System, method, and product for distortion-compensated information embedding using an ensemble of non-intersecting embedding generators

• US 6,400,826 B1
• Filed: 04/27/1999
• Issued: 06/04/2002
• Est. Priority Date: 05/21/1998
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Chen, Brian, Wornell, Gregory W.
• Primary Examiner(s): Johns, Andrew W.
• Assistant Examiner(s): NAKHJAVAN, SHERVIN K
• Application Number:
  US09/300,643
• Time in Patent Office: 1,134 Days
• Field of Search: 382/100, 382/232, 382/248, 382/251, 382/276, 380/200, 380/205, 380/209, 380/210, 380/252, 380/253, 380/255, 380/257, 380/41, 380/758, 380/287, 283/72, 283/73, 283/113, 283/114, 713/150, 713/151, 713/168, 713/187, 713/189, 370/527, 370/529
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• 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: H04H 20/31 using in-band signals, e.g. subsonic or cue signal
• CPC Class Codes: H04H 2201/50 characterised by the use of watermarks
• 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

Abstract

A system, method, and product provide distortion compensation when watermarking a host signal with a watemark signal. The watermark signal includes watermark-signal components having watermark-signal values, and the host signal includes host-signal components having host-signal values. A system includes an ensemble designator that designates a plurality of embedding generators, each corresponding to a single watermark-signal value of a co-processed group of one or more watermark-signal components. Also included is an embedding value generator that generates embedding values by each embedding generator. The system also has a point coder that sets at least one host-signal value of one or more selected host-signal components to a first embedding value to form a composite-signal value. A distortion compensator modifies at least one composite signal value. The distortion compensator includes a difference signal generator that generates a difference signal component having a first difference-signal value that is the difference between a host-signal value and its corresponding composite-signal value. The distortion compensator also includes a difference signal processor that scales the difference-signal value by a scaling factor, A distortion compensation combiner then generates a distortion-compensated composite signal based on the scaled difference-signal value and the composite-signal value. The distortion compensator may modify the composite signal value based on the number of possible watermark signal values to be embedded, a watermark-induced distortion level, an expected channel-induced distortion level, and a reliability of extracting the watermark signal.

Claims

1. A system that watermarks a host signal with a watermark signal, the watermark signal comprising watermark-signal components, each having one of a plurality of watermark-signal values, and the host signal comprising host-signal components, each having one of a plurality of host-signal values, the system comprising:

an ensemble designator that designates a plurality of embedding generators, each corresponding to a single watermark-signal value of a co-processed group of one or more watermark-signal components;

an embedding value generator that generates, by each embedding generator, a plurality of embedding values, the total of each plurality of embedding values comprising a first embedding-value set, wherein at least one embedding value generated by a first embedding generator is not the same as any embedding value generated by a second embedding generator;

a point coder that sets at least one host-signal value of one or more selected host-signal components to a first embedding value of a third embedding generator, thereby forming a composite-signal value, wherein the third embedding generator corresponds to a first watermark-signal value of the group of co-processed watermark-signal components, and wherein at least one embedding interval of one embedding generator is not the same as any embedding interval of at least one other embedding generator; and

a distortion compensator that modifies at least one composite signal value, thereby forming a distortion-compensated composite signal value of a distortion-compensated composite signal component, wherein the distortion-compensated composite signal value has a distortion with respect to the at least one host signal value that is less than a distortion of the at least one composite signal value with respect to the at least one host signal value.

2. The system of claim 1, further comprising:

a pre-processor that operates on one or more primary-signal components of at least one primary signal to generate one or more transformed host-signal components and one or more transformed watermark-signal components, wherein the ensemble designator designates a plurality of embedding generators, each corresponding to a single transformed watermark-signal value of a co-processed group of one or more transformed watermark-signal components, and wherein the point coder sets at least one host-signal value of one or more selected transformed host-signal components to the first embedding value of the third embedding generator, thereby forming the composite-signal value, and wherein the third embedding generator corresponds to a first watermark-signal value of the group of co-processed transformed watermark-signal components.

