초록 ▼

Line structures are provided for printed documents to encode plural-bit digital information. The encoded information can be decoded using suitably-equipped processing equipment and used to identify the printed documents. In one implementation the information is repeated differently in a two dimensio

Line structures are provided for printed documents to encode plural-bit digital information. The encoded information can be decoded using suitably-equipped processing equipment and used to identify the printed documents. In one implementation the information is repeated differently in a two dimensional pattern of line structures according to a key.

대표청구항 ▼

1. A banknote having a watermarked line art image formed thereon, the image formed according to a method of watermarking a line art image to convey auxiliary data, the line art image including at least one line art element having a contour, the method being characterized by spatially shifting the lo

1. A banknote having a watermarked line art image formed thereon, the image formed according to a method of watermarking a line art image to convey auxiliary data, the line art image including at least one line art element having a contour, the method being characterized by spatially shifting the location of said contour to effect a change in luminosity of at least one image region through which the element passes, the auxiliary data being detectable through the luminosity change. 2. A method of watermarking an image to convey auxiliary data, the image including at least one image region, the image region including at least one element, the method being characterized by providing ink droplets in the region while leaving spacing or dimensions of the element otherwise unchanged, the provided ink droplets changing the luminance in the region to convey the auxiliary data, and wherein the ink droplets include a diameter of approximately 3 μm. 3. A method of watermarking an image to convey auxiliary data, the image including at least one image region, the image region including at least one element, the method being characterized by providing ink droplets in the region while leaving spacing or dimensions of the element otherwise unchanged, the provided ink droplets changing the luminance in the region to convey the auxiliary data, and wherein the ink droplets are provided as a Gaussian profile. 4. A method of watermarking an image to convey auxiliary data, the image including at least one image region, the image region including at least one element, the method being characterized by providing ink droplets in the region while leaving spacing or dimensions of the element otherwise unchanged, the provided ink droplets changing the luminance in the region to convey the auxiliary data, and wherein relatively dark colored ink droplets are provided to the region to decrease the luminosity in the region. 5. A method of watermarking an image to convey auxiliary data, the image including at least one image region, the image region including at least one element, the method being characterized by providing ink droplets in the region while leaving spacing or dimensions of the element otherwise unchanged, the provided ink droplets changing the luminance in the region to convey the auxiliary data, and wherein relatively light colored ink droplets are provided to the region to increase the luminosity in