Hyperspectral VIS/SWIR wide-field imaging for ink analysis
Vincent Cardin, Laura‐Isabelle Dion‐Bertrand, Frédérick Poirier, S. Marcet, Jacob Yvon-Leroux · 2020
Hyperspectral imaging can reveal the slightest difference in the spectral response of seemingly identical inks. We have studied the reflectivity of the fundamental colors used in inkjet printers, and found distinctive spectral features depending on the supplier of the ink. We analysed discontinued bank notes, and identified discrepancies in the SWIR response of allegedly genuine notes of different ages. This may either reveal information on the history of the note as a legal tender, or reveal the fake nature of a note sold as genuine. These observations may be useful in the identification of high-fidelity counterfeit documents, or bank notes.