Effective 3D modeling of heritage sites

Over the past few years, a remarkable increase has occurred in the demand for 3D models for cultural heritage applications. The techniques employed have evolved from surveying and CAD tools and/or traditional photogrammetry into laser scanning and more automated image-based techniques. However, selecting the most effective technique for a given project is not always obvious. We will discuss each technique and point out its advantages and disadvantages. We will then present our approach, which is an integration of several technologies and is based on the experience we gained over more than a decade for accurately and completely model heritage monuments and sites. It was clear from our experience that using a single technique is not an effective approach. A highly detailed structure or site is best modelled at various levels of detail. Image-based modelling is used for the basic shape and structural elements, and high-precision laser scanning for fine details and sculpted surfaces. To present the site in its proper context, image-based rendering or panorama is used for landscapes and surroundings. We demonstrate our approach on two typical heritage sites in Italy: the Abbey of Pomposa near Ferrara and the Scrovegni Chapel in Padova.