Detection from Two Chrominance Directions

• US 20190026853A1
• Filed: 07/20/2018
• Published: 01/24/2019
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M.
• Granted Patent: US 10,453,163 B2
• Time in Patent Office: Days
• 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 first color data and second color data, in which the first color data comprises signal encoding including a first polarity, and in which the second color data comprises the signal encoding including a second polarity that is inversely related to the first polarity, the first polarity and the second polarity offsetting luminance attributable to the signal encoding;

one or more processors programmed for;

selectively weighting the first color data and the second color data so that the signal encoding is emphasized while image content is de-emphasized when weighted first color data and weighted second color data are combined;

detecting the signal encoding from combined, weighted first color data and weighted second color data; and

outputting data corresponding to detected signal encoding.

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

3. The detector apparatus of claim 1 in which the signal encoding comprises digital watermarking, and the weighting aligns digital watermark detection along an a−

b direction, where a represents a first color axis, and b represent a second 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 first color data comprises red color data and the weighted second color data comprises green color data, in which red color data and the 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 first color data and the second color data also selectively weights the blue color data so that the signal encoding is emphasized while image content is de-emphasized when weighted first color data, weighted second color data and weighted blue color data are combined.

8. The detector apparatus of claim 7 in which the weighted first color data comprises red color data and the weighted second color data comprises green color data, and in which the red color data, the 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 signal encoding including a first polarity, and in which the second color data comprises the signal encoding 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 and the first color data, the subtracting emphasizing the signal encoding while de-emphasizing image content;

detecting the signal encoding from the combined first color data and second color data; and

outputting data corresponding to detected signal encoding.

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 the signal encoding comprises digital watermarking and 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 first color data and second color data, in which the first color data comprises signal encoding including a first polarity, and the second color data comprises the signal encoding including a second polarity that is inversely related to the first polarity;

means for weighting the first color data and the second color data so that the signal encoding is emphasized while image content is de-emphasized when weighted first color data and weighted second color data are combined, in which said means for weighting aligns encoded signal detection along a multi-axis color direction;

means for detecting the signal encoding from combined, weighted first color data and weighted second color data; and

more or more processors configured for outputting data corresponding to detected signal encoding.

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

15. The detector apparatus of claim 13 in which the signal encoding comprise digital watermarking, and said means for selectively weighting aligns digital watermark detection along an a−

b direction, in which the multi-axis color direction corresponds to an a−

b color axis in an Lab color space.

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 15 in which the image color data also comprises third color data, and said means for weighting the first color data and the second color data also weights the third color data so that the digital watermarking is emphasized while image content is de-emphasized when weighted first color data, weighted second color data and weighted third color data are combined.

25. The detector apparatus of claim 18, in which the first color data comprises red color data, and the second color data comprises green color data, and the third color data comprises blue color data.

19. A non-transitory computer readable medium comprising instructions stored thereon, that, when executed by a processor, causes the processor to perform the following:

accessing data representing color image data comprising first color data and second color data, in which the first color data comprises signal including a first polarity, and the second color data comprises the signal encoding-including a second polarity that is inversely related to the first polarity;

weighting the first color data and the second color data so that the signal encoding is emphasized while image content is de-emphasized when weighted first color data and weighted second color data are combined, in which said weighting aligns encoded signal detection along a multi-axis color direction;

decoding a plural-bit identifier from the signal encoding within the combined, weighted first color data and weighted second color data; and

providing the plural-bit identifier as an output.

20. The non-transitory computer readable medium of claim 19 further comprising instructions stored thereon, that, when executed by a processor, causes the processor to perform the following:

combining the weighted first color data and the weighted second color data by subtracting the weighted second color data from the weighted first color data.

21. The non-transitory computer readable medium of claim 19 in which the image color data further comprises third color data, and in which the weighting the first color data and the second color data also weights the third color data so that the signal encoding is emphasized while image content is de-emphasized when weighted first color data, weighted second color data and weighted third color data are combined.

22. The non-transitory computer readable medium of claim 19 in which the signal encoding comprises digital watermarking.

23. The non-transitory computer readable medium of claim 22 in which the multi-axis color direction corresponds to an a−

b color axis in an Lab color space.

24. The non-transitory computer readable medium of claim 21, in which the first color data comprises red color data, and the second color data comprises green color data, and the third color data comprises blue color data.