Novel Concepts for Aerial Digital Cameras
ISPRS Commission I: Sensors, Platforms and Imagery, 2002
Aerial film cameras are highly standardized measuring systems. The race is on to find a digital successor applicable as a photogrammetric measuring device with clear advantages over film, meeting accepted standards, covering a large field-of-view, maximizing the geometric resolution of terrain surface detail, minimizing the number of flight lines. Some of today's digital cameras have a small format at a relatively low resolution for special applications. High expectations are associated with the ADS40 by Leica Geosystems (Leica, 2002) using multiple linear arrays in a push-broom mode in analogy to multi-spectral satellite remote sensing systems. Finally there exists the DMC by Z/I Inc. with multiple square arrays CCDs which are assembled into a large virtual image as explained by Z/I Inc (2002). We argue that these digital camera concepts are not replacing the existing film cameras. They have limitations as photogrammetric measuring sensors and they require a workflow that deviates from the established photogrammetric processes. We argue that the desired digital aerial camera will produce metric imagery as if it had been obtained from a traditional film camera and photogrammetric precision scanner, but at advantageous radiometric performance, advantages in the image acquisition and without the cost of film or film scanning.