Anti-counterfeit systems and methods
AssigneeNano and Advanced Materials Institute Limited
InventorsKa Wah HAU, Chi Ho KWOK, Lin CONG, Li FU
Life of this patent
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Abstract
An anti-counterfeit system including a dual-functional security ink composition exhibiting both near-infrared (NIR) absorption and visible coloration, characterized by a viscosity of 10-1,250 cP and a pH of 6-8, is provided. The system includes a security feature printing module for producing a machine-readable security feature detectable under visible light and NIR illumination at 700-1,000 nm. An image acquisition device, incorporating a portable NIR imaging camera or scanner and an optical camera, is used to capture corresponding NIR and optical images of the security feature. A computer system processes the captured NIR image through a multi-stage enhancement pipeline.
Claims20
An anti-counterfeit system, comprising:
- a dual-functional security ink composition exhibiting both near-infrared (NIR) absorption and visible coloration, having a viscosity of 10 to 1,250 cP and a pH between 6 and 8, comprising:
- a NIR absorbing compound in an amount ranging from 0.5% to 10% by weight (w/w);
- and
- one or more visible colorants in an amount ranging from 0.5% to 10% w/w;
- a security feature printing module configured to print a security feature using the dual-functional security ink composition, wherein the security feature is machine-readable under illumination with NIR light in the wavelength range of 700-1,000 nm;
- an image acquisition device comprising a portable NIR imaging camera or scanner configured to capture an NIR image of the security feature and an optical image camera configured to capture an optical image of the security feature;
- and
- a computer system configured to process the NIR image of the security feature through:
- applying a bilateral filtering to the NIR image to reduce noise while preserving edge features;
- performing a contrast-limited adaptive histogram equalization (CLAHE) on the filtered NIR image to enhance local contrast between inked regions and a background substrate;
- converting the contrast-enhanced image into a binary image using Otsu thresholding;
- performing image upscaling to improve resolution of the binary image;
- and
- generating an enhanced NIR image suitable.
A method of authenticating a security feature printed with a dual-functional ink composition, the method comprising:
- capturing a NIR image of the security feature using an NIR imaging device, the ink composition exhibiting NIR absorption in the wavelength range of 700-1,000 nm, wherein the security feature is in a visibly colored or a visibly colorless form;
- applying a bilateral filtering to the NIR image to reduce noise while preserving edge features;
- performing a CLAHE on the filtered image to enhance local contrast between inked regions and a background substrate;
- converting the contrast-enhanced image into a binary image using Otsu thresholding;
- performing image upscaling to improve resolution of the binary image;
- generating an enhanced NIR image;
- and
- comparing the enhanced NIR image with a stored reference image of the security feature to generate an authentication result;
- wherein the dual-functional ink composition exhibits both NIR absorption and visible coloration, having a viscosity of 10 to 1,250 cP and a pH between 6 and 8, comprising:
- a NIR absorbing compound in an amount ranging from 0.5% to 10% by weight (w/w), comprising one or more of:
- a nickel dithiolene derivative, having the formula:
- wherein R1 is a hydrogen atom, aryl, arylalkyl, substituted aromatic cycles containing halogen, halo alkyl, ester, imide, diimide, nitro, cyano, carbonyl, or sulfonyl group;
- a nickel phenylenediamine derivative, having the formula:
- wherein R2 is a hydrogen atom, aryl, arylalkyl, substituted aromatic cycles containing halogen, halo alkyl, ester, imide, diimide, nitro, cyano, carbonyl, or sulfonyl group;
- copper phosphate ester having the formula of CuPO3R3, wherein R3 is a hydrogen atom, alkyl or alkoxy group;
- and
- cesium tungsten oxide having the formula of:
- CsxWO3, wherein 0<x<1;
- and
- one or more visible colorants in an amount ranging from 0.5% to 10% w/w, comprising one or more of acid dyes, basic dyes, solvent dyes, direct dyes, disperse dyes, mordant dyes and reactive dyes.
Dependencies are inferred from the claim text.