Omnidirectional Camera Model and Epipolar Geometry Estimation 

                 by RANSAC with Bucketing

                    B.Micusik, T.Pajdla
                          
Abstrakt:

We present a robust method of image points sampling used in \R{ransac}
for a class of omnidirectional cameras (view angle above $180^\circ$)
possessing central projection to obtain simultaneous estimation of a
camera model and epipolar geometry. We focus on problem arising in
\R{ransac} based estimation technique for omnidirectional images when
the most of correspondences are established near the center of view
field.  Such correspondences satisfy the camera model for almost any
degree of an image formation non-linearity.  They are often selected
in \R{ransac} as inliers, estimation stops prematurely, the most
informative points near the border of the view field are not used, and
incorrect camera model is estimated. We show that a remedy to this
problem is achieved by not using points near the center of the view
field circle for camera model estimation and controlling the points
sampling in \R{ransac}. The camera model estimation is done from image
correspondences only, without any calibration objects or any
assumption about the scene except for rigidity.  We demonstrate our
method in real experiments with high quality but cheap and widely
available Nikon FC--E8 fish-eye lens.