Rapid scanning of aerial film archives with PromptSCAN
From the 1930’s to about the year 2000 most of the world was captured at regular intervals on high resolution aerial film using aerial mapping and reconnaissance cameras, by national mapping organizations, defence organization and private mapping companies. During that time, the Earth has been transformed by massive developments and these changes have been recorded on millions of rolls of aerial film that mostly lie locked away and inaccessible in archives. Unfortunately, due to past technical limitations and laborious manual feature extraction, only a small fraction of the information content in these films was ever been recorded on paper maps and most of these are neither accessible or in digital format. Many of the films are deteriorating, or even worse, are being disposed of due to high storage costs.
GeoDyn’s owner, Rolf Becker, had identified an urgent need to bring these archives into the digital domain and has since focused considerable time and effort to redress this situation. Until recently, the scanning of the films was a very slow and expensive process. Under his direction, GeoDyn is revolutionizing the democratization of this information by the development of PromptSCAN, a highly advanced photogrammetric aerial film scanner capable of transforming these aerial films rapidly into easily accessible, accurate digital images that maintain the full information content, thereby safeguarding and providing a wealth of temporal image information. With a capture rate in excess of 3 seconds per frame, PromptSCAN’s speed of conversion is now some 50x faster and a magnitude cheaper than was previously possible. GeoDyn is well aware that many organisations have their own resources capable of performing the scanning operation using GeoDyn’s technology and this too, can significantly reduce costs.
Analogue to digital conversion of aerial film archives is only the initial step, though an extremely important one. To be able to realise the full potential of temporal aerial photography, GeoDyn also recognises the offer the need to offer services required to transfer the scanned images into image maps that are geo-referenced with detail-matching accuracy for information extraction and analysis in GIS. GeoDyn, in close cooperation with Esri, has developed high performance procedures to accurately geo-reference and serve temporal image maps to multiple applications. The resulting image maps can be served as dynamic image services providing access to the full information content of every image or as temporal tile cache ortho-mosaics providing fast visualization for the end user.