Automatic multispectral ultraviolet, visible and near-infraredcapturing system for the study of artwork

摘要

This paper shows the simulations of the usage of a LED cluster as the illumination source for a multispectral imaging system covering the range of wavelengths from 350 to 1650 nm. The system can be described as being composed of two modules determined by the spectral range of the imaging sensors responses, one of them covering the range from 350- 950nm (CCD camera) and the other one covering the wavelengths from 900-1650nm (InGaAs camera). A well known method of reflectance estimation, the pseudo-inverse method, jointly with the experimentally measured data of the spectral responses of the cameras and the spectral emission of the LED elements are used for the simulations. The performance of the system for spectral estimation under ideal conditions and realistic noise influence is evaluated through different spectral and colorimetric metrics like the GFC, RMS error and CIEDE2000 color difference formula. The results show that is expectable a rather good performance of the real setup. However, they also reveal a difference in the performances of the modules. The second module has poorer performance due to the less narrow spectral emission and less number of LED elements that covers the near-infrared spectral range.