Application of a Fourier-transform infrared imaging system to deciphering obliterated writings for forensic purposes
Shigeru Sugawara · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2014
A new method of deciphering obliterated writing is proposed in this paper. Inks with a peak at 1620 cm-1 were used for writing characters on paper, and information protection stamps were then used to obliterate them. Conventional detection methods consisting of visible and near-infrared spectroscopic photography and fluorescent photography of wavelength between 0.4–1.0 μm were compared with a novel method using infrared spectroscopic imaging with a 16-element mercury cadmium telluride array detector. The samples of obliterated writing could not be detected by the conventional methods, but could by the new method. Therefore, this new method is very useful for deciphering obliterated writing.