<title>Calibration of CCD cameras for field and frame capture modes</title>

Abstract

Small format, medium resolution CCD cameras are at present widely used for industrial metrology applications because they are readily available and relatively inexpensive. The calibration of CCD cameras is necessary in order to characterize the geometry of the sensors and lenses. In cases where a static or slowly moving object is to be imaged, frame capture mode is most often used to maximize the resolution of the CCD sensor. In cases where the object to be imaged is in rapid motion, field mode capture is frequently adopted to avoid discontinuities caused by the interlaced scanning process used by the sensors. A strategy for the computation of calibration parameters for field modes, based on a frame mode calibration, is proposed. The strategy is then verified by testing using real data from test range calibrations of three different types of CCD camera. The results of these calibration tests are described, with particular emphasis on the changes required to adjust between frame and field capture modes.