Color-Difference Modulation for Invisible Digital Watermark Embedding
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Solution Overview
Problem
Existing image processing technologies face challenges in embedding sub-information in main image information without degrading image quality and ensuring the sub-information remains invisible, particularly in thermal transfer recording systems, where gradation performance and security are compromised.
Innovation Solution
An image processing apparatus and method that employs color-difference correction and modulation processes, along with synthesis and superposition techniques, to embed sub-information in a way that maintains image quality and security by using multiple color-difference amount correction and modulation sections, a synthesis processing section, and a superposition processing section to create synthesized image information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sub-information is embedded in main image information using electronic watermark technique, then security against forgery and falsification is improved, but image quality may be degraded and the embedded sub-information may become detectable
Solution Approach 1:
The patent applies local quality by performing color-difference correction and modulation in specific color difference components (Cb and Cr) where human visual sensitivity is lower. The sub-information is embedded selectively in regions and color channels that minimize visual impact while maintaining security functionality.
Solution Approach 2:
The patent utilizes color changes by embedding sub-information through modulation of color difference components (Cb and Cr) rather than luminance. This approach exploits the fact that human eyes are less sensitive to color variations than brightness variations, allowing secure embedding while preserving perceived image quality.
2Reliability
If sub-information is embedded in main image information, then security information is added, but the embedded sub-information may be destroyed or altered during thermal transfer recording
Solution Approach 1:
The patent applies preliminary action by performing robust color-difference correction and modulation processing before the thermal transfer recording step. The sub-information is embedded in a manner that anticipates potential degradation during recording, using correction amounts that compensate for expected thermal transfer effects.
Solution Approach 2:
The patent implements beforehand cushioning by incorporating error compensation mechanisms in the color-difference modulation process. The system prepares for potential information loss during thermal transfer by embedding redundant information and using correction amounts that cushion against anticipated degradation.
3Manufacturing precision
If color-difference correction and modulation processes are applied to embed sub-information, then image quality is maintained, but the processing complexity increases
Solution Approach 1:
The patent applies taking out by extracting the sub-information embedding process into separate color-difference correction and modulation modules. This modular approach isolates the complex processing from the main image processing pipeline, making the system more manageable despite the increased complexity.
Solution Approach 2:
The patent uses color difference components (Cb and Cr) as intermediaries between the main image information and the embedded sub-information. These intermediary color channels serve as a buffer that protects the luminance information while carrying the hidden data, reducing the direct impact of complex processing on perceived image quality.
4Adaptability or versatility
If thermal transfer recording is used to record synthesized image information, then recording versatility is improved, but gradation performance and image durability are degraded
Solution Approach 1:
The patent applies parameter changes by transforming the sub-information embedding from the luminance domain to the color-difference domain. This parameter transformation allows the use of thermal transfer recording with its coarser gradation, as the embedded information resides in color channels where thermal transfer's limitations have less impact on both image quality and data integrity.
Data Source
AI summary
An image processing apparatus corrects color-difference amounts of main image information by a plurality of color-difference amount correction processes and performs a plurality of color-difference modulation processes based on the processing results of the plurality of color-difference amount correction processes and a plurality of key information items. Further, it subjects the processing results of the plurality of color-difference modulation processes to the selecting/synthesizing process based on sub-information and superposing the processing result of the selecting/synthesizing process on the main image information to form synthesized image information having sub-information embedded in an invisible state in the main image information.