This paper presents a solution to the problem of pose estimation
in the presence of heavy radial distortion and a potentially
large number of outliers. The main contribution is
an algorithm that solves for radial distortion, focal length
and camera pose using a minimal set of four point correspondences
between 3D world points and image points. We
use a RANSAC loop to find a set of inliers and an initial estimate
for bundle adjustment. Unlike previous approaches
where one starts out by assuming a linear projection model,
our minimal solver allows us to handle large radial distortions
already at the RANSAC stage. We demonstrate that
with the inclusion of radial distortion in an early stage of
the process, a broader variety of cameras can be handled
than was previously possible. In the experiments, no calibration
whatsoever is applied to the camera. Instead we assume
square pixels, zero skew and centered principal point.
Although these assumptions are not strictly true, we...