Crop marks detection through optical and multispectral imagery acquired by UAV

The discovery of buried remains by means of aerial photography is very useful in archaeological studies. The paper illustrates a two-year project in which an archaeological site near Pavia, Northern Italy, was surveyed several times by an Unmanned Aerial Vehicle (UAV, or drone), equipped with optical and multispectral cameras. Intensity and color orthophotos were produced as well as the NDVI (Normalized Difference Vegetation Index) images. Several very clear and detailed crop marks have been observed whose detection has been performed by visual inspection and by a semi-automatic segmentation procedure. The project confirms the value of drones in terms of operational flexibility and capability of acquiring images having high detail and quality.