Remote SWIR (1000-2500 nm) hyperspectral imaging

Reflectance spectral imaging is an efficient way of collecting millions of reflectance spectra over an area in one image cube (2D spatial and wavelength in the 3rd dimension). Remote Short wave Infrared (SWIR, i.e. 1000-2500nm) reflectance hyperspectral imaging can operate at large distances (tens of metres) at submm spatial resolution and high spectral resolution from one position on the ground regardless of the height of the monument/object. The remote SWIR reflectance hyperspectral imaging extends the remote VIS/NIR reflectance hyperspectral imaging in the wavelength range to 2500nm covering the SWIR range of 1000-2500nm. It can give images through any of the combination of spectral channels and more importantly will reveal areas of different material composition through their reflectance spectra. It can complement material identification (both original and degraded material) with VIS/NIR reflectance spectral imaging, remote Raman spectroscopy and if appropriate remote LIBS spectroscopy. The images can also reveal faded drawings, writings and preparatory sketches, as well as areas of degradation and past intervention. The SWIR range by virtue of the longer wavelength can penetrate more easily through materials that is opaque to VIS/NIR light giving better images of preparatory sketches. It is the spectral range that registers the overtones of vibrational modes of molecules making it sensitive to organic and synthetic materials as well as providing more definitive identification for some inorganic materials.