A New Technique of Camera Calibration: A Geometric Approach Based on Principal Lines

TL;DR

This paper introduces a geometry-based camera calibration method using principal lines, improving robustness and flexibility over Zhang's method by providing clear guidelines and accommodating variable focal lengths.

Contribution

A novel calibration technique based on principal lines that simplifies computations and addresses key limitations of existing methods.

Findings

Outperforms Zhang's method in accuracy and robustness.

Provides intuitive guidelines to avoid outliers.

Handles variable camera focal lengths effectively.

Abstract

Camera calibration is a crucial prerequisite in many applications of computer vision. In this paper, a new, geometry-based camera calibration technique is proposed, which resolves two main issues associated with the widely used Zhang's method: (i) the lack of guidelines to avoid outliers in the computation and (ii) the assumption of fixed camera focal length. The proposed approach is based on the closed-form solution of principal lines (PLs), with their intersection being the principal point while each PL can concisely represent relative orientation/position (up to one degree of freedom for both) between a special pair of coordinate systems of image plane and calibration pattern. With such analytically tractable image features, computations associated with the calibration are greatly simplified, while the guidelines in (i) can be established intuitively. Experimental results for synthetic and real data show that the proposed approach does compare favorably with Zhang's method, in terms of correctness, robustness, and flexibility, and addresses issues (i) and (ii) satisfactorily.