Comparing two new camera calibration methods with traditional pinhole calibrations.

Two novel camera calibration methods are compared with traditional pinhole calibration: one new method uses an analytic geometrical version of Snell's law (denoted as the Snell model); the other uses 6x6 matrix-based paraxial ray-tracing (referred to as the paraxial model). Pinhole model uses a perspective projection approximation to give a single lumped result for the multiple optical elements in a camera system. It is mathematically simple, but suffers from accuracy limitations since it does not consider the lens system. The Snell model is mathematically the most complex but potentially has the highest levels of accuracy for the widest range of conditions. The paraxial model has the merit of offering analytical equations for calibration.