Combined application of pansharpening and enhancement methods to improve archaeological cropmark visibility and identification in QuickBird imagery: two case studies from Apulia, Southern Italy

Launch of Very High Resolution (VHR) satellite sensors meant a significant evolution for Remote Sensing archaeological applications since data with high spatial resolution may be used to identify signals related to buried archaeological remains (e.g. cropmarks, soilmarks, dampmarks) in very extended territories. The aim of this work is to develop a suitable image processing workflow to improve the cropmark visibility in the VHR satellite images. The workflow implemented consists of two steps: first the panchromatic and multispectral images have been pansharpened in order to merge the two images, then some Enhancement methods have been applied on the pansharpened image. As a result of the several tested pansharpening techniques, the Principal Component Resolution Merge yields images of very good quality useful not only for visualization but also as input for further processing. Among the different enhancement methods taken into consideration, the Spatial Enhancement, carried out by applying the Wallis Adaptive filter further improve the visibility and recognition of the archaeological signals. All methods were evaluated on QuickBird imagery acquired in the Tavoliere plain (Apulia, Southern Italy) on May 27th, 2006. In particular, cropmarks generated by two buried ancient settlements were considered. For one of these test sites, results of a high resolution ground magnetic survey, carried out for other aims, were also employed to further assess the validity of information extracted by the proposed workflow. (C) 2013 Elsevier Ltd. All rights reserved.