ABSTRACT: A method of geometric calibration of charge-coupled device (CCD)
vision systems for metric measurement has been developed. The method does not
require a special calibration facility or accurately surveyed three-dimensional (3D)
control points. It only requires that one stereo pair of images of a planar object be
acquired with the CCO camera that is to be calibrated. Using a planar wall constraint as a control, the study identified that a priori knowledge ofseven parameters
of interior orientation could be used to effectively model the interior geometry of
known focal length CCO cameras equipped with zoom lenses. Brick walls provided
an excellent calibration source of such a calibration facility, because they can provide a sufficiently large number of well-defined points throughout the stereo images
at almost any focal setting. The comers of the bricks and mortar joints might be
used as target points. Comparison with laboratory calibration using a 3D test field
showed that the method of planar constraint was capable of providing results of
comparable accuracy at 10-32 mm variable focal settings lens, and potentially even
better results at larger focal settings. A root-mean square (RMS) error of better
than :!:0.2 pixels was achieved consistently for higher values of focal setting. Using
about 40-50 stereo image points, the interior geometry of the CCO camem was
effectively modeled. Increasing the number of image points increased the stability
of the calibration parameters. The method has the potential to be advantageous in
terms of practicality, availability and economy; time saving, and providing a large
number of image points.
تاريخ النشر
04/07/1994
الناشر
Close-Range Techniques and Machine Vision Symposium, Proceedings of the ISPRS Commission V Intercongress Symposium
معالي الأستاذ الدكتور محمد طالب عبيدات | HE PROF. Moh’d Taleb Obaidat | 7208