Detection of out-of-phase low visibility watermarks

• US 6,763,123 B2
• Filed: 08/20/2001
• Issued: 07/13/2004
• Est. Priority Date: 05/08/1995
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Reed, Alastair M., Cattone, Jeremy
• Primary Examiner(s): Patel, Jayanti K.
• Application Number:
  US09/933,863
• Publication Number:
  US 20020067844A1
• Time in Patent Office: 1,058 Days
• Field of Search: 382/100, 382/312, 382/232, 382/250, 235/375, 375/150, 358/3.28, 380/54, 713/176
• US Class Current: 382/100
• CPC Class Codes: B42D 25/00 Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof printing processes to produce identification or security features B41M3/14
• CPC Class Codes: B42D 25/333 Watermarks
• CPC Class Codes: B42D 25/382 absorbing or reflecting infrared light
• CPC Class Codes: G06F 16/955 using information identifiers, e.g. uniform resource locators [URL]
• CPC Class Codes: G06K 19/06009 with optically detectable marking G06K19/063, G06K19/08 take precedence
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 19/18 Constructional details
• CPC Class Codes: G06K 2019/06253 for a specific application
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G06K 7/1447 extracting optical codes from image or text carrying said optical code
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/40145 Biometric identity checks
• 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: G06V 30/40 Document-oriented image-based pattern recognition
• CPC Class Codes: G07C 9/253 visually
• CPC Class Codes: G07D 7/0034 using watermarks
• CPC Class Codes: G07D 7/004 : using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G07F 17/16 : for devices exhibiting advertisements, announcements, pictures or the like
• CPC Class Codes: G07F 7/086 : by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/1008 : Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: G10L 19/018 : Audio watermarking, i.e. embedding inaudible data in the audio signal
• CPC Class Codes: G11B 20/00086 : Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00884 : involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: G11B 20/00891 : embedded in audio data
• CPC Class Codes: H04N 1/00005 : relating to image data
• CPC Class Codes: H04N 1/00037 : Detecting, i.e. determining the occurrence of a predetermined state H04N1/00031 takes precedence
• CPC Class Codes: H04N 1/00079 : remotely
• CPC Class Codes: H04N 1/32122 : in a separate device, e.g. in a memory or on a display separate from image data
• CPC Class Codes: H04N 1/32149 : Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32154 : Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3216 : using Fourier transforms
• CPC Class Codes: H04N 1/32203 : Spatial or amplitude domain methods H04N1/32309 takes precedence
• 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 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 21/23892 : 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 2201/3205 : of identification information, e.g. name or ID code H04N2201/3209 takes precedence
• CPC Class Codes: H04N 2201/3207 : of an address
• CPC Class Codes: H04N 2201/3225 : of data relating to an image, a page or a document
• CPC Class Codes: H04N 2201/3226 : of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• 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 2201/3271 : Printing or stamping
• CPC Class Codes: H04N 2201/3274 : Storage or retrieval of prestored additional information
• CPC Class Codes: H04N 2201/3284 : for error correction

Abstract

The present invention relates to detecting digital watermarks. In a preferred embodiment, media is embedded with a digital watermark component. The media includes a cyan color plane, a magenta color plane, a yellow color plane, and a black color plane. The digital watermark component is embedded in the cyan, magenta, and yellow color planes. The digital watermark component is inverted and is embedded in the black color plane. The embedded media is illuminated with infrared light, which emphasizes the black color plane. An input device captures a digital image of the illuminated media. The digital watermark component is detected from the emphasized black plane.

Claims

1. A method to detect an out-of-phase digital watermark, the out-of-phase digital watermark embedded in media, said method comprising:

illuminating the embedded media with infrared light;

capturing an image of the illuminated media; and

analyzing the captured illuminated image to detect the out-of-phase digital watermark.

2. The method according to claim 1, wherein the out-of-phase digital watermark comprises at least a first component and a second component.

3. The method according to claim 2, wherein the first component is embedded in at least a first color plane, and the second component is embedded in at least a black color plane.

4. The method according to claim 3, wherein the second component is inverted with respect to the first component.

5. The method according to claim 4, wherein said black color plane includes black ink comprising carbon.

6. The method according to claim 1, further comprising the step of shielding the media from visible light.

7. The method according to claim 1, further comprising the step of filtering visible light before said step of capturing an image.

8. A method to detect a digital watermark embedded in media, wherein the digital watermark comprises a plurality of components, with at least some of the plurality of components cooperating to reduce localized perceptibility of the digital watermark, wherein at least one of the plurality of components is printed with a material that is responsive to non-visible light, said method comprising:

exposing the media with to the non-visible light; and

detecting the at least one digital watermark component from the exposed media.

