On the measurement of image disturbance in aerial photography

Abstract

Image quality together with the correction of distortion is very important for airborne photographs used in photogrammetry. Progress in the optical design as well as in production technology and film resolution improved the storage capacity of information to 5 x 10 8 pixels in the image. Distortion can be corrected to be in the region of one micrometer eventhough it needs only to be known in order to be corrected using image processing. Flight conditions usually cause disturbance of image quality. The optical transfer function (OTF) and especially the modulation transfer function (MTF) are useful techniques for measuring the image quality of photographs. The MTF of the image forming system is the result of the contributions of the links in the image transfer forming chain, namely, the camera, the film, image motion (in systems without forward motion compensation, FMC), vibrations, and the atmosphere. For the analysis of the image forming systems, artificial or natural edges are imaged the edge gradient analysis (EGA) and varying spatial requency patterns are used for the grating pattern technique. The aim of this paper is to analyse the influence of image motion, vibration and the atmosphere on the image quality. Results are shown and discussed.