Spectral Characterization of a Digital Still Camera's NIR Modification to Enhance Archaeological Observation

Scholars using still cameras to take (mostly) oblique imagery from a low-flying aircraft of various possible archaeologically related anomalies can be defined as aerial archaeologists. At present, as well as in the past, aerial/air archaeology has been acquiring data almost exclusively in the visible range of the electromagnetic spectrum. This phenomenon can largely be attributed to the critical imaging process and sometimes unconvincing results related to the film-based approach of near-infrared (NIR) photography. To overcome the constraints of detecting and interpreting only the varying visible colors in vegetation (the so-called crop marks), while still maintaining the flexible and low-cost approach characteristic for aerial archaeology, a consumer digital still camera was modified to capture NIR radiation. By its spectral characterization, more insight was gained into its imaging properties and necessary guidelines for data processing, and future improvements could be formulated, all in an attempt to better capture the archaeologically induced anomalous growth stresses in crops.