Digital Watermarking in Data Representing Color Channels

• US 20110007935A1
• Filed: 06/11/2010
• Published: 01/13/2011
• Est. Priority Date: 04/19/2000
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M., Brundage, Trent J.
• Granted Patent: US 8,027,509 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/0042 Fragile watermarking, e.g. so as to detect tampering
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• 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 1/32208 involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 1/32251 in multilevel data, e.g. greyscale or continuous tone data
• 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 1/32293 Repeating the additional information in a regular pattern
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

The present disclosure relates to digital watermarking. One claim recites a method to detect two or more different digital watermarks in media. The method includes: receiving captured imagery of the media, the captured imagery comprising a plurality of image frames; for a first image frame applying a first watermark detector to search for a first digital watermark hidden within the first image frame, in which an electronic processor is programmed as the first watermark detector; and for a second image frame applying a second, different watermark detector to search for a second, different watermark hidden within the second image frame, in which an electronic processor is programmed as the second watermark detector. Other claims and combinations are provided too.

Claims

1. A method to detect a first digital watermark embedded in printed media, wherein the printed media comprises at least first color channel, a second color channel and a third color channel, said method comprising:

receiving optically captured data associated with the printed media, the received captured data representing a blue channel, a green channel and a red channel;

first scaling the blue channel with a first factor;

second scaling a sum of the red channel and the green channel with a second factor;

subtracting the scaled sum of the red channel and the green channel from the scaled blue channel and adding a shift factor all to yield a detection signal; and

using a programmed electronic processor or electronic hardware, searching for first digital watermarking in the detection signal.

2. The method of claim 1 in which said first scaling, second scaling, subtracting and adding are related according to:

first factor*blue channel−

second factor*(red channel+green channel)+shift.

3. The method of claim 2 in which the first factor is in a range of 0.3-0.75, the second factor is in a range of 0.15-0.375, and the shift is in a color value range of 64-192.

4. The method of claim 3 in which the first factor comprises 0.5, the second factor comprises 0.25 and the shift comprises 128.

5. The method of claim 1 in which the detection signal represents chrominance characteristics.

6. The method of claim 1 in which the further comprising searching for second digital watermarking from luminance characteristics associated with the blue channel, green channel and red channel.

7. A method to detect first steganographic indicia hidden in printed media, in which the printed media comprises at least a first color channel, a second color channel and a third color channel, said method comprising:

receiving optically captured data associated with the printed media, the received optically captured data representing a blue channel, a green channel and a red channel;

combining data representing the blue channel, data representing the green channel and data representing the red channel to minimize image interference, to yield combined channel data;

shifting the combined channel data to reduce image saturation; and

using a programmed electronic processor or electronic hardware, searching for the steganographic indicia in the shifted, combined channel data.

8. The method of claim 7 in which the shifted, combined channel data represents chrominance characteristics.

9. The method of claim 7 in which the first steganographic indicia comprises a machine-readable code.

10. The method of claim 9 in which the machine-readable code comprises digital watermarking.

11. The method of claim 7 in which the steganographic indicia comprises an image or graphic.

12. A method to detect two or more different digital watermarks in media comprising:

receiving captured imagery of the media, the captured imagery comprising a plurality of image frames;

for a first image frame applying a first watermark detector to search for a first digital watermark hidden within the first image frame, in which an electronic processor is programmed as the first watermark detector; and

for a second image frame applying a second, different watermark detector to search for a second, different watermark hidden within the second image frame, in which an electronic processor is programmed as the second watermark detector.

13. The method of claim 12 in which the first image frame and the second image frame each represent same portion of the media.