Motion Picture Watermarking via Temporal Dynamics
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Solution Overview
Problem
Watermarking motion pictures is challenging due to the need for different watermarks in each image to avoid visual perceptibility and withstand various image processing operations, which increases computational complexity and storage requirements, while maintaining data quality and robustness.
Innovation Solution
Embedding unique, temporally uncorrelated watermark images in motion pictures by using a permutation and mix operator with structured watermarks and keys, allowing for real-time embedding and detection, even in the presence of attacks, by modifying frequency domain coefficients and using a watermark sequence to manage the embedding and detection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same watermark is used in each image of a motion picture, then the watermarking process is computationally simple and storage requirements are low, but the watermark becomes visually perceptible during playback
Solution Approach 1:
The patent applies dynamics by making the watermark temporal - it evolves over time across frames rather than being static. The watermark signal varies from frame to frame, creating a temporal pattern that is imperceptible in individual frames but detectable when aggregated across multiple frames. This temporal dynamics resolves the contradiction by making the watermark invisible in static views while maintaining its presence through temporal correlation.
Solution Approach 2:
The patent employs periodic action through the temporal repetition and correlation of watermark signals across frames. The watermark follows a predetermined temporal pattern that repeats or correlates across frames, allowing detection through aggregation. This periodic temporal structure enables the watermark to be imperceptible in individual frames while being detectable when viewed across the temporal sequence, resolving the visual perceptibility issue.
2Object-generated harmful factors
If different watermarks are embedded in each image to avoid visual perceptibility, then the watermark robustness and imperceptibility are improved, but computational complexity and storage requirements increase
Solution Approach 1:
The patent applies universality by using a single predetermined temporal waveform that serves multiple functions across all frames. Rather than generating unique watermarks for each frame, the same temporal signal is applied across the sequence, providing both imperceptibility and robustness simultaneously. This universal temporal pattern resolves the contradiction by achieving protection goals without the computational burden of frame-specific watermark generation.
Solution Approach 2:
The patent uses parameter changes by modulating the watermark signal's temporal characteristics rather than its spatial content. The watermark maintains a consistent structural pattern but varies in its temporal application across frames. This parameter-based approach (changing temporal parameters rather than spatial content) achieves imperceptibility and robustness while keeping the watermarking process computationally efficient.
3Reliability
If watermarks are made robust to withstand image processing operations, then the watermark detection reliability is improved, but the embedded information may become visually perceptible
Solution Approach 1:
The patent resolves this contradiction by moving the watermark from the spatial dimension to the temporal dimension. Instead of embedding visible spatial patterns that could be enhanced by processing operations, the watermark exists as a temporal signal across frames. Image processing operations typically affect spatial content, leaving temporal correlations intact, thus maintaining robustness without increasing visual perceptibility.
Solution Approach 2:
The patent uses temporal correlation as an intermediary mechanism between the watermark signal and detection. Rather than relying on spatial features that may be enhanced by processing, the watermark's robustness comes from its temporal correlation pattern. This temporal intermediary allows the watermark to withstand spatial processing operations while remaining imperceptible, as the correlation is established across time rather than space.
Data Source
AI summary
The problem of watermarking a sequence of images from a motion picture can be divided into two parts. The first part is embedding watermarks in the sequence of images. The second part is detecting embedded watermarks in a target sequence of images where the target sequence may have resulted from one or more attacks on an original sequence of images in which the watermarks were embedded. Motion pictures are watermarked by embedding information in different ways in different images. In general, the information to be embedded is used to define a plurality of watermark images. Each watermark image is an apparent pattern of noise in both signal and frequency domains, and is different from the other watermark images. Preferably, each watermark image is temporally uncorrelated with the other watermark images. Each watermark image is used to modify a corresponding image from the motion picture. To detect the presence of the information in a target sequence of images from a motion picture, the target images are processed to determine an alignment with a watermark sequence. When an alignment with the watermark sequence is determined, a sliding window detector is applied to detect the watermark and read the information embedded by the watermark. By embedding the same information in different ways in different images, and then detecting this information by combining data from the different images, the sensitivity of the detector is increased.