Parallel processing of digital watermarking operations

• US 20020120849A1
• Filed: 11/02/2001
• Published: 08/29/2002
• Est. Priority Date: 02/14/2000
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M., Rhoads, Geoffrey B., Rodriguez, Tony F., McKinley, Tyler J., Hein, William C. III
• Granted Patent: US 8,355,525 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: G06F 16/48 Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
• CPC Class Codes: G06F 16/78 Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
• CPC Class Codes: G06Q 40/04 Trading; Exchange, e.g. stocks, commodities, derivatives or currency exchange
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 2201/0064 for copy protection or copy management, e.g. CGMS, copy only once, one-time copy
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32288 Multiple embedding, e.g. cocktail embedding, or redundant embedding, e.g. repeating the additional information at a plurality of locations in the image
• CPC Class Codes: H04N 1/32352 Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3284 for error correction

Abstract

The disclosure describes a method of segmenting a media signal for parallel watermarking operations. The method 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. The disclosure also describes a system for distributed watermark embedding operations including a watermark signal generator, a perceptual analyzer and a watermark applicator. These components are implemented as modules that can operate independently in a distributed processing environment. To further enhance parallelism, the system segments a host media signal into segments for parallel processing on these modules. As such, 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.

Claims

1. 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.

2. The method of claim 1 including:

analyzing a media signal to prioritize segments of the media signal for digital watermark operations on the segments.

3. The method of claim 2 wherein the media signal segments are prioritized for digital watermark embedding operations.

4. The method of claim 3 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.

5. The method of claim 2 wherein the media signal segments are segmented and prioritized by color.

6. The method of claim 2 wherein the media signal segments are prioritized for watermark embedding based on analysis of the media signal that indicates the printing distortion expected for the segments.

7. The method of claim 2 wherein the media signal segments are prioritized for watermark embedding based on likelihood of watermark survival through rendering, compression or transmission distortion.

8. The method of claim 7 wherein the watermark embedding is limited to a predetermined resource constraint limiting amount of watermark embedding before transmission, rendering or broadcast of the watermarked media signal generated by the watermark embedding.

9. The method of claim 1 wherein the media signal is segmented spatially into contiguous blocks for parallel watermark operations.

10. The method of claim 1 wherein the media signal is segmented into plural different resolution signal segments, and parallel watermark operations are performed on the plural different segments.

11. The method of claim 1 wherein the media signal is segmented based on processing bandwidth available for the watermark operations.

12. The method of claim 1 wherein the media signal is segmented and prioritized for watermark operations based on a mask used to control the watermark operations.

13. The method of claim 12 wherein the media signal comprises an image and the segments are prioritized for watermark embedding or decoding based on a color component mask.

14. The method of claim 1 wherein the media signal is segmented into blocks based on a memory parameter of processing hardware.

15. The method of claim 14 wherein the memory parameter comprises a unit of memory used to swap data into system memory in a virtual memory system.

16. The method of claim 14 wherein the memory parameter comprises a memory alignment boundary.

17. The method of claim 1 wherein the media signal is segmented and prioritized based on bit plane to reduce the number of bit planes of the media signal subjected to watermarking operations.

18. The method of claim 1 wherein the media signal is segmented and prioritized for parallel watermark decoding operations based on probability of watermark detection.

19. The method of claim 1 wherein the parallel processors comprise threads of execution on one or more hardware processing units.

20. The method of claim 1 wherein the watermark operations are performed by two or more watermark operation modules, and the watermark operation modules operate in parallel.

21. The method of claim 20 wherein the watermark operation modules comprise a watermark generator, a perceptual analyzer and a watermark applicator.

22. A computer readable medium on which is stored instructions for performing the method of claim 1.

24. The embedder of claim 23 wherein the distributed processors comprises independent threads of execution.

25. The embedder of claim 23 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 re-used by the watermark applicator to apply different watermarks from the watermark signal generator to the copies.

26. The embedder of claim 23 including a media signal segmentation processor for sub-dividing a media signal into segments for parallel processing in the embedder.

27. The embedder of claim 26 wherein the embedder includes plural perceptual analyzers, which operate in parallel on segments of the media signal.

28. The embedder of claim 26 wherein the embedder includes plural watermark signal applicators, which operate in parallel on segments of the media signal.

30. The system of claim 29 wherein the segments are prioritized for embedding operations.

31. The system of claim 30 wherein the segments are prioritized for embedding operations based on readability of a watermark.

32. The system of claim 30 wherein the segments are prioritized for embedding operations based on hardware resource constraints.

33. The system of claim 32 including a load balancer for distributing segments to the parallel processors based on priority.

23. 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.

29. A system for parallel watermark embedding comprising:

a media signal pre-processor operable to receive a media signal and divide the media signal into segments for parallel watermark embedding operations; and

a server for distributing the segments to parallel processors for parallel watermark embedding operations.

34. A batch digital watermark registration and embedding system comprising:

a network interface for receiving ID registration requests, the requests including a list of media signal files and information to be linked with the media signal files via data embedded in the media signal files;

a batch registration loader for creating records in a registration database corresponding to identifiers for each of the media signal files;

a batch registration extractor for reading the registration database and creating an embedder control file, including identifiers, a corresponding list of media signal files, and embedding instructions for controlling embedding of the identifiers in the media signal files; and

a parallel digital watermark embedder for segmenting media signal files into segments and for distributing the segments to parallel processors for performing parallel digital watermark embedding operations on the segments to hide the identifiers in the media signal files.