Tint Block Image Generation Using Local Screen Ruling Adjustments
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing tint block technologies face challenges in maintaining high concealment capability for the latent image in the original and high identification capability for the latent image in copies, due to issues such as high density enhanced areas and low density enhanced areas at the boundary between the latent image and background portions, and differences in the appearance of camouflage patterns between the latent image and background portions.
Innovation Solution
A tint block image generation method that uses area modulation screens with different screen rulings for the latent and background portions, where the latent image portion is processed with a low screen ruling and the background portion with a higher screen ruling, and the halftone dots are generated at the center of gravity position, ensuring that the camouflage pattern's grayscale values are corrected based on the input grayscale values of both portions to maintain uniformity and concealment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If area modulation screens with different screen rulings are used for latent and background portions, then the concealment capability in the original is improved, but high density enhanced areas and low density enhanced areas are generated at the boundary
Solution Approach 1:
The patent applies different screen rulings locally to different portions of the tint block image. The latent image portion uses a first screen ruling while the background portion uses a second screen ruling. This local differentiation allows the latent image to maintain concealment capability while the background provides sufficient detail, resolving the contradiction between concealment and boundary uniformity.
Solution Approach 2:
The patent changes the screen ruling parameter between different portions of the image. By adjusting the screen ruling from the first value (for latent image) to the second value (for background), the system optimizes both concealment capability and boundary density uniformity, preventing the generation of high or low density enhanced areas at boundaries.
2Stability of the object's composition
If camouflage pattern grayscale values are corrected based on input grayscale values, then the appearance uniformity between latent and background portions is improved, but the processing complexity increases
Solution Approach 1:
The patent uses feedback by correcting the camouflage pattern grayscale values based on the input grayscale values of the latent and background portions. This feedback mechanism ensures that the camouflage pattern maintains consistent appearance across different portions of the image, achieving uniformity while managing processing complexity through systematic correction.
3Object-affected harmful factors
If dispersed dots are used in the background portion, then the dots cannot be easily read when copying, but the identification capability of the latent image in copies is reduced
Solution Approach 1:
The patent applies different dot arrangements locally: clustered dots in the latent image portion and dispersed dots in the background portion. This local differentiation ensures that the latent image remains identifiable in copies while the background provides copying difficulty, resolving the contradiction between these two requirements.
Data Source
AI summary
A image generation device generates, on a print medium, an image including a first image portion and a second image portion. The device has a first screen processing unit which generates image data by an area modulation screen having a first screen ruling, for pixels of the first image portion; and a second screen processing unit which generates image data by an area modulation screen or a density modulation screen having a second screen ruling which is higher than the first screen ruling for pixels of the second image portion. And the first screen processing unit generates a halftone dot at a center of gravity position of an image of the first image portion in a cell corresponding to a halftone dot formation area in the area modulation screen processing.