September 2006 | What's the buzz?
Airborne Digital Imagers: An Overview & Analysis
On behalf of BAE Systems, Stewart Walker attended the ISPRS Commission I Symposium, in Paris, France, in early July, and gave a joint paper with Gordon Petrie of the University of Glasgow-a regular contributor to the European journal GeoInformatics. The paper, “Airborne Digital Imagers: An Overview & Analysis” covered hardware, software and industry trends.
It was clear during the Symposium that the airborne digital imagers that have attracted so much attention over the last six years are now fully operational and selling well. There are perhaps 120 systems from the three best known suppliers in use, plus an even larger number of medium-format single- and multiple-camera systems of many different types from numerous suppliers. Experts are reviewing issues such as calibration, triangulation and systematic image distortions, but the critical trend is that we have moved forward from talking about the basics of the new systems to reviewing their performance and potential. The airborne digital imager, sensor or camera, is here to stay.
There is abundant evidence of superb image quality and the capability of the new systems to serve as the basis of workflows leading to timely and compliant deliverables. There is some suggestion that results equivalent to or better than those from scanned film can be obtained even with larger pixel sizes, though not yet enough examples to induce new guidelines or principles. Similarly, it is too early to judge the effect of the new imagery on the success of operations such as image matching. And of course return on investment is a complex, longer-term issue that will become clearer in the months to come.
Immediately after ISPRS Commission I, Walker took part in a meeting of the Geospatial Data Acquisition Technologies in Design and Construction Committee of the Transportation Research Board, held in Port Angeles, WA. The meeting addressed many topics, but the most captivating moments were spent participating in a discussion on the future of the aerial film camera.
The Committee has many members from various Departments of Transportation (DOTs), the State level bodies responsible for highways in the U.S., which have been prime movers in the development of U.S. photogrammetry over the years. Concern was expressed that the days of the aerial film camera are numbered. People are worried, for example, that it will soon become difficult to obtain the cameras themselves, or spare parts, or technicians with the skills to assemble and install them. They are worried that films, chemicals and papers may become unavailable.
The suppliers would say otherwise: film cameras are readily available for purchase, as are spares and supplies. It is true that users of the new digital cameras are allocating as much work as possible to them, so some film cameras are seeing less use than before, but it seems certain that our industry, with its customary ingenuity and search for efficiency, will use film and digital methods in the optimal combination for many years to come. We are in the midst of healthy debate, but the underlying process is evolutionary rather than cataclysmic.