration method from a known calibration target.