High-Resolution Photogrammetric Survey of a Romanesque Mosaic Floor: A Comparative Analysis of UAS and a Custom-Built Acquisition System

The high-resolution survey of flat surfaces of significant historical and artistic value, such as decorated floors and mosaics, is a fundamental phase both for the documentation and the preservation of cultural heritage. Given the material and chromatic complexity of these objects, it is essential to obtain photogrammetric data that are accurate from both a geometric and radiometric point of view. This study compares two approaches to this task, both involving a typical photogrammetric workflow, but from two different point of view: firstly, an acquisition using a Unmanned Aerial System (UAS), and secondly, an acquisition very close to the object using a camera mounted on a prototype for mobile photographic acquisitions. This prototype is under development and already tested by the authors, which uses crosspolarisation with a camera and lighting integrated in an enclosed environment into a mobile cart. The aim is to evaluate and compare the effectiveness of two systems in terms of i) speed of acquisition, ii) ease of use, iii) metric quality, iv) level of detail, v) presence of reflections and vi) surface documentation capability.