System and method for digital watermarking

1. A method for generating an identification document, the method comprising:

spatially modulating a spatial luminance pattern such that the spatial luminance pattern forms a first digital watermark in a spatial domain to encode a first portion of personally identifiable information of a holder of the identification document;

spatially modulating a spatial chrominance distribution such that the spatial chrominance distribution forms a second digital watermark in the same spatial domain to encode a second portion of the same personally identifiable information of the same holder of the identification document; and

after forming the first digital watermark and the second digital watermark, applying the first digital watermark and the second digital watermark to the identification document such that the second digital watermark and the first digital watermark partially overlap to occupy a common sub-region within one side of the identification document, the common sub-region being smaller than the side of the identification document.

2. The method of claim 1 , further comprising:

embedding the first portion of the personally identifiable information in the first digital watermark; and

embedding the second portion of the personally identifiable information in the second digital watermark,

wherein the first portion of personally identifiable information includes data correlatable with the second portion of personally identifiable information; and wherein the second portion of personally identifiable information includes data correlatable with the first portion of the personally identifiable information.

3. The method of claim 2 , wherein embedding the first portion further comprises integrating an integrity check of the second portion of the personally identifiable information, and

wherein embedding the second portion further comprises integrating an integrity check of the first portion of the personally identifiable information.

4. The method of claim 3 , wherein integrating an integrity check of the second portion of the personally identifiable information the integrity check comprises including a check sum, a redundancy check, or a hash, and

wherein integrating an integrity check of the first portion of the personally identifiable information comprises including a check sum, a redundancy check, or a hash.

5. The method of claim 3 , wherein integrating an integrity check of the second portion of the personally identifiable information comprises including part of the second portion of the personally identifiable information, and

wherein integrating an integrity check of the first portion of the personally identifiable information comprises including part of the first portion of the personally identifiable information.

6. The method of claim 1 , wherein applying the first and second digital watermarks comprises:

applying the first digital watermark to a first area on the identification document; and

applying the second digital watermark to a second area on the identification document, wherein the first area and the second area share the same common sub-region within the same side of the identification document, and the common sub-region is smaller than at least one of the first area and the second area.

7. The method of claim 1 , further comprising:

configuring the first and second digital watermarks to authenticate a source of the identification document.

8. The method of claim 7 , further comprising:

configuring at least one of the first digital watermark and the second digital watermark to identify an issuer of the identification document.

9. The method of claim 1 , wherein applying the first digital watermark and the second digital watermark to the identification document comprises:

applying the first digital watermark and the second digital watermark to different grating structures underneath a same page of the identification document such that detection of the first and second digital watermarks is viewing-angle dependent or viewing-direction dependent.

10. The method of claim 1 , wherein the first portion of personally identifiable information includes first data, and the second portion of personally identifiable information include second data, and

wherein the first data and the second data are combinable to reveal a piece of the personally identification information of the holder, each of the first data and the second data partially revealing the piece of the personally identification information.

11. A computer system for generating an identification document, the computer system comprising:

at least one processor; and

at least one non-transitory computer-readable storage medium coupled to the at least one processor having instructions stored thereon that, when executed by the at least one processor, cause the at least one processor to perform operations comprising:

spatially modulating a spatial luminance pattern such that the spatial luminance pattern forms a first digital watermark in a spatial domain to encode a first portion of personally identifiable information of a holder of the identification document;

spatially modulating a spatial chrominance distribution such that the spatial chrominance distribution forms a second digital watermark in the same spatial domain to encode a second portion of the same personally identifiable information of the same holder of the identification document; and

after forming the first digital watermark and the second digital watermark, applying the first digital watermark and the second digital watermark to the identification document such that the second digital watermark and the first digital watermark partially overlap to occupy a common sub-region within one side of the identification document, the common sub-region being smaller than the side of the identification document.

12. The computer system of claim 11 , wherein the operations further comprise:

embedding the first portion of personally identifiable information in the first digital watermark and embedding the second portion of personally identifiable information in the second digital watermark, wherein the first portion of personally identifiable information includes data correlatable with the second portion of personally identifiable information; and wherein the second portion of personally identifiable information includes data correlatable with the first portion of the personally identifiable information.

13. The computer system of claim 12 , wherein the operations further comprise:

integrating, in the first portion, an integrity check of the second portion of personally identifiable information, and

integrating, in the second portion, an integrity check of the first portion of the personally identifiable information.

14. The computer system of claim 13 , wherein the operations further comprise:

integrating, in the first portion, a check sum, a redundancy check, or a hash of the second portion of personally identifiable information; and

integrating, in the second portion, a check sum, a redundancy check, or a hash of the first portion of personally identifiable information.

15. The computer system of claim 11 , wherein the operations further comprise:

integrating an integrity check of the second portion of the personally identifiable information by including part of the second portion of the personally identifiable information, and

integrating an integrity check of the first portion of the personally identifiable information by including part of the first portion of the personally identifiable information.

16. The computer system of claim 11 , wherein the operations further comprise embedding the first and second digital watermarks by:

applying the first digital watermark to a first area on the identification document; and

applying the second digital watermark to a second area on the identification document, wherein the first area and the second area share the same common sub-region within the same side of the identification document, and the common sub-region is smaller than at least one of the first area and the second area.

17. The computer system of claim 11 , wherein the operations further comprise adapting the first and second digital watermarks to authenticate a source of the identification document.

18. The computer system of claim 17 , wherein the operations further comprise adapting at least one of the first digital watermark and the second digital watermark to identify an issuer of the identification document.

19. The computer system of claim 11 , wherein the first portion of personally identifiable information includes first data, and the second portion of personally identifiable information include second data, and

wherein the first data and the second data are combinable to reveal a piece of the personally identification information of the holder, each of the first data and the second data partially revealing the piece of the personally identification information.

20. A non-transitory computer-readable medium comprising software instructions that when executed by one or more processors, cause the one or more processors to perform operations comprising:

spatially modulating a spatial luminance pattern such that the spatial luminance pattern forms a first digital watermark in a spatial domain to encode a first portion of personally identifiable information of a holder of an identification document;

spatially modulating a spatial chrominance distribution such that the spatial chrominance distribution forms a second digital watermark in the same spatial domain to encode a second portion of the same personally identifiable information of the same holder of the identification document; and

after forming the first digital watermark and the second digital watermark, applying the first digital watermark and the second digital watermark to the identification document such that the second digital watermark and the first digital watermark partially overlap to occupy a common sub-region within one side of the identification document, the common sub-region being smaller than the side of the identification document.