Steerable filtering in interactive tracing of archaeological linear features using digital true colour aerial images.

In this study, a semi-automatic approach to support archaeological line tracing is proposed. The suggested procedure is based on colour and texture information derived from orthorectified RGB digital aerial data and consists of four steps: (1) line sketching; (2) steerable filtering; (3) objects selection; and (4) straight line fitting and vectorisation. Good results were observed by evaluating the algorithm according to trace visibility and integrity, global difficulty and level of feature extraction. Further reliability tests were performed to study poor data initialisation and different annual seasonal land use at the same site.