ABSTRACT
Color images code color information according to three channels, corresponding to the red, green, and blue (RGB) components of the image acquisition device. In recent years, the field of digital imaging has extended the traditional trichromatic RGB paradigm to more than three dimensions, introducing what is called spectral or multispectral imaging. The aim of multispectral imaging is to acquire, to process, to reproduce, and to store images with a higher color quality; indeed it is oriented towards those application sectors that request high-quality treatment of color information. Many experiences exist on the successful application of spectral imaging to cultural heritage, this being a field where the acquisition and reproduction of accurate color information are two fundamental processes. Two different approaches exist for multispectral imaging, called respectively narrow-band and wideband image capture. Despite the possibility of estimating reflectance on the basis of smoothing constraints, multispectral imaging systems often rely on training sets.
