<title>Calibration stability of the Kodak DCS420 and 460 cameras</title>

Portable digital image cameras such as the Kodak DCS420 and 460 are widely used for metric applications of close-range photogrammetry. The use of these cameras is typically in one of two forms, either as a mobile single camera for offline industrial measurement applications, or in a multi-camera system for online operation in a `work-cell' environment. In common with any metric system, the calibration of the cameras is of paramount importance to maintain the fidelity of the collinearity solution, and therefore the maximum possible accuracy. Any variation in the calibration during image capture for an offline or an online system will inevitably have a deleterious effect on the measurement accuracy. This paper describes a series of experiments concerning the calibration stability of DCS420 and 460 cameras in offline and online configurations. The calibration strategy is described and the effect of a minor modification to the CCD sensor mounting is presented. The variations in RMS image residuals and calibration parameters are quantified in terms of magnitude and significance for the different modes of operation.