Different photogrammetric approaches to 3D survey of the Mausoleum of Romulus in Rome. A.Adami 1 , I. Cerato 1 , E. d’Annibale 1 , E. Demetrescu 1 , D. Ferdani 1 1 CNR –ITABC, Montelibretti, Rome, ITALY Abstract In recent years, digital photogrammetry has enjoyed a renewed approval in the ield of Cultural Heritage. This is due both to the relative cheapness of the instruments (a high resolution camera, possibly a relex with good lenses) and to new algorithms and software that simpliied the use, perhaps at the expense of the necessary knowledge of its principles. The 3D survey of the Mausoleum of Romulus, along the Via Appia Antica, within the European project 3DICONS, provided the opportunity to test different photogrammetric techniques, with the aim to verify the results and to evaluate the positive and negative aspects. In particular two different approaches have been applied: spherical photogrammetry and dense image matching. The irst technique is based on traditional photogrammetric principles, applied on panoramic images instead of frame images. The second one, the most recent and very widespread, is inspired by traditional photogrammetry and computer vision. In order to have a signiicant and correct comparison, a topographic support has been realized for the Mausoleum, to have all surveyed data in a single local reference system. The comparison has been made by using, as a reference, the point cloud acquired by laser scanner. In this paper, after a description of the funeral monument and its complexity, the two techniques will be described in order to investigate pros and cons, their algorithm and application ields. The acquisition and processing stage will be described in order to give all the necessary elements for the inal judgement. At the end of the restitution and modelling process, the comparison will take into account many parameters: the scheme of image acquisition, the time required (on-site and in laboratory), the hardware (for data acquisition and post-processing), the results that can be obtained (2d and 3D representations with texture) and the metric accuracy achieved. Finally there will be some hints about different applications of these methods as concerning above all the visualization of data. For example, the exploration of the Mausoleum can be done through the navigation of bubbles, obtained by spherical photogrammetry. Categories and Subject Descriptors: [Applied computing]: Arts and humanities, Architecture; [Computing methodologies]: Computer Vision: Image and video acquisition, 3D imaging; [Computing methodologies]: Computer Graphics: shape modelling, mesh models. 1. Introduction In the field of survey and digitization of Cultural Heritage (CH) photogrammetry and laser scanner play a very important role [Bal99] [Boe06]. When laser scanner has started to be used in CH, photogrammetry seemed to have lost its reference role. The ease of measure, the large num of acquired information and the development of user- friendly software and hardware seemed to attribute to laser scanner technique the role of leader for the 3D digitization in CH [BM04]. In recent years, however, thanks to software developments, photogrammetry has returned to be very competitive. Some of its difficulties that characterized the classic photogrammetric survey, have been supplanted in favour of a simpler approach. It is no longer a task suited only for skilled operators. There is no longer need of large investments in software and equipment (metric or semi-metric digital camera) and is no longer a long time consuming technique. The introduction and development of high-resolution digital camera has certainly contributed to this renewed success. But the main push probably has come from the field of computer vision, where the goal was to reconstruct three-dimensional objects and environments c  The Eurographics Association 2014. EUROGRAPHICS Workshop on Graphics and Cultural Heritage (2014) R. Klein and P. Santos (Editors) DOI: 10.2312/gch.20141300