Practical pan-tilt-zoom-focus camera calibration for augmented reality

Juhyun Oh, Seungjin Nam, Kwanghoon Sohn

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)


While high-definition cameras with automated zoom lenses are widely used in broadcasting and film productions, there have been no practical calibration methods working without special hardware devices. We propose a practical method to calibrate pan-tilt-zoom-focus cameras, which takes advantages from both pattern-based and rotation-based calibration approaches. It uses patterns whose positions are only roughly known a priori, with several image samples taken at different rotations. The proposed method can find the camera view's translation along the optical axis caused by zoom and focus operations, which has been neglected in most rotation-based algorithms. We also propose a practical focus calibration technique that is applicable even when the image is too defocused for the patterns to be detected. The proposed method is composed of two separate procedures - zoom calibration and focus calibration. Once the calibration is done for all zoom settings with a fixed focus setting, the remaining focus calibration is fully automatic. We show the accuracy of the proposed method by comparing it to the algorithm most widely used in computer vision. The proposed algorithm works also well for real cameras with translation offsets.

Original languageEnglish
Title of host publicationComputer Vision Systems - 7th International Conference, ICVS 2009, Proceedings
Number of pages10
Publication statusPublished - 2009
Event7th International Conference on Computer Vision Systems, ICVS 2009 - Liege, Belgium
Duration: 2009 Oct 132009 Oct 15

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume5815 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other7th International Conference on Computer Vision Systems, ICVS 2009

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Computer Science(all)


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