Adaptive Pixel Watermarking for Recaptured Video
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Solution Overview
Problem
Existing electronic watermark technologies for recaptured images often degrade image quality and are prone to visual disturbances, making them ineffective for maintaining copyright protection without compromising the quality of the target image.
Innovation Solution
An electronic watermark embedding method that divides images into regions, extracts adaptive pixels, and varies pixel values in a way that minimizes visual disturbance, ensuring the watermark is resistant to recapturing while maintaining image quality, combined with a detection method that uses Gap and correlation detection to accurately identify embedded bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brightness variations with respect to time direction are provided as electronic watermark to moving image, then copyright protection is enabled for recaptured images, but light or dark portions appear during playback depending on the target moving image
Solution Approach 1:
The patent applies local quality by selecting specific pixels (adaptive pixels) within each block for watermark embedding based on their individual characteristics. Pixels are classified into bright, dark, and intermediate categories, and watermark embedding is performed differently for each category to minimize visual disturbance while maintaining detection reliability.
Solution Approach 2:
The patent embeds watermark information in both spatial and temporal dimensions. By varying pixel values across frames and using correlation detection between adjacent frames, the system achieves robust copyright protection while controlling visual artifacts through multi-dimensional embedding.
2Quantity of substance
If each frame image is spatially divided into plurality of regions and brightness modulation is performed on each region, then amount of electronic watermark embedding is increased, but boundary lines between divided regions appear during playback
Solution Approach 1:
The patent divides the image into blocks and further into regions, but applies different embedding strategies to different pixel types within each region. Bright pixels use one embedding pattern, dark pixels use another, and intermediate pixels use a third, which prevents uniform boundary artifacts while maintaining high embedding capacity.
Solution Approach 2:
The patent changes the embedding parameters (variation amount, embedding pattern) based on pixel brightness characteristics and region location. By adaptively adjusting these parameters, the system increases watermark capacity while minimizing visible boundary effects through parameter optimization.
3Measurement precision
If brightness modulation is performed on divided regions to embed electronic watermark, then watermark detection capability is improved, but image quality degrades depending on the target moving image
Solution Approach 1:
The patent performs watermark embedding with different characteristics for bright, dark, and intermediate pixels. This local differentiation allows the system to maintain image quality by avoiding excessive modulation in regions where it would be most visible, while still achieving high detection precision through the cumulative effect across all pixel types.
Solution Approach 2:
The patent applies watermark embedding selectively to specific pixels based on their characteristics rather than uniformly to all pixels. This partial action approach concentrates embedding effort on pixels where it provides maximum detection benefit with minimum visual impact, optimizing the balance between detection precision and image quality.
Data Source
AI summary
An electronic image into which an electronic watermark is to be embedded is divided into a plurality of image regions spatially, and pixels each having a property of being difficult to visually recognize a variation in a pixel value are extracted as adaptive pixels from each of the plurality of image regions. A variation between the pixel values of the adaptive pixels in one of the plurality of image regions and those of the adaptive pixels in an adjacent one of the plurality of image regions is produced, and the pixel values of the adaptive pixels of the plurality of image regions are varied in a time direction according to the value of an embedded bit set of the electronic watermark. An electronic-watermark-embedded image is then generated by making the variation in the pixel values of the adaptive pixels vary step by step at a boundary between the two of the plurality of image regions and/or in the time direction so that the variation makes a slow transition.