Covert Image Edge Emphasis for Identification Card Printing
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Solution Overview
Problem
Current methods struggle to print high-quality, identification-quality images using covert materials like UV, IR, and thermachromic inks, as these images often suffer from a 'washed-out' effect, making it difficult to rely on them for authentication due to blurred details.
Innovation Solution
Enhancing digital images before printing by increasing contrast, detecting and emphasizing edges, and dithering to improve the visibility and crispness of covert images, which can be printed using UV, IR, or thermachromic inks, and embedding steganographic codes for additional security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If covert materials like UV, IR, and thermachromic inks are used for printing identification images, then security and authenticity verification is improved, but image quality deteriorates due to washed-out effect and blurred details
Solution Approach 1:
The patent applies preliminary image processing actions (contrast enhancement, edge detection, edge emphasis, and dithering) to the digital image before printing with covert materials. This preprocessing compensates for the inherent washed-out effect of UV, IR, and thermachromic inks, ensuring that the final printed image maintains identification-quality sharpness and detail while retaining authentication reliability
Solution Approach 2:
The patent applies different processing techniques to different regions of the image based on local requirements. Edge detection and emphasis are applied specifically to boundaries and critical features, while dithering is applied to grayscale areas, ensuring that each region of the covert image receives optimized treatment to maintain overall image quality despite the limitations of covert printing materials
2Adaptability or versatility
If covert images are printed with UV, IR, or thermachromic inks, then security features are enhanced, but image visibility and crispness deteriorate due to the washed-out effect
Solution Approach 1:
The patent modifies key parameters of the digital image (contrast, edge detection thresholds, emphasis strength, and dithering patterns) to optimize the final printed output. By adjusting these parameters before printing, the system compensates for the reduced visibility inherent in covert materials, ensuring that the printed images maintain sufficient crispness and detail for identification purposes while preserving the security benefits of using UV, IR, or thermachromic inks
Data Source
AI summary
The invention relates to identification documents, and in particular to pre-printing processing covert images, such as UV or IR images, provided on such identification documents. In one implementation, the invention includes a method of processing a digital image that is to be printed on a surface of an identification document as a fluorescing-capable image to improve the quality of the image. Edges or boundaries are detected within the image, the detected edges or boundaries forming an intermediate image. The edges or boundaries within the image are emphasized, and the emphasized image is used for printing the covert image. In some implementations of the invention, a digital watermark is embedded in the covert image.