Tecniche di rilievo 3D per lo studio e la catalogazione del patrimonio religioso di Napoli: la chiesa di San Nicola dei Caserti

The study of ecclesiastical patrimony of Naples aimed at knowledge, cataloguing and offered ideas of research and experimentation, the complexity of layers, overlap with the new urban fabric and the wealth of decorative elements, require a thorough documentation in terms of shape, color, geometry and tructural-historical features for which it was essential the use of three-dimensional data acquisition systems , no contact based on light radiation. Particular attention was paid to the importance of religious heritage not usable in Naples, concrete example of great historical and architectural interest, conducted with laser scanner with integrated photogrammetric survey that has enabled us to provide extremely quickly and with high accuracy all the information and metrics qualitative for the subsequent operations of cataloging, preservation and use. It describes the case of example of the Church of s. Nicola dei Caserti in the road before that of Don Pietro, today San Nicola dei Caserti, which connects via dei Tribunali to the Vicaria Vecchia; This is a church closed to the public, a total State of disrepair and decay and completely stripped of all good and sacred furnishings. Currently the outside Church, the still shows clear signs of the bombing and subsequent recovery operations the unit wall, with a few original elements, within the original structure, a Greek cross with side chapels, the roofing system is featured in succession by a barrel vault with lunettes, an elliptical dome and a barrel vault to the aisle , a fairing on the main altar and apse interspersed with round arches, while the side chapels, are characterized by a barrel vault roof. The interior decoration with Corinthian columns and entablature, is very rich and almost completely preserved but with multiple injuries and aggression by pathogens and humidity, altars only the perimeter walls. The survey was performed with a laser scanner Faro Focus. This sensor has a measurement range of the nominal distance between 60 cm and 120 meters, with an accuracy in the measurement of the distance of the order of ± 2mm to 25 meters and an angular resolution equal to 0.009°. It performs the measurement by analyzing the phase of the signal. The vertical field of view is equal to 305°, the horizontal field of view is 360 ° and the acquisition speed of the points is equal to 976,000 points/sec. While scanning the laser rotates around a vertical axis 360° while the mirror directs the beam vertically. The distance, the vertical angle and the horizontal angle generates a polar coordinate, which is then converted into a Cartesian coordinate (x, y, z). Equipped with an integrated digital camera with coaxial optical axis measuring radius of laser, which allows you to capture the information of each point colorimetric acquired. The instrument uses a removable memory for storage of the measured data, the scan parameters can be adjusted via a touch screen display integrated into the instrument, this allows you to work with the tool even without the aid of a computer, although you can through the supplied software, Faro Scene, create configuration files on PC to transfer to the SD and then load them from the scanner. Another interesting feature is the possibility of a connection with other wireless devices that makes the tool manageable distance. Compared to other types of scanner It is a particularly light and compact equipment, 5.2 Kg to 240 x 200 x 100 mm which enables a fast employment in the field requiring for a photographic tripod rather than one topography; also has a compass, a height sensor and a Compensator that facilitates placement. It is equipped with batteries with a range of about 4.5 hours and the laser beam is class 3. The experience led the Church of San Nicola dei Caserti has made it possible to highlight a number of benefits and potential of laser scanning survey such as the ability to obtain accurate, authentic and the global factory in extremely small, get a pad that allows readings resulting from different approaches, from the historic to the architect and archaeologist Restorer with its need for reading the artifact and to assess and analyze elements with character of originality than those of recent execution, stratifications that have largely characterized the factory, the analysis of the degradation and problems accurately and punctually. Laser relief also constitutes an archive template that uncritically “photographer” the condition of the artifact at a time when it is detected. Another important aspect is represented by the possibility to take advantage of data acquired for the creation of a virtual reconstruction of the Church in its original configuration.