Deriving relief of a coastal landscape with aerial video data

Coastal geomorphological research benefits from visualization of heights. Videography, a cheap, simple and flexible airborne remote sensing technique, was used for derivation of relief. A hand-held Hi 8 camera and a small aeroplane were used to collect video data of a 1300 m x 320 m strip of beach and foredune area on Ameland (the Netherlands). Simultaneously, the ground control points (GCPs) were measured with laser electronic distance measurement (EDM) equipment. A series of overlapping frames was grabbed, contrast-stretched and corrected for interlacing effects. The resulting images were processed with software that has some photogrammetric capabilities, R-WEL's Desktop Mapping System (DMS). The images and the positions of the GCPs enabled computation of the camera orientation, and allowed for image rectification and stereo correlation. Stereo pairs form the basis for anaglyphs, which give a perception of height. In addition, the parallax in the stereo pairs allows a derivation of quantitative height information. Some of the derived height values are, however, incorrect. This was due to inaccuracies in the camera technology and the use of photogrammetric software that was not designed principally to process video imagery.