Calibration of a moving zoom-lens camera for Augmented Reality applications

In Augmented Reality systems, real time integrating 3D virtual objects into the real environment requires camera calibration techniques for spatial alignement. The accuracy of the parameters is then a crutial task for designing an effective Augmented Reality (AR) systems, and the challenge to meet this requirement is made harder when dealing with moving zoom-lens cameras. Although recent approaches have been proposed using 2D/3D patterns, the use of zooming lens cameras brings new problems for robust and continuous estimation of the intrinsic parameters. This paper propose a robust algorithm for variable focal length calibration combining interferometry and 2D pattern detection to tackle the problem. A global optimization routine is driven to search for the best calibration parameters that fit the system. After a description of the different methods involved in each step of the process, the approach is validated with AR experimental results on a real time AR touristic application.