Low Cost Technique for Accurate Geometric Documentation of Complex Monuments by Non-experts

This paper proposes the technique of stereo-orthoimage for reliable and accurate identification and digitization of complex features of cultural heritage (CH) monuments (e.g., edges, outlines, damages, holes, cracks) in the context of large-scale geometric and damage documentation. It is a low cost technique, which can be implemented by non-experts (architects, archaeologists, etc.). A developed plugin, named OrthoSteroMate (OSM), for the open-source GIS system QGIS that implements the stereo-orthoimage technique is presented. It introduces stereo-orthoimages in GIS environments, as complements to conventional orthoimages, allowing better interpretation of the details of built CH and enabling more accurate digitization, taking advantage of stereoscopic observation when no special equipment or photogrammetric knowledge are needed. The application of the plugin along with QGIS tools for the restitution of two CH monuments were made, yielding satisfying results and proving the applicability of the proposed low-cost method for complex CH documentation.