Photogrammetric observation of the variation of intrinsic parameters for zoom lenses

Abstract

Today, non-metric cameras are used wide-spread in close-range photogrammetric applications. Such professional cameras can be combined with both digital and mechanical zooming satisfactorily. Optical behavior of the lenses is changed depending on the feature of the optical system used during the zooming process. This so-called change is arranged by optimizing the number of pixels used on the digital sensor, on the projection plane. The problem of high definition, digital, non-metric professional cameras is that while sharpening the image, it deteriorates the definition of the image plane. Industrial cameras, which are used in industrial production, can overcome this problem by using additional image enhancement instruments. These digital non-metric cameras, which are generally used in close-range photogrammetry and in architectural photogrammetry, are calibrated by fixing for maximum and minimum zooming focal length and they are suitable to be used in this range. In this study, an Olympus E10 camera is calibrated to meet the need for the modification, for different focal lengths. Its calibration data, which is obtained in 3D test field, together with the distortions on the object, is used to detect the optical behavior of zooming object for mechanic zooming. Key words: Camera calibration, zoom lens distortion, close range photogrammetry, parameter estimation, parameter analysis.