3D survey technologies: Investigations on accuracy and usability in archaeology. The case study of the new "Municipio" underground station in Naples

Advanced 3D survey technologies, such as Digital Photogrammetry (imaged based) and Laser Scanner, are nowadays widely used in Cultural Heritage and Archaeological fields. The present paper describes the investigations realized by the Laboratory Hesutech of the Polytechnic of Milan in cooperation with the Superintendence Archaeology Campania in order to examine the potentiality of Image Based Modeling (IBM) systems applied to the archaeological field for advanced documentation purposes. Besides the 3D model production workflow in an uncommon excavation environment, a special consideration about the reached accuracy will be discussed. In the first part of the research, a comparison between photogrammetric camera parameters obtained with IBM systems and the ones provided with the calibration certificate by the manufacturer of the camera is performed. In the second part of the research, the operational phases of the application of such advanced 3D survey technologies are shown. The test field is the archaeological excavation area for the construction of the new "Municipio" underground station in Naples. Due to its position in one of the historical area of the city, its construction coexists with the archaeological excavations and it is strictly tied to their evolution. In such conditions, the need to reduce as much as possible the time to build the public infrastructure is a very relevant feature together with the ability to produce accurate documentation of what is considered archaeologically important.