Radiometric Information from Airborne Laser Scanning for Archaeological Prospection

Abstract

Airborne laser scanning (ALS) is widely used for the sampling of large landscapes for different application areas. Since several years ALS data is also often used in archaeological prospection, e.g. in order to detect archaeological features beneath the vegetation canopy cover. For most of the applications only the geometric information provided by ALS is utilized. However, next to geometric information ALS provides radiometric information for each acquired point. For its practical usability radiometric calibration is essential. This contribution presents, next to the basic theory, a radiometric calibration workflow for ALS data. As a result calibrated spectral information is added to the ALS point cloud. This information can be used to generate images displaying reflectance at the wavelength of the ALS sensor. The presented calibration workflow is furthermore applied to different ALS missions carried out in the study area Carnuntum, Austria. Due to the usage of ALS sensors with different laser wavelengths, next to single wavelength ALS data, multi-wavelength reflectance data is presented and compared. Additionally, the multi-temporal characteristics of reflectance data are discussed briefly. Finally, the paper is summarized and an outlook into future research work is presented.