Detection from two chrominance directions

• US 9,582,844 B2
• Filed: 01/25/2016
• Issued: 02/28/2017
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M.
• Primary Examiner(s): GORADIA, SHEFALI DINESH
• Application Number:
  US15/005,865
• Publication Number:
  US 20160232639A1
• Time in Patent Office: 400 Days
• US Class Current: 1/1
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: H04B 1/3833 Hand-held transceivers
• CPC Class Codes: H04N 9/68 for controlling the amplitude of colour signals, e.g. automatic chroma control circuits H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86

Abstract

The present disclosure relates generally to signal processing, including processing digital watermarking. One claim recites a detector apparatus comprising: memory for storing data representing color image data comprising red color data and green color data, in which the red color data comprises digital watermarking including a first polarity and the green color data comprises the digital watermarking including a second polarity that is inversely related to the first polarity; means for selectively weighting the red color data and the green color data so that the digital watermarking is emphasized while image content is de-emphasized when weighted red color data and weighted green color data are combined; means for detecting the digital watermarking from combined, weighted red color data and weighted green color data; and more or more processors configured for outputting data corresponding to detected digital watermarking. Of course, different combinations and claims are provided too.

Claims

1. A detector apparatus comprising:

memory for storing data representing color image data comprising red color data and green color data, in which the red color data comprises digital watermarking including a first polarity and the green color data comprises the digital watermarking including a second polarity that is inversely related to the first polarity;

one or more processors programmed for;

selectively weighting the red color data and the green color data so that the digital watermarking is emphasized while image content is de-emphasized when weighted red color data and weighted green color data are combined;

detecting the digital watermarking from combined, weighted red color data and weighted green color data; and

outputting data corresponding to detected digital watermarking.

2. The detector apparatus of claim 1 in which combining the weighted red color data and the weighted green color data subtracts the weighted green color data from the weighted red color data.

3. The detector apparatus of claim 1 in which weighting aligns digital watermark detection along an a−

b direction, where a represents a first multi-color axis, and b represent a second multi-color axis.

4. A handheld device comprising the detector apparatus of claim 3.

5. A cell phone comprising the handheld device of claim 4.

6. The detector apparatus of claim 1 in which the weighted red color data and the weighted green color data are combined according to 0.35*red color data−

1.05*green color data.

7. The detector apparatus of claim 1 in which the image color data also comprises blue color data, and said selectively weighting the red color data and the green color data also selectively weights the blue color data so that the digital watermarking is emphasized while image content is de-emphasized when weighted red color data, weighted green color data and weighted blue color data are combined.

8. The detector apparatus of claim 7 in which the weighted red color data, the weighted green color data and the weighted blue color data are combined according to 0.35*red color data−

1.05*green color data+0.70*blue color data, plus a constant.

9. A detector apparatus comprising:

memory for storing data representing color image data comprising first color data and second color data, in which the first color data comprises digital watermarking including a first polarity and the second color data comprises the digital watermarking including a second polarity that is inversely related to the first polarity, and in which the first color data corresponds to a first multi-color axis, and the second color data corresponds to a second multi-color axis;

one or more processors programmed for;

combining the first color data and the second color data by subtracting the second color data from the first color data, the subtracting emphasizing the digital watermarking while de-emphasizing image content;

detecting the digital watermarking from the combined first color data and second color data; and

outputting data corresponding to detected digital watermarking.

10. A handheld device comprising the detector apparatus of claim 9.

11. A cell phone comprising the handheld device of claim 10.

12. The detector apparatus of claim 9 in which said combining aligns digital watermark detection along an a−

b color direction in an Lab color space.

13. A detector apparatus comprising:

memory for storing data representing color image data comprising red color data and green color data, in which the red color data comprises digital watermarking including a first polarity and the green color data comprises the digital watermarking including a second polarity that is inversely related to the first polarity;

means for selectively weighting the red color data and the green color data so that the digital watermarking is emphasized while image content is de-emphasized when weighted red color data and weighted green color data are combined;

means for detecting the digital watermarking from combined, weighted red color data and weighted green color data; and

more or more processors configured for outputting data corresponding to detected digital watermarking.

14. The detector apparatus of claim 13 comprising means for combining the weighted red color data and the weighted green color data by subtracting the weighted green color data from the weighted red color data.

15. The detector apparatus of claim 13 in which said means for selectively weighting aligns digital watermark detection along an a−

b direction, where a represents a first multi-color axis, and b represent a second multi-color axis.

16. A handheld device comprising the detector apparatus of claim 13.

17. A cell phone comprising the handheld device of claim 16.

18. The detector apparatus of claim 13 in which the color image data also comprises blue color data, and said means for selectively weighting the red color data and the green color data also selectively weights the blue color data so that the digital watermarking is emphasized while image content is de-emphasized when weighted red color data, weighted green color data and weighted blue color data are combined.

19. A method comprising:

obtaining data representing color image data comprising first color data and second color data, in which the first color data comprises an encoded signal including a first polarity and the second color data comprises the encoded signal including a second polarity that is inversely related to the first polarity, and in which the first color data corresponds to a first multi-color axis, and the second color data corresponds to a second multi-color axis;

combining the second color data and the first color data, said combining yielding combined image data comprising an emphasized encoded signal, in which the combined image data comprises de-emphasized image content relative to the color image data;

using one or more configured processors, analyzing the combined image data to decode a plural-bit payload from the emphasized encoded signal, said analyzing yielding the plural-bit payload; and

providing data corresponding to the plural-bit payload.

20. The method of claim 19 in which said combining aligns signal detection along an a−

b color direction in an Lab color space.

21. The method of claim 19 in which said combining provides color axis weighting with aligns signal detection along an a−

b direction in an Lab color space, where a represents the first multi-color axis, and b represent the second multi-color axis.

22. The method of claim 19 in which the encoded signal comprises digital watermarking.

23. The method of claim 19 in which said analyzing comprising signal decoding.