Dot Pattern Encoding Using Source Pixel Color Adaptation
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Solution Overview
Problem
Existing dot pattern encoding methods struggle to maintain visibility and detectability across various backgrounds, particularly when yellow dots are printed on colored backgrounds, leading to substantial portions of encoded information being undetectable.
Innovation Solution
The proposed techniques encode dot patterns based on source pixel color, using a method that modifies dot colors based on the original color of the source page pixels, allowing for flexible dot and background color combinations, and employing single channel detectability with minimal visual impact by using existing printing processes and inks, ensuring dot patterns can be recovered regardless of page content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If yellow dots are used to encode information on documents, then the dot pattern is substantially invisible to the human eye at normal reading distances, but the encoded information becomes undetectable when printed on colored backgrounds or with yellow content
Solution Approach 1:
The patent applies local quality by selecting different dot colors based on the specific background color at each location. Instead of using a uniform yellow dot color throughout the document, the system analyzes the background color of each pixel and assigns a dot color that provides both visual imperceptibility and detectability for that specific local region. This resolves the contradiction by making the dot pattern locally adapted to its background rather than globally uniform.
Solution Approach 2:
The patent changes the color parameter of the dots dynamically based on the background color. By adjusting the hue, saturation, and brightness parameters of the dot color to match the underlying background, the system maintains visual imperceptibility while ensuring detectability through color analysis. This parameter adaptation allows the same dot pattern to be invisible on diverse backgrounds without losing information detectability.
2Object-affected harmful factors
If dot patterns are made invisible by matching luminance with the background, then visual impact is minimized, but detection becomes unreliable on colored or yellow backgrounds
Solution Approach 1:
The system implements local quality by analyzing the background color characteristics at each pixel location and selecting dot colors that are locally optimized for both invisibility and detectability. Rather than applying a global luminance matching rule, the patent adapts the dot color properties to the specific local background, ensuring that detection remains accurate across varied colored backgrounds while maintaining minimal visual impact.
Solution Approach 2:
The patent employs color changes by dynamically adjusting the dot color to match the background color while maintaining a detectable color relationship. Instead of using fixed luminance matching, the system modifies the color parameters (hue, saturation, brightness) of the dots based on the underlying background color, enabling reliable color-based detection while preserving visual imperceptibility on colored and yellow backgrounds.
3Ease of manufacture
If a fixed dot color scheme is used for encoding, then the encoding process is simple and fast, but the dot pattern cannot be reliably detected on all background colors
Solution Approach 1:
The patent applies dynamics by making the dot color selection adaptive rather than static. The system dynamically determines the optimal dot color for each pixel based on the background color analysis, allowing the encoding process to adapt to diverse backgrounds. This dynamic approach maintains relatively simple encoding logic while significantly improving versatility across different document types and background colors.
Solution Approach 2:
The system changes the color parameters of the dots based on the background color to improve adaptability. By adjusting hue, saturation, and brightness parameters according to the underlying background, the patent achieves reliable detection across colored backgrounds while maintaining a systematic encoding approach. This parameter-based adaptation balances encoding simplicity with background versatility.
Data Source
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AI summary
In an example method, a set of source pixels corresponding to an image to be printed and a dot pattern of pixels including information to be encoded across the image are received. The dot pattern of pixels is mapped to a corresponding subset of the source pixels. A value of a clipping channel color in the subset of the source pixels is modified based on an original value of the clipping channel color for each pixel in the subset. The clipping channel color is used to detect the dot pattern of pixels. The image including the subset of pixels with modified clipping channel colors is printed.