Photogrammetric Approach to Self-calibration Prosess Employing Intrinsic Parameters Variation for Zoom Lenses

Non-metric cameras, which are commonly used in close-range photogrammetry applications, allow the combination of both digital and mechanical zooming satisfactorily. During the zooming process, the optical behaviour of the lenses changes depending on the feature of the used optical system. This modification is accomplished by optimising the number of pixels used on the digital sensor's projection plane. Additionally, high-definition non-metric cameras have a problem that when sharpening the image, deteriorates the definition of the image plane. On the other hand, industrial cameras, which are generally used in close-range photogrammetry and architectural photogrammetry, could tackle this problem by using additional image enhancement instruments. These digital non-metric cameras are calibrated by fixing for maximum and minimum zooming focal length and they are suitable to be used in this range. In this chapter, an Olympus E10 camera was employed in the calibration process to answer the requirement for the modification in different focal lengths. It is deduced that its calibration data, which is obtained in a three-dimensional test field together with the distortions on the object, can be used to detect the optical behavior of zooming objects for mechanic zooming. We can predict the best intrinsic values for the camera, also the zooming behavior of the lenses, before the calibration step.