Frequency-Modulated Chromatic Watermarking for Video Source Identification
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Solution Overview
Problem
Unauthorized copying and distribution of video content remain a significant issue despite legal restrictions, as it is difficult to trace the source of the initial unauthorized copy.
Innovation Solution
A method of encoding a unique identification code into video content using a periodic spatial pattern of chromatic variations with specific spatial frequencies, which can be detected through spectral analysis, allowing the source of the content to be identified and enabling appropriate action by the copyright owner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a watermark is embedded in video content to identify the source of unauthorized copies, then the ability to trace and identify the original distributor is improved, but the watermark may become perceptible to viewers, degrading the visual quality of the content
Solution Approach 1:
The watermark is embedded only in the chrominance components (color information) of the video signal, specifically in the I and Q channels, while leaving the luminance component (brightness information) unchanged. This local application of watermarking to specific color channels makes the watermark imperceptible to human viewers while maintaining source identification capability
Solution Approach 2:
The invention embeds the watermark by modulating the chromaticity coordinates (I and Q values) of the video signal. The watermark data is encoded as variations in color information rather than brightness, exploiting the fact that human vision is less sensitive to color variations than to luminance changes, thus making the watermark effectively invisible
2Object-affected harmful factors
If the watermark is made imperceptible by embedding it in chrominance components, then visual quality is maintained, but the detection and extraction of the watermark becomes more difficult
Solution Approach 1:
The system employs a dedicated watermark detection device that uses feedback mechanisms to analyze the chrominance components of received video signals. The detector compares the I and Q channel values against expected watermark patterns, using iterative analysis to extract the embedded identification code even from imperceptible variations
Solution Approach 2:
The invention replaces visual detection methods with electronic signal processing techniques. Instead of relying on human visual inspection, the system uses automated digital signal processing to analyze chrominance component variations, extract spatial frequency patterns, and decode the embedded watermark data through computational algorithms
3Object-affected harmful factors
If spatial frequency modulation is used to encode the data string, then the watermark can be embedded imperceptibly in chromatic variations, but the system complexity increases due to the need for spectral analysis
Solution Approach 1:
The watermark detection system performs preliminary separation of the chrominance components (I and Q channels) from the video signal before conducting spectral analysis. This pre-processing step organizes the data in a way that simplifies subsequent Fourier transform operations and makes the spatial frequency pattern extraction more efficient
Solution Approach 2:
The invention divides the watermark detection process into distinct segments: first separating chrominance components, then performing spatial Fourier transforms on each component independently, and finally combining the results to extract the embedded data string. This segmentation of the analysis process reduces overall system complexity by breaking down a complex task into manageable stages
Data Source
AI summary
A method for image processing includes storing a data string and applying a background modulation to an image. The modulation includes a periodic spatial pattern of chromatic variations over an area of the image with a constant luminance over the area and with a spatial frequency of the chromatic variations that encodes the data string. Related apparatus and methods are included.