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

NEW PERSPECTIVES OF POINT CLOUDS COLOR MANAGEMENT – THE DEVELOPMENT OF TOOL IN MATLAB FOR APPLICATIONS IN CULTURAL HERITAGE

The paper describes a method for Point Clouds Color management and Integration obtained from Terrestrial Laser Scanner (TLS) and Image Based (IB) survey techniques. Especially in the Cultural Heritage (CH) environment, methods and techniques to improve the color quality of Point Clouds have a key role because a homogenous texture brings to a more accurate reconstruction of the investigated object and to a more pleasant perception of the color object as well. A color management method for point clouds can be useful in case of single data set acquired by TLS or IB technique as well as in case of chromatic heterogeneity resulting by merging different datasets. The latter condition can occur when the scans are acquired in different moments of the same day or when scans of the same object are performed in a period of weeks or months, and consequently with a different environment/lighting condition. In this paper, a procedure to balance the point cloud color in order to uniform the different data sets, to improve the chromatic quality and to highlight further details will be presented and discussed