# Equivalence of Two Expressions of Principal Line

arXiv: https://arxiv.org/abs/2301.03039 · HTML: https://mlsanity.com/paper/2301.03039/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Builds on 1 of its 8 references that are in the map.
- First posted on arXiv 8 Jan 2023.

## Builds on (most cited first, 1 of 1)

- [A New Technique of Camera Calibration: A Geometric Approach Based on Principal Lines](https://mlsanity.com/paper/1908.06539/) (2019)

## Abstract (arXiv)

Geometry-based camera calibration using principal line is more precise and robust than calibration using optimization approaches; therefore, several researches try to re-derive the principal line from different views of 2D projective geometry to increase alternatives of the calibration process. In this report, algebraical equivalence of two expressions of principal line, one derived w.r.t homography and the other using for two sets of orthogonal vanishing points, is proved. Moreover, the extension of the second expression to incorporate infinite vanishing point is carried out with simple mathematics.