Geometric multispectral camera calibration

Abstract

A large number of multispectral cameras uses optical bandpass filters to divide the electromagnetic spectrum into passbands. If the filters are placed between the sensor and the lens, the different thicknesses, refraction indices and tilt angles of the filters cause image distortions, which are different for each spectral passband. On the other hand, the lens also causes distortions which are critical in machine vision tasks. In this paper, we propose a method to calibrate the multispectral camera geometrically to remove all kinds of geometric distortions. To this end, the combination of the camera with each of the bandpass filters is considered as single camera system. The systems are then calibrated by estimation of the intrinsic and extrinsic camera parameters and geometrically merged via a homography. The experimental results show that our algorithm can be used to compensate for the geometric distortions of the lens and the optical bandpass filters simultaneously. © 2009 Springer Berlin Heidelberg.