3. The system of claim 1, further comprising:

a pre-processor that operates on one or more primary-signal components of at least one primary signal and one or more supplemental-signal components of a supplemental signal to generate one or more transformed host-signal components, wherein the point coder sets at least one host-signal value of one or more selected transformed host-signal components to the first embedding value of the third embedding generator, thereby forming the composite-signal value.

4. The system of claim 1, further comprising:

an information extractor that extracts the first watermark-signal value from the first embedding value.

5. The system of claim 4, wherein the information extractor comprises:

a synchronizer that acquires a composite signal including the distortion-compensated composite-signal value;

an ensemble replicator that replicates the first embedding-value set to form a second embedding-value set, each embedding value of the second embedding-value set having the same correspondence to a single watermark-signal value as has the one embedding value of the first embedding-value set from which it is replicated;

a point decoder that selects a second embedding value of the second embedding-value set based on its proximity to the distortion-compensated composite-signal value, and that sets the first watermark-signal value to a one of the plurality of watermark-signal values to which the second embedding value corresponds.

6. The system of claim 4, wherein the information extractor comprises:

a synchronizer that acquires a composite signal including the distortion-compensated composite-signal value;

an ensemble replicator that replicates a first distortion-compensated embedding-value set to form a second distortion-compensated embedding-value set, each embedding value of the second distortion-compensated embedding-value set having the same correspondence to a single watermark-signal value as has the one embedding value of the first distortion-compensated embedding-value set from which it is replicated;

a point decoder that selects a second embedding value of the second distortion-compensated embedding-value set based on its proximity to the distortion-compensated composite-signal value, and that sets the first watermark-signal value to a one of the plurality of watermark-signal values to which the second embedding value corresponds.

7. The system of claim 1, further comprising:

a conventional embedder that embeds at least one of the group of co-processed watermark-signal components into the distortion-compensated composite signal component.

8. The system of claim 1, further comprising:

a block selector that selects one or more host-signal components for embedding.

9. The system of claim 8, wherein:

the block selector selects the one or more host-signal components for embedding based upon a masking characteristic of the host signal.

10. The system of claim 1, wherein:

the plurality of embedding generators designated by the ensemble designator comprise a plurality of adaptive embedding generators, each corresponding to a single watermark-signal value of a co-processed group of one or more watermark-signal components;

the embedding value generator comprises an adaptive embedding value generator that generates, by each adaptive embedding generator, a plurality of adaptive embedding values, the total of each plurality of embedding values comprising a first embedding-value set comprising a plurality of embedding super-groups, wherein at least one embedding value generated by a first embedding generator is not the same as any embedding value generated by a second embedding generator; and

the point coder sets at least one host-signal value of one or more selected host-signal components to a first embedding value of a third embedding generator, thereby forming a composite-signal value, wherein the first embedding value is selected based at least in part on its being the furthest in a first embedding super-group from the host-signal value, wherein the first super-group comprises a plurality of embedding values of the third embedding generator that are each closer to the host-signal value than any other embedding value of the third embedding generator, wherein the third embedding generator corresponds to a first watermark-signal value of the group of co-processed watermark-signal components.

11. The system of claim 1, wherein:

the distortion compensator modifies the at least one composite signal value based on a number of possible watermark signal values to be embedded, a watermark-induced distortion level, an expected channel-induced distortion level, and a reliability of extracting the watermark signal.

12. The system of claim 1, wherein:

the distortion compensator comprises

a difference signal generator constructed and arranged to generate at least a first difference signal component having a first difference-signal value that comprises a difference between a first host-signal value of a first of the one or more selected host signal components and its corresponding first composite-signal value.

13. The system of claim 12, wherein:

the distortion compensator further comprises

a difference signal processor constructed and arranged to scale the first differense-signal value by a first scaling factor.

14. The system of claim 13, wherein:

the difference signal generator further is constructed and arranged to generate a second difference signal component having a second difference-signal value that comprises a difference between a second host-signal value of a second of the one or more selected host signal components and its corresponding composite-signal value, and

the difference signal processor further is constructed and arranged to scale the second difference-signal value by a second scaling factor that is different than the first scaling factor.

