Heritage site preservation with combined radiometric and geometric analysis of TLS data

- A damage mapping methodology based on TLS data is applied in heritage assets.
- The approach analyses both geometric and radiometric data recorder by TLS.
- Radiometric analyses allow the detection of chemical and biological damages.
- Geometric analyses allow the detection of physical damages.
- The success of the radiometric analyses are based on the calibration of the TLS.

Damage mapping is considered a critical stage in the correct diagnosis of the state of conservation of Cultural Heritage manifestations. The common approach generally implies a large user interaction to map the different pathological processes presented on 2D documents such as elevations or sections, among others. In contrast with this practice, the present paper proposes a semiautomatic 3D-methodology, with a minimum user interaction, able to accurately analyse both radiometric and geometric data recovered by a non-contact technology (Terrestrial Laser Scanning), allowing the extraction and quantification of a wide diversity of pathological processes from biological colonization to deformations. This approach is therefore a potential tool for the rapid and accurate diagnosis of Cultural Heritage. To confirm the applicability and potential offered by the proposed methodology, a highly affected historical masonry, the San Francisco Master Gate of the Almeida Fortress (Portugal), was evaluated by using the Faro Focus 3D 120 Laser Scanner.