A Dartmouth-led study has demonstrated how the latest aerial thermal imagery is transforming archaeology due to advancements in technology. Today’s thermal cameras, commercial drones and photogrammetric software has introduced a new realm of possibilities for collecting site data. The findings serve as a manual on how to use aerial thermography.
Archaeologists have long used thermal infrared images to locate buried architecture and other cultural landscape elements. The thermal infrared radiation associated with such archaeological features depends on several variables, including the make-up of the soil, its moisture content and vegetation cover. Past conventional geophysics methods, such as fieldwalking, enabled archaeologists to obtain field data across one hectare of a site per day. But, aerial thermography makes it possible to gather field survey data across a much larger area in much less time.
New Photogrammetric Software
New aerial thermography has other advantages, as well. Older cameras were unable to record full spectrum data or temperature data for every pixel of an image. Today’s radiometric thermal cameras coupled with small inexpensive, easy to fly drones, which can be controlled by a smartphone or tablet.
Researchers made aerial thermography more accurate, comprehensive and accessible. Mapping multiple aerial images together has also become easier through new photogrammetric software. Which automatically aligns images and features ortho-image capabilities, which corrects an image to make the scale uniform.
The researchers conducted case studies at six archaeological sites in North America to assess the effectiveness of aerial thermal surveys. They analyzed weather, environment, time of day, ground cover. And archaeological features may affect the results, and compared their findings to earlier research and historical images.
The discovery enable the site’s optimal conditions, the soil matrix, low density ground cover, and the environmental conditions at the time of the aerial thermography. They were also able to recognize traces of long-removed historic buildings and pathways at the Shaker Village in Enfield, N.H.
More information: [Cambridge Core]