Hierarchical watermark detector

• US 20060062428A1
• Filed: 09/14/2005
• Published: 03/23/2006
• Est. Priority Date: 09/17/2004
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Alattar, Adnan M., Alattar, Osama M.
• Granted Patent: US 8,891,811 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06V 20/46 Extracting features or characteristics from the video content, e.g. video fingerprints, representative shots or key frames
• CPC Class Codes: H04N 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32267 combined with processing of the image
• 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

Abstract

The present invention relates generally to digital watermarking. In one implementation, we provide a hierarchical digital watermark detector method. The method includes: i) in a first layer of a hierarchical search, performing watermark detection on blocks of at least a portion of an incoming suspect signal; ii) identifying a first block in the portion that is likely to include a decodable digital watermark; and iii) in a second layer of the hierarchical search, performing additional watermark detection on overlapping blocks in a neighborhood around the first block. Another implementation provides a hierarchical watermark detector including a buffer and a detector. The buffer stores portions of an incoming signal. The detector evaluates watermark detection criteria for blocks stored in the buffer, and hierarchically zooms into a neighborhood of blocks around a block associated with watermark detection criteria that satisfies detection criteria.

Claims

1. A hierarchical digital watermark detector method comprising:

in a first layer of a hierarchical search, performing watermark detection on blocks of at least a portion of an incoming suspect signal;

identifying a first block in the portion that is likely to include a decodable digital watermark; and

in a second layer of the hierarchical search, performing additional watermark detection on overlapping blocks in a neighborhood around the first block.

2. The method of claim 1 including performing subsequent watermark detection operations on blocks in subsequent layers of the hierarchical search, where each subsequent layer is identified based on detection criteria evaluated from a previous layer.

3. The method of claim 1 including accumulating watermark decoding results from partial watermark decoding from blocks that do not provide a successful watermark decoding of a watermark message.

4. The detector of claim 1 wherein the incoming suspect signal represents at least one of image content and video content.

5. A hierarchical watermark detector comprising:

a buffer for storing portions of an incoming signal;

a detector for evaluating watermark detection criteria for blocks stored in the buffer, and for hierarchically zooming into a neighborhood of blocks around a block associated with watermark detection criteria that satisfies detection criteria.

6. The detector of claim 5 wherein the detector is replicated in parallel modules for operating on parts of the incoming signal in parallel.

7. The detector of claim 5 wherein part of the detector used to evaluate an initial layer in a hierarchical search is implemented in hardware logic, and part of the detector used to evaluate blocks in the neighborhood is implemented in instructions executing in a processor.

8. The detector of claim 5 wherein the incoming signal represents at least one of image content and video content.

9. A method comprising:

receiving a portion of a signal representing image or video content;

segmenting the portion into areas; and

for each area;

determining whether an area includes digital watermark characteristics,

determining which out of a plurality of areas includes preferred digital watermark characteristics;

and for an area including preferred digital watermark characteristics, expanding a search at or around the area to decode a digital watermark payload.

10. The method of claim 9 wherein the portion comprise a strip of image or video data.

11. The method of claim 9 wherein the preferred digital watermark characteristics comprise watermark orientation clues.

12. The method of claim 9 wherein the payload comprises a plural-bit payload.

13. The method of claim 12 wherein the payload includes or points to processing or handling instructions for the image or video content.

14. The method of claim 9 wherein the watermark characteristics comprise transform domain characteristics.

15. The method of claim 9 wherein the watermark characteristics are discovered through use of an image or video transformation.