15. The system of claim 13, wherein:

the difference signal generator further is constructed and arranged to generate a second difference signal component having a second difference-signal value that comprises a difference between a second host-signal value of a second of the one or more selected host signal components and its corresponding composite-signal value, and

the first scaling factor is based, at least in part, on the second difference-signal value.

16. The system of claim 13, wherein:

the first scaling factor is based, at least in part, on the first host-signal value.

17. The system of claim 13, wherein:

the distortion compensator further comprises

a distortion compensation combiner constructed and arranged to generate at least a first distortion-compensated composite signal based on the scaled first difference-signal value and the first composite-signal value.

18. The system of claim 17, wherein:

the distortion compensation combiner is constructed and arranged to generate the first distortion-compensated composite signal by adding the scaled first difference-signal value and the first composite-signal value.

19. The system of claim 13, wherein:

the distortion compensator further comprises

a distortion compensation combiner constructed and arranged to generate at least a first distortion-compensated composite signal based on the scaled first difference-signal value, the first composite-signal value, and the first host-signal value.

20. The system of claim 13, wherein:

the distortion compensator further comprises

a distortion compensation combiner constructed and arranged to generate at least a first distortion-compensated composite signal based on the scaled first difference-signal value, the first composite-signal value, and at least one host-signal value of the host-signal components of the host signal.

21. The system of claim 20, wherein:

the first distortion-compensated composite signal is based on at least one perceptual masking property of at least one host-signal component.

22. The system of claim 1, wherein:

the distortion compensator comprises

a difference signal generator constructed and arranged to generate at least a first difference signal component having a first difference-signal value that comprises a filtered difference between a first host-signal value of a first of the one or more selected host signal components and its corresponding composite-signal value.

23. The system of claim 22, wherein:

the difference between the first host-signal value of the first of the one or more selected host signal components and its corresponding composite-signal value is filtered based on at least one perceptual masking property of at least one host-signal component.

24. The system of claim 23, wherein:

the difference between the first host-signal value of the first of the one or more selected host signal components and its corresponding composite-signal value is filtered using a Fourier transform.

25. A method for watermarking a host signal with a watermark signal, the watermark signal comprising watermark-signal components, each having one of a plurality of watermark-signal values, and the host signal comprising host-signal components, each having one of a plurality of host-signal values, the method comprising the steps of:

(1) designating a plurality of embedding generators, each corresponding to a single watermark-signal value of a co-processed group of one or more watermark-signal components;

(2) generating, by each embedding generator, a plurality of embedding values, the total of each plurality of embedding values comprising a first embedding-value set, wherein at least one embedding value generated by a first embedding generator is not the same as any embedding value generated by a second embedding generator;

(3) setting at least one host-signal value of one or more selected host-signal components to a first embedding value of a third embedding generator, thereby forming a composite-signal value, wherein the third embedding generator corresponds to a first watermark-signal value of the group of co-processed watermark-signal components, and wherein at least one embedding interval of one embedding generator is not the same as any embedding interval of at least one other embedding generator; and

(4) modifying at least one composite signal value, thereby forming a distortion-compensated composite signal value of a distortion-compensated composite signal component, wherein the distortion-compensated composite signal value has a distortion with respect to the at least one host signal value that is less than a distortion of the at least one composite signal value with respect to the at least one host signal value.

26. The method of claim 25, wherein:

step (4) includes the step of generating at least a first difference signal component having a first difference-signal value that comprises a difference between a first host-signal value of a first of the one or more selected host signal components and its corresponding first composite-signal value.

27. The method of claim 26, wherein:

step (4) further includes the step of scaling the first difference-signal value by a first scaling factor.

28. The method of claim 27, wherein:

step (4) includes the steps of

generating a second difference signal component having a second differense-signal value that comprises a difference between a second host-signal value of a second of the one or more selected host signal components and its corresponding composite-signal value, and

scaling the second difference-signal value by a second scaling factor that is different than the first scaling factor.

29. The method of claim 27, wherein:

step (4) includes the steps of generating a second difference signal component having a second difference-signal value that comprises a difference between a second host-signal value of a second of the one or more selected host signal components and its corresponding composite-signal value, wherein the first scaling factor is based, at least in part, on the second difference-signal value.

30. The method of claim 27, wherein:

the first scaling factor is based, at least in part, on the first host-signal value.

31. The method of claim 27, wherein:

step (4) also includes the step of generating at least a first distortion-compensated composite signal based on the scaled first difference-signal value and the first composite-signal value.

32. The method of claim 31, wherein:

the step of generating at least a first distortion-compensated composite signal includes adding the scaled first difference-signal value and the first composite-signal value.

33. The method of claim 27, wherein:

step (4) also includes the step of generating at least a first distortion-compensated composite signal based on the scaled first difference-signal value, the first composite-signal value, and the first host-signal value.

34. The method of claim 27, wherein:

step (4) also includes the step of generating at least a first distortion-compensated composite signal based on the scaled first difference-signal value, the first composite-signal value, and at least one host-signal value of the host-signal components of the host signal.

35. The method of claim 34, wherein:

the step of generating at least a first distortion-compensated composite signal includes basing it on at least one perceptual masking property of at least one host-signal component.

36. The method of claim 25, wherein:

step (4) includes the step of generating at least a first difference signal component having a first difference-signal value that comprises a filtered difference between a first host-signal value of a first of the one or more selected host signal components and its corresponding composite-signal value.

37. The method of claim 31, wherein:

the filtering of the difference between the first host-signal value of the first of the one or more selected host signal components and its corresponding composite-signal value based on at least one perceptual masking property of at least one host-signal component.

38. The method of claim 37, wherein:

the filtering of the difference between the first host-signal value of the first of the one or more selected host signal components and its corresponding composite-signal value is done using a Fourier transform.

39. A computer program product comprising storage media that contains software that, when executed on a computing system, performs a method for watermarking a host signal with a watermark signal, the watermark signal comprising watermark-signal components, each having one of a plurality of watermark-signal values, and the host signal comprising host-signal components, each having one of a plurality of host-signal values, the method comprising the steps of:

(1) designating a plurality of embedding generators, each corresponding to a single watermark-signal value of a co-processed group of one or more watermark-signal components;

(2) generating, by each embedding generator, a plurality of embedding values, the total of each plurality of embedding values comprising a first embedding-value set, wherein at least one embedding value generated by a first embedding generator is not the same as any embedding value generated by a second embedding generator;

(3) setting at least one host-signal value of one or more selected host-signal components to a first embedding value of a third embedding generator, thereby forming a composite-signal value, wherein the third embedding generator corresponds to a first watermark-signal value of the group of co-processed watermark-signal components, and wherein at least one embedding interval of one embedding generator is not the same as any embedding interval of at least one other embedding generator; and

(4) modifying at least one composite signal value, thereby forming a distortion-compensated composite signal value of a distortion-compensated composite signal component, wherein the distortion-compensated composite signal value has a distortion with respect to the at least one host signal value that is less than a distortion of the at least one composite signal value with respect to the at least one host signal value.

40. The computer program product of claim 39, wherein:

step (4) includes the step of generating at least a first difference signal component having a first difference-signal value that comprises a difference between a first host-signal value of a first of the one or more selected host signal components and its corresponding first composite-signal value.

41. The computer program product of claim 40, wherein:

step (4) further includes the step of scaling the first difference-signal value by a first scaling factor.

42. The computer program product of claim 41, wherein:

step (4) also includes the step of generating at least a first distortion-compensated composite signal based on the scaled first difference-signal value and the first composite-signal value.

43. The computer program product of claim 42, wherein:

the step of generating at least a first distortion-compensated composite signal includes adding the scaled first difference-signal value and the first composite-signal value.

44. The computer program product of claim 41, wherein:

step (4) also includes the step of generating at least a first distortion-compensated composite signal based on the scaled first difference-signal value, the first composite-signal value, and the first host-signal value.

45. The computer program product of claim 39, wherein:

step (4) includes the step of generating at least a first difference signal component having a first difference-signal value that comprises a filtered difference between a first host-signal value of a first of the one or more selected host signal components and its corresponding composite-signal value.