Documentation of archaeological excavations is one of the most important tasks in archaeology. Images serve as visual evidence of the condition and relative position of structures, artifacts and other findings within the site. These findings can later be analyzed and further studied. Surface-level photography provides details about the findings. However, to place the findings in the context of their location relative to structures or artifacts, overhead visual information is needed.
The purpose of the Calit2 Archaeology Aerial Photography System (CAAPS) is to provide imagery of archaeological excavations from a low-altitude aerial perspective for digital site mapping and general photography needs. The system will be useful in the creation of an historical visual catalog that documents structures and important findings during the excavation. The system consists of a helium-filled urethane balloon positioned over the excavation. The balloon is tethered to the ground using a high-strength SPECTRA line. Two Canon cameras are suspended from the balloon and remotely triggered via a wireless transmitter. In addition the cameras offer a real- time live feed of the target (LiveView) that aids in the positioning of the balloon over the area.
In addition to providing visual evidence of structures and other archaeological findings by means of digital photography, CAAPS will produce images for the creation of 3D files that will aid in surface analysis of the terrain and structures.
CAAPS Design Parameters
Rapid Deployment: One of the concerns with the utilization of a camera mounting system is the time spent in the deployment and resources needed for collecting visual evidence. CAAPS addresses this concern by allowing the cameras to remain in the air after deployment saving resources and time.
Recoverability/Reusability: The system addresses the recoverability and reusability parameters by allowing the system to be recovered after deployment. The use of a tethered balloon allows the system to be brought down when necessary. A concern about survival of the system in harsh weather conditions is minimized because the balloon is made of urethane and UV protected. (Damage is more common when the system is inflated and on the ground or due to inadequate storage.) When proper care is taken, the balloon is known to still be functional from four to seven years in places like Africa, Australia and other challenging environments. The material can also be patched if punctured, even when inflated. A detailed data sheet is available on request.
Image Quality and Control: CAAPS uses two Canon EOS 50D SLR Digital Cameras with 50mm lenses and an image resolution of 15.1 Megapixels. Images are transmitted to a Toughbook via an onboard wireless transmitter. The Toughbook is furnished with software that allows for remote control of some camera features, including zoom, aperture and shutter speed.
The project is led by UC San Diego aerospace engineering majors David Hernandez and Casey Barrett, under the supervision of Prof. Tom Levy.