Low-Frequency Digital Watermarking for Image Resilience
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Solution Overview
Problem
Existing digital watermarking techniques are ineffective in surviving image alterations such as cropping, compressing, and re-encoding, as they often rely on high-frequency components that are easily detectable and removable.
Innovation Solution
The implementation of low-frequency digital watermarks that are difficult to detect and remove, applied as subtle modifications to digital images or video frames, using patterns like sinusoidal waves or gradient bars that encode data in a way that is resilient to transcoding and compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high-frequency digital watermarks are used, then the watermark can be easily embedded in the image, but the watermark is easily detectable and removable through image alterations
Solution Approach 1:
The patent changes the frequency parameter of the watermark from high-frequency to low-frequency components. This parameter change makes the watermark less detectable and more resistant to removal through typical image processing operations like cropping, compressing, and re-encoding, while still allowing for effective embedding in the image data
2Difficulty of detecting and measuring
If low-frequency digital watermarks are used, then the watermark is difficult to detect and remove, but the watermark encoding requires more subtle modifications
Solution Approach 1:
The patent applies different watermarking strategies to different regions or frequency bands of the image. By targeting specific low-frequency components and applying subtle modifications only where necessary, the system achieves both low detectability and acceptable encoding precision without requiring excessive modification across the entire image
3Reliability
If the watermark is made resilient to transcoding and compression, then the watermark survives image alterations, but the watermark encoding becomes more complex
Solution Approach 1:
The patent divides the image into frequency domains (e.g., using transforms like DCT or wavelet transforms) and applies watermarking selectively to specific frequency bands. This segmentation allows the system to target low-frequency components that are more resilient to compression and transcoding, while keeping the encoding process manageable by working with divided frequency segments rather than the entire image at once
Data Source
AI summary
Techniques and mechanisms described herein facilitate the watermarking of images. According to various embodiments, a watermark image to apply to a digital image is identified. The digital image may include a plurality of image pixel data values. Each of the image pixel data values may designate a color of a corresponding pixel in the digital image. The watermark image may include a plurality of watermark pixel data values. Each of the watermark pixel data values may designate a color change to a corresponding pixel. The watermark image may be of relatively low frequency and may exhibit relatively gradual transitions and relatively constant color tone. The watermark image may be superimposed on at least a portion of the digital image to create a watermarked digital image.