9. The method according to claim 8, wherein the digital watermark comprises an out-of-phase digital watermark.

10. The method according to claim 8, wherein the plurality of components include a plurality of colors.

11. The method according to claim 10, wherein the plurality of colors includes at least black and the at least one digital watermark component is embedded in the black color.

12. Apparatus to detect a digital watermark, wherein the digital watermark comprises a plurality of components, with at least a first component and a second component cooperating to reduce perceptibility of the digital watermark, said apparatus comprising:

an infrared illumination source to illuminate media embedded with a digital watermark; and

an input device to capture an image of the media illuminated by said infrared illumination source.

13. The apparatus according to claim 12, further comprising electronic processing circuitry to process digital watermark detecting software instructions for detecting the digital watermark in a captured image.

14. The apparatus according to claim 13, wherein said input device comprises an infrared-pass filter.

15. The apparatus according to claim 14, wherein said digital watermark comprises an out-of-phase digital watermark.

16. The apparatus according to claim 12, further comprising an opaque housing to shield at least said input device.

17. The apparatus according to claim 12, wherein said input device comprises at least one of a digital camera and a web camera.

18. Apparatus to detect an out-of-phase digital watermark embedded in media comprising:

means for illuminating the media with infrared light;

means for capturing an image of the illuminated media; and

means for analyzing the captured image to detect the out-of-phase digital watermark.

19. A method to detect a digital watermark embedded in at least a first of a plurality of color planes, said method comprising:

isolating the first color plane from the plurality of color planes; and

analyzing the isolated color plane to detect the embedded digital watermark.

20. The method according to claim 19, wherein said isolating step comprises the step of illuminating the plurality of color planes with non-visible light.

21. The method according to claim 20, wherein the digital watermark comprises an out-of-phase digital watermark.

22. The method of claim 20, wherein the digital watermark comprises a first digital watermark component in a first of the plurality of color planes;

and a second digital watermark component in a second of the plurality of color planes so as to be inverted relative to the first digital watermark component in the first color plane.

23. The method of claim 22, wherein the second digital watermark component offsets localized luminance that is attributable to the first digital watermark component when a printed object in which the digital watermark is embedded is illuminated in a visible spectrum.

24. A method to detect a digital watermark that is embedded in media including a plurality of channels, said watermark comprising a first digital watermark component embedded in a first of the plurality of channels;

and a second digital watermark component embedded in a second of the plurality of channels, wherein the second digital watermark is generally inverted relative to the first digital watermark component in the first channel, said method comprising;

illuminating the media with non-visible light;

capturing an image of the illuminated media; and

analyzing the captured image to detect the digital watermark.

25. The method of claim 24 wherein the second digital watermark component in the second of the plurality of channels is embedded so as to be spatially registered with the first digital watermark component in the first of the plurality of channels when the media is printed.

26. The method of claim 24, wherein the second digital watermark component in the second of the plurality of channels is embedded so as to cancel at least some visibly perceptible artifacts that are caused by the embedding of the first digital watermark component.

27. The method of claim 24, wherein the second digital watermark component in the second of the plurality of channels is embedded so as to cancel at least some luminance, perceptible in a visible spectrum, that is attributable to the first digital watermark component embedded in the first of the plurality of channels when both channels are printed.

28. The method of claim 24 wherein the second digital watermark component in the second of the plurality of channels is embedded so as to be spatially inverted relative to the first digital watermark component in the first channel.

29. The method of claim 28, wherein the image is captured in at least one of the visible spectrum and the infrared spectrum.

30. The method of claim 24, wherein the non-visible light comprises infrared light.

31. A method of detecting a digital watermark component embedded in media that includes a plurality of channels, the digital watermark comprising a first digital watermark component embedded in a first channel, and a second digital watermark component embedded in a second channel, wherein the second digital watermark component is embedded so as to be registered with the first digital watermark component to reduce at least some visual artifacts in a visible spectrum that are attributable to the first digital watermark component, said method comprising:

illuminating the media with non-visible light;

capturing an image of the illuminated media; and

analyzing the captured image to detect the digital watermark.

32. The method of claim 31 wherein at least one of the first channel and the second channel comprises a black channel.

33. The method of claim 32, wherein the first channel comprises a cyan channel, a magenta channel and a yellow channel, and the second channel comprises a black channel.

34. The method of claim 32, wherein the second channel comprises a cyan channel, a magenta channel and a yellow channel, and the first channel comprises a black channel.

35. The method of claim 31, wherein the second digital watermark component comprises the first digital watermark component but in an inverted form, and wherein the visual artifacts comprise a change in luminance that is attributable to the first digital watermark component when printed.

36. The method of claim 31, wherein the non-visible light comprises infrared light.