Digital Watermarking for Image Authenticity Verification
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Solution Overview
Problem
Digital video surveillance systems face challenges in detecting and localizing spatial and temporal manipulations of images, with existing solutions lacking reliability and adaptability to specific system constraints, particularly in transcoding between JPEG and MPEG standards and computational limitations of devices.
Innovation Solution
A method for inserting and extracting digital watermarks that uses a secret key to select image blocks and coefficients, mapping values onto variable-sized vectors, and quantizing them to minimize distortion, allowing for robustness and imperceptibility, while ensuring authenticity and integrity verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital watermarking is used to detect image manipulations, then image authenticity and manipulation detection capability are improved, but computational complexity and processing time increase
Solution Approach 1:
The image is divided into multiple non-overlapping blocks, and watermarking is applied independently to each block. This segmentation reduces the computational complexity per block while maintaining overall reliability through distributed verification across all blocks.
Solution Approach 2:
Different watermarking strategies are applied to different image blocks based on local characteristics. Some blocks use more robust watermarking for critical regions, while others use lighter watermarking, optimizing the balance between reliability and computational load for each local region.
2Reliability
If robust watermarking techniques are applied to withstand image modifications, then watermark reliability is improved, but image quality and imperceptibility deteriorate
Solution Approach 1:
The watermarking strength and parameters are dynamically adjusted based on the local image characteristics and the desired level of robustness. This allows the system to optimize the balance between watermark reliability and image quality for each specific region and application scenario.
Solution Approach 2:
Watermarking parameters such as embedding strength, block size, and transformation domain are changed and optimized to achieve the desired robustness while minimizing impact on image quality. Different parameter sets are used for different application requirements.
3Ease of manufacture
If existing watermarking methods are used, then implementation is simpler, but adaptability to different video surveillance systems and standards deteriorates
Solution Approach 1:
The watermarking method is designed to be universally applicable to different video surveillance systems and image formats. It supports multiple transformation domains (spatial, DCT, wavelet) and can be integrated with various compression standards, making it adaptable to different system requirements while maintaining a unified implementation framework.
Data Source
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AI summary
The invention relates to a method for marking a digital document, especially a digital image, with a digital watermark for the purpose of manipulation recognition while inserting an integrity information and at least one multibit message. The method according to the invention comprises the following steps: converting the digital image to a converted digital image; dividing up the converted digital image into a plurality of blocks, every block having a plurality of coefficients; establishing a plurality of mapped message values for the at least one message, a plurality of first coefficients being mapped onto a vector that depends on a secret key; inserting every bit of every message into at least one of the mapped message values; establishing a plurality of mapped integrity values for the integrity information, a plurality of second coefficients being mapped onto a message-dependent vector, said message-dependent vector being derived from at least one of the messages and the secret key; inserting every piece of the integrity information into at least one of the mapped integrity values; updating every first coefficient that is used for establishing the mapped message values, using the inserted mapped message values, thereby achieving that the mapping of the updated first coefficients onto the secret key-dependent vector and the inserted mapped message values is identical; and updating every second coefficient that is used to calculate the mapped integrity values, using the inserted mapped integrity values, thereby achieving that the mapping of the updated second integrity coefficients onto the message-dependant vector and the inserted mapped integrity values is identical.