Empress Catherine II Saint Petersburg Mining University, Saint Petersburg, Russia:

A. P. Petkova, Professor at the Department of Materials Science and Technology of Art Products, Doctor of Technical Sciences, e-mail: Petkova_AP@pers.spmi.ru
O. Yu. Ganzulenko, Associate Professor at the Department of Materials Science and Technology of Art Products, Candidate of Technical Sciences, e-mail: Ganzulenko_OYu@pers.spmi.ru

The authors of this paper developed an original method to create colour matrix codes aimed at counterfeit protection of items, preventing unauthorized use of information, verifying the authenticity of items, ensuring their clear identification, increasing the ID capacity (text, graphical, audio and video information and other digital data) approximately by 5 times and creating a machine-readable template image of such ID. The proposed colour code helps transform the known black-and-white nanobarcode into a multi-dimensional colour code applied to a two-dimensional matrix or increase the nanobarcode capacity by several times. Multi-dimensional colour matrix codes enable to increase the amount of data contained in the colour code due to the use of a graphical two-dimensional matrix to which all layers of binary-coded data are applied. It is possible to create digital codes and apply codes to metal surface by printing or laser marking. Definition of reference colour cells ensures that the code will be read and decoded even if the technical characteristics of printers and scanners differ. The obtained colour palettes and databases of laser marking regimes applicable to titanium, copper and aluminium alloys ensure reproducibility of the main colours for all the mentioned materials. Through the use of four or eight colours in the colour matrix code instead of merely black and white in the two-dimensional one, the code capacity can be increased to two or three bits of information depending on the number of colour layers. By making use of four or eight stable colours, including the background colour, one can create two- and three-layer colour matrix codes on the surface of each of the above listed materials.
Candidate of Technical Sciences E. V. Larionova took an active part in the work, who formulated the principles of creating a 3-dimensional color nanobarkode.

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