Image Processing Device Selecting Sparse Color Regions for Watermark Embedding
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Solution Overview
Problem
Detecting watermarks embedded in images can be challenging, especially in regions with gradual color changes, as the pixel value changes may not be distinguishable from adjacent pixels, making it difficult to identify the watermark.
Innovation Solution
An image processing device and method that acquire image data, generate histograms for each region, select regions with sparse color distributions, and embed watermarks in these regions, ensuring easier detection by altering pixel values in each color channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a watermark is embedded in a region with color gradation, then the watermark can be embedded in the image, but the pixel value changes become indistinguishable from adjacent pixels, making watermark detection difficult
Solution Approach 1:
The patent applies local quality by selecting specific regions with uniform color characteristics for watermark embedding. Instead of embedding watermarks uniformly across the entire image, the system analyzes color histograms to identify regions where color values are consistent and uniform, then embeds watermarks only in those suitable regions. This ensures that watermark-induced pixel changes remain distinguishable from natural image variations.
Solution Approach 2:
The patent utilizes parameter changes by analyzing color histogram parameters to identify suitable embedding regions. The system calculates color histograms for different image regions and selects regions based on specific parameter characteristics (uniformity, sparsity). By changing the selection criterion from arbitrary or uniform sampling to histogram-based parameter analysis, the system ensures watermarks are placed in regions where detection is most reliable.
2Loss of information
If pixel values are changed to embed a watermark, then the watermark information is stored in the image, but the changes may blend with natural pixel variations in gradation regions, reducing detection accuracy
Solution Approach 1:
The patent applies local quality by selecting specific regions with uniform color characteristics for watermark embedding. Instead of embedding watermarks uniformly across the entire image, the system analyzes color histograms to identify regions where color values are consistent and uniform, then embeds watermarks only in those suitable regions. This ensures that watermark-induced pixel changes remain distinguishable from natural image variations.
Solution Approach 2:
The patent applies preliminary action by performing color histogram analysis and region selection before watermark embedding. The system pre-identifies suitable embedding regions by calculating color histograms and evaluating region uniformity, then stores this region information for use during watermark embedding and subsequent detection. This preliminary region characterization ensures that when watermarks are embedded, the detection process can reliably identify the same regions and distinguish watermark-induced changes.
Data Source
AI summary
Certainty of detecting a watermark embedded in a color image is increased. Image data acquisition means of an image processing device acquires image data. Histogram generation means generates, based on pixel values of an image indicated by the image data acquired by the image data acquisition means, a histogram for each region in the image. Region selection means selects tom the image a region having a sparse color distribution in the histogram generated by the histogram generation means. Image processing means embeds a watermark in the region selected by the region selection means.