Using Photogrammetry and Laser Scanning in Surveyng Monumental Heritage: le Grotte di Castellana

Using the most recent survey techniques of an Architectural or Monumental Heritage, this study investigates problems on three-dimensional modelling in order to develop and to promote vision metrology. Treatment of different survey techniques aims at defining, in a systematic way, their own distinct procedures and, meanwhile, investigating numerous uses for various fields of application. It is plain that the achievable accuracy, with specific characteristics of every single technique, determines a considerable variety of attainable products that vary from navigable three-dimensional models for tourist and popular aims to 3D Informative System for Architectural Heritage conservation and restoration. As a first approximation, it is intuitively remarked that Laser Scanning and Metric Cameras Photogrammetric survey products will be addressed to precious Monumental Heritage, in which accurate control operations of spatial information, with perfect metric object knowledge for conservation and restoration, it is necessary. All this is true both for Architectonic manufactures and other artistic and historical works that would be studied and preserved. Recent instruments with minor accuracy achievable (digital cameras, etc.) can certainly be utilized for three-dimensional models, also with 3D Modelling and Virtual Reality techniques, in order to permit public knowledge and fruition of monuments. In this case we want investigate in such situations, and with what accuracy they already are a valid alternative in the field of Monument metric description. In this study we analyse a monumental site, “Le Grotte di Castellana” situated in Castellana (Bari), in the Apulia region. It has been realized a survey campaign with Laser Scan Mensi GS 100, Photogrammetric instrumentation: Nikon D100 reflex digital camera with 6 Mpixel CCD calibrated in our laboratory. We have investigate different methods of camera calibration with commercial softwares (StereoView, Photomodeler, etc) and we have product orthophotos using Digital Surface by Photogrammetric correlation. The survey process had permitted three-dimensional coordinates identification of scattered points. These describe an opportunely treated geometry of surveyed object and consent three-dimensional model realization of its exterior surface. Such spatial informative system model can aid image analysis operations, supporting future Restoration and Conservation projecting decisions.