Parallel processing of digital watermarking operations
A method of segmenting a media signal for parallel watermarking operations sub-divides the media signal into segments, distributes the segments to parallel processors, and performs parallel digital watermark operations on the segments in the parallel processors. These parallel processors may comprise separate threads of execution on a processing unit, or several execution threads distributed to several processing units. In one enhancement, the method prioritizes the segments for watermarking operations. This enables finite processing resources to be allocated to segments in order of their priority. Further, processing resources are devoted to segments where the digital watermark is more likely to be imperceptible and/or readable. A system for distributed watermark embedding operations includes a watermark signal generator, a perceptual analyzer and a watermark applicator. The system supports operation-level parallelism in the concurrent operation of watermark embedder modules, and data parallelism in the concurrent operation of these modules on segments of a media signal to be embedded with an imperceptible digital watermark.
1. A method of segmenting a media signal for parallel watermarking operations, the method comprising:
sub-dividing the media signal into segments based on analysis of the media signal to identify parts of media signal having signal characteristics that are more likely to carry a readable watermark signal;
analyzing the media signal to prioritize the segments of the media signal for digital watermark operations on the segments wherein the media signal segments are prioritized for digital watermark embedding operations and wherein the media signal segments are prioritized such that segments that are more likely to carry a readable watermark signal are given higher priority for the embedding operations;
distributing the prioritized segments to parallel processors; and
performing parallel digital watermark embedding operations on the prioritized segments in the parallel processors according to priority order of the prioritized segments.
2. A method of segmenting a media signal for parallel watermarking operations, the method comprising:
sub-dividing the media signal into segments;
distributing the segments to parallel processors; and
performing parallel digital watermark operations on the segments in the parallel processors wherein the media signal is segmented based on probability of watermark detection and prioritized for parallel watermark decoding operations based on probability of watermark detection.
3. The method of claim 2 wherein the parallel processors comprise threads of execution on one or more hardware processing units.
4. A distributed digital watermark embedder comprising:
a watermark signal generator for generating a watermark from a message;
a perceptual analyzer for perceptually analyzing a media signal and generating perceptual control parameters used to control application of the watermark to the media signal; and
a watermark applicator for receiving the media signal, the watermark and the perceptual control parameters, and for applying the watermark to the media signal according to the perceptual control parameters; wherein the watermark signal generator, the perceptual analyzer and the watermark applicator operate on distributed processors; wherein variable watermarks are embedded in copies of a media signal by executing the perceptual analyzer on the media signal once to generate a perceptual mask that is dependent on and automatically computed from the content of the media signal and is re-used by the watermark applicator to apply different watermarks from the watermark signal generator to the copies, the perceptual mask specifying areas of the media signal and is used to control embedding of the watermark in the areas.
5. The embedder of claim 4 wherein the distributed processors comprises independent threads of execution.
6. The embedder of claim 4 including a media signal segmentation processor for sub-dividing a media signal into segments for parallel processing in the embedder.
7. The embedder of claim 6 wherein the embedder includes plural perceptual analyzers, which operate in parallel on segments of the media signal.
8. The embedder of claim 6 wherein the embedder includes plural watermark signal applicators, which operate in parallel on segments of the media signal.