The 3D survey of the Mausoleum of Romulus, along the Via Appia Antica, 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 first 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 significant 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.
The Mausoleum of Romulus is one of the greatest funeral monument of the late Roman Empire. The complex was built in the 4th century A.D. for Marcus Aurelius Romulus (292/295-309 A.D), the son of the Emperor Marcus Aurelius Valerius Maxentius. The tomb and the rectangular temenos were enclosed by an impressive quadriporticus of 99.5 by 85 meter, supported by 48 rectangular pillars and covered by cross vaults. Nowadays only the perimetral wall in opus vittatum and some pillars in opus latericium (in the south-est side of the complex) are well preserved and allow the original shape of the portico to be reconstructed. It had two gates: the former oriented towards the Via Appia, the latter, in back of the tomb, connected the temenos with the Maxentian imperial palace built on the hill behind. In the middle of the rectangular portico, the majestic remains of the tomb are still visible. The building was re-used during the medieval age and in the 18th century, was partially incorporated into a farmhouse belonged to Torlonia family. These events allowed the preservation of the semi-subterranean floor of the tomb. The building as it is in the modern state, is composed by a cylindrical rotunda connected to a rectangular body.