International research data shows that due to the counterfeiting of products in 2017, global producer losses reached 1.2 trillion dollars and up to 1.82 trillion in 2020. This forecast covers the full range of products from pharmaceuticals to watches and consumer products. Currently, available security (anticounterfeiting) technologies have limited efficiency or are extremely sophisticated and expensive. Therefore, we propose a novel approach helping the manufacturers and users to protect themselves against counterfeit goods on the market by employing hyperspectral imaging technology based on a smartphone and multicolour (5-10 colours) flash. Dedicated software (application) synchronizes the operation of the camera and flash and shoot the same image under different lighting conditions. Superposition of narrow spectra illumination and camera sensor response functions results in an increased spectral resolution of the resulting image stack. Furthermore, as it is intended to include UV and IR illumination, this will extend the effective wavelength range and include fluorescence -up and -down conversion spectra of dedicated security ink and/or conventional polygraphy. Such a technique would be incomparably simpler and cheaper than analytical laboratory equipment and would allow the authentication to be brought closer to the end-user.
For the experimental trials, a smartphone Samsung Galaxy Note 10 Lite, capable to take photos in RAW format (.DNG), was used. Image J Fiji software was used to perform spectral image analysis, calibration and initial analysis. Sample colour prints printed by different commercial printers were analysed by recording diffuse reflectance. Sample reflectance spectra are presented in Fig. 1., and one can see that the different printers, performing “the same" colour result in different reflectance spectra which is almost indistinguishable by the naked eye but can be detected by hyperspectral imaging device.
We conclude that almost any consumer-grade camera can be transformed into the hyperspectral imaging device by adding smart multicolour flash. Such a system could have a vast applicability and anticounterfeiting is just one of the application areas.