Historical aerial photography is routinely used in support of environmental cleanup operations at many Department of Defense sites. The broader use of current best practices for image interpretation and the application of digital image processing techniques can improve the amount of information extracted from the photos. This appears to be important at large formerly used defense sites (FUDS) that were used as practice and demolition bombing ranges (DBR) for bombardier training crews during World War II. The accurate mapping of range features and the identification of sites where demolition ordnance was used is critical to the cost-effective environmental cleanup and transfer of these properties to other public and private uses.
The objective of this project was to demonstrate techniques to make more effective use of historical photography for environmental cleanup support.
Eight study sites located in the southwestern United States were selected for the demonstration project. Six of the sites were located in New Mexico, and two sites were located in Texas. The sites provided a wide range of sizes, ranging from 1 to 774 square miles.
A comparative analysis of three interpretation methods was undertaken. The baseline method relied onexisting results from photo interpretations used to develop Archive Search Reports (ASR) for Military Munitions Response Program sites. These interpretations were based on photographic prints and pocket stereoscopes. The second method was based on film diapositives (positive transparencies) and zoom stereoscopes. The third method was based on scanned film that was digitally processed and viewed. Both alternative methods improved upon the baseline method, with the digital processing approach systematically providing the best results. It was observed by the image analysts that routine image enhancement techniques may provide results similar to the more advanced image restoration techniques tested.
Aerial photography archives are dynamic. Collections continue to expand, and they are becoming more organized and accessible. ASR photo search results should be used as a starting point for subsequent site investigations and remedial efforts, but the photo searches sometimes need to be updated. Acquiring historical photography during or shortly after range operational periods can be critical to the accurate detection and mapping of range features.
The benefits of improved processing, analysis, and use of historical photography are potentially significant. Ongoing work has identified significant errors in existing FUDS locations that can be resolved through the more systematic use of current best practices as well as the new techniques demonstrated in this project.