Multispectral Sensing and Data Integration for the Study of Heritage Architecture

Recording and processing of terrestrial multispectral information can be of significant value for built heritage studies. The efficient adoption of sensing techniques at the visible, near-infrared, and long-wavelength infrared spectra, and the integrated analyses of the produced data, is essential for the observation of historical architecture; especially for the implementation of non-destructive preliminary surveys, which can provide with a general idea for the state-of-preservation of a structure and indicate areas of interest for more detailed diagnostic procedures. The technological developments regarding high-resolution thermal imaging, near-infrared imaging, terrestrial laser scanning (TLS), and the advances in digital photogrammetry and visual analytics play a great part in this. The presented work focuses on the fusion and the combined analysis of two-dimensional (2D) multispectral results to study architectural heritage. Spectral images-captured with a modified DSLR camera-, thermograms, photogrammetrically produced orthophoto-maps, and spatial raster data produced from TLS point clouds, are fused, and analyzed. The results are evaluated from the scope of mapping surface materials, deterioration patterns, and hidden defects, towards the employment of advanced geomatics approaches to effectively monitor cultural heritage. The described methods and techniques are implemented using as case studies the façades of the Castle of Valentino in Turin, an important architectural monument included in the list of UNESCO World Heritage Sites.