Template-Based Watermarking for DIBR 3D Image Copyright Protection
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Solution Overview
Problem
Current watermarking techniques for depth-image-based rendering (DIBR) are inadequate in protecting the copyright of DIBR 3D images, as they struggle with non-linear geometric distortions and are not robust against various attacks such as noise, cropping, and depth map preprocessing.
Innovation Solution
A template-based watermarking method that inserts and extracts watermarks using an improved angle quantization index modulation (IAQIM) scheme, dividing the image into specific blocks and transforming them into frequency domains to ensure robustness against DIBR transformations, while synchronizing geometric properties to maintain watermark integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a 2D watermark of the related art is used for DIBR images, then the watermarking process is simple, but the watermark detection becomes difficult due to non-linear geometric distortion
Solution Approach 1:
The image is divided into multiple blocks, and watermarks are embedded independently in each block. This segmentation approach allows the watermark to be distributed across the image in a way that maintains detectability despite DIBR-induced geometric distortions, as each block's watermark can be detected independently
Solution Approach 2:
The patent embeds watermarks in the frequency domain rather than the spatial domain, and uses multiple dimensions (horizontal and vertical frequencies) to embed watermark information. This dimensional transformation makes the watermark more robust against geometric distortions caused by DIBR
2Difficulty of detecting and measuring
If a watermark is inserted by predicting pixel movement using depth image, then watermark detection is easy after DIBR, but the watermark is weak when depth factor value is changed
Solution Approach 1:
The patent embeds watermarks in the frequency domain before any DIBR processing occurs. By performing the watermark embedding in advance in a transformed domain, the watermark becomes inherently more robust to subsequent geometric transformations and parameter changes, eliminating the need for depth-based prediction
Solution Approach 2:
The patent changes the domain parameter from spatial to frequency domain for watermark embedding. This parameter change makes the watermark representation more stable under DIBR transformations and depth factor adjustments, as frequency domain representations are less sensitive to geometric distortions
3Reliability
If quantization scheme is applied to DT-CWT domain for watermark insertion, then the technique is robust against DIBR and JPEG compression, but the number of inserted bits is limited
Solution Approach 1:
The patent divides the image into multiple blocks and embeds watermarks in each block independently. This segmentation enables parallel embedding of multiple watermark bits across different blocks, significantly increasing the total number of insertable bits while maintaining robustness through the distributed nature of the embedding
Solution Approach 2:
The patent embeds watermarks in multiple frequency sub-bands of the DT-CWT decomposition, not just in the coarsest band. This partial extension to finer frequency bands increases the capacity for watermark insertion while maintaining robustness, as the watermark energy is distributed across multiple frequency components
Data Source
AI summary
Provided are a template-based watermarking method for a DIBR 3D image and an apparatus thereof. The method includes: determining a template watermark inserting area and a message watermark inserting area in spatial domain of an image; transforming the determined template watermark inserting area into a frequency domain to insert at least one preset template watermark and transforming the determined message watermark inserting area into a frequency domain to insert a preset message watermark; and transforming the template watermark inserting area, into which the template watermark is inserted, into a spatial domain and transforming the message watermark inserting area, into which the message watermark is inserted, into a spatial domain.