Indexed by: Journal paper

First Author: Yunting Li

Correspondence Author: ZHANG JUN

Co-author: Wenwen Hu,LIU XIAO MAO,Jinwen Tian

Journal: Journal of Optical Society of America A: Optics Image Science and Vision

Included Journals: SCI

Discipline: Engineering

First-Level Discipline: Other specialties in Optical Engineering

Document Type: J

Volume: 32

Issue: 1

Page Number: 156-163

Key Words: Cameras; Machine Vision; Optics; Algorithms; Calibration.

DOI number: 10.1364/JOSAA.32.000156

Date of Publication: 2015-01-07

Abstract: The pan-tilt (PT) camera is widely used in video surveillance systems due to its rotatable property and low cost. The rough output of a PT camera may not satisfy the demand of practical applications; hence an accurate calibration method of a PT camera is desired. However, high-precision camera calibration methods usually require sufficient control points not guaranteed in some practical cases of a PT camera. In this paper, we present a novel method to online calibrate the rotation angles of a PT camera by using only one control point. This is achieved by assuming that the intrinsic parameters and position of the camera are known in advance. More specifically, we first build a nonlinear PT camera model with respect to two parameters Pan and Tilt. We then convert the nonlinear model into a linear model according to sine and cosine of Tilt, where each element in the augmented coefficient matrix is a function of the single variable Pan. A closed-form solution of Pan and Tilt can then be derived by solving a quadratic equation of tangent of Pan. Our method is noniterative and does not need features matching; thus its time efficiency is better. We evaluate our calibration method on various synthetic and real data. The quantitative results demonstrate that the proposed method outperforms other state-of-the-art methods if the intrinsic parameters and position of the camera are known in advance.