COLOR COMPOSITE GENERATION OF THE DMC

摘要

This paper describes the aspects of data processing for the color composite of the Digital Modular Camera (DMC). The DMC is the new digital aerial camera system of Z/I Imaging. With this system the last lack of the digital aerial photogrammetry chain is closed. The key issue of the whole photogrammetric workflow is the geometric image accuracy, which is mostly defined by the camera sensor itself. In order to fulfil the high requirements of mapping applications, 7A Imaging has decided to base the new DMC on a CCD-matrix sensor, because of its stable geometry and its ability of forward motion compensation. According to its modular design, more than one individual camera module can be tied together, resulting in a large field of view of the camera. The full equipped configuration of the DMC is composed of four panchromatic and up to four multi-spectral modules. A post-processing procedure ("mosaicing") serves to transform the four panchromatic images into one virtual image. The color imagery has the same ground coverage as the panchromatic one but only the sixteenth part of the number of pixels. The aim was to generate a color image with the geometrical accuracy of the mosaic image, i.e. a color composite. Therefore the DMC post-processing software fuses the color information of the 3 multi-spectral images with the luminance data of the mosaic. This paper describes the used workflow, the preliminary investigations about several color spaces and their results to select the best practice.