System and method for embedding a watermark signal that contains message data in a digital image

• US 6,792,130 B1
• Filed: 12/13/2000
• Issued: 09/14/2004
• Est. Priority Date: 12/13/2000
• Status: Active Grant

• Current Assignee: Monument Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Eastman Kodak Company
• Inventors: Jones, Paul W., Honsinger, Chris W., Rabbani, Majid
• Primary Examiner(s): Au, Amelia M.
• Assistant Examiner(s): KIM, CHONG R
• Application Number:
  US09/736,047
• Time in Patent Office: 1,371 Days
• Field of Search: 382/100, 382/271, 382/298, 380/34, 380/219, 380/220
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0085 Time domain based watermarking, e.g. watermarks spread over several images
• 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 2201/0081 whereby both original and watermarked images are required at decoder, e.g. destination-based, non-blind, non-oblivious
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking

Abstract

A method for embedding a watermark signal that contains message data in a digital image sequence having two or more frames, includes the steps of: producing a set of two or more different carrier signals from a single secure key; assigning a carrier signal from the set of carrier signals to each frame in the sequence; and embedding a watermark signal in each frame using the corresponding assigned carrier signal.

Claims

1. A method for embedding a watermark signal that contains message data in a digital image sequence having two or more frames, comprising the steps of:

a) producing a set of two or more different carrier signals;

b) assigning a carrier signal from the set of carrier signals to each frame in the sequence;

c) combining the message data with each carrier signal to produce a sequence of watermark signals;

d) embedding a watermark signal in the two or more frames of the image sequence; and

e) extracting the message data from at least one frame of a copy of the image sequence by producing a super carrier signal by summing the set of carrier signals and using the super carrier signal to extract the message data.

2. The method claimed in claim 1, wherein the carrier signals are random phase carrier images, and wherein the embedding step includes the steps of:

c1) creating a message image representing the message data;

c2) convolving the message image with each carrier image to produce a sequence of dispersed message images; and

c3) combining the dispersed message images with the respective frames of the digital image sequence.

3. The method claimed in claim 1, wherein the set of carrier signals is produced by cyclically shifting the secure key for each carrier signal.

4. The method claimed in claim 2, wherein the random phase carrier images are produced by cyclically shifting the secure key for each carrier image.

5. The method claimed in claim 2, wherein the random phase carrier images are produced by the steps of:

a1) generating a large random phase carrier image; and

a2) segmenting the large random phase carrier image into smaller random phase carrier images to produce the set of random phase carrier images.

6. The method claimed in claim 2, wherein the random phase carrier images are produced by the steps of:

a1) generating an initial random phase carrier image; and

a2) spatially transforming the initial random phase carrier image to produce the set of random phase carrier images.

7. The method claimed in claim 1, further comprising the step of extracting message data from at least one frame of the image sequence.

8. The method claimed in claim 2, further comprising the step of extracting the message image from at least one frame of the image sequence.

9. The method claimed in claim 8, wherein the message image is extracted by producing a super carrier image by summing the set of carrier images and correlating the super carrier image with the image sequence frame.

10. The method claimed in claim 1, wherein the same carrier signal is assigned to two or more consecutive frames.

11. The method claimed in claim 2, wherein the same carrier image is assigned to two or more consecutive frames.

23. A computer program embodied in a computer readable medium for performing the method of claim 1.

12. A system for embedding a watermark signal that contains message data in a digital image sequence having two or more frames, comprising:

a) means for producing a set of two or more different carrier signals from a single secure key;

b) means for assigning a carrier signal from the set of carrier signals to each frame in the sequence;

c) means for combining the message data with each carrier signal to produce a sequence of watermark signals;

d) means for embedding a watermark signal in the two or more frames of the image sequence; and

e) means for extracting the message data from at least one frame of a copy of the image sequence by producing a super carrier signal by summing the set of carrier signals and using the super carrier signal to extract the message data.

13. The system claimed in claim 12, wherein the carrier signals are random phase carrier images, and wherein the means for embedding includes:

c1) means for creating a message image representing the message data;

c2) means for convolving the message image with each carrier image to produce a sequence of dispersed message images; and

c3) means for combining the dispersed message images with the respective frames of the digital image sequence.

14. The system claimed in claim 12, wherein the set of carrier signals is produced by cyclically shifting the secure key for each carrier signal.

15. The system claimed in claim 13, wherein the set of carrier images is produced by cyclically shifting the secure key for each carrier image.

16. The system claimed in claim 13, wherein the random phase carrier images includes:

a1) means for generating a large random phase carrier image; and

a2) means for segmenting the large random phase carrier image into smaller random phase carrier images to produce the set of random phase carrier images.

17. The system claimed in claim 13, wherein the means for generating random phase carrier images includes:

a1) means for generating an initial random phase carrier image; and

a2) means for spatially transforming the initial random phase carrier image to produce the set of random phase carrier images.

18. The system claimed in claim 12, further comprising means for extracting message data from at least one frame of the image sequence.

19. The system claimed in claim 13, further comprising means for extracting the message image from at least one frame of the image sequence.

20. The system claimed in claim 19, wherein the message image is extracted by producing a super carrier image by summing the set of carrier images and correlating the super carrier image with the image sequence frame.

21. The system claimed in claim 12, wherein the same carrier signal is assigned to two or more consecutive frames.

22. The system claimed in claim 13, wherein the same carrier image is assigned to two or more consecutive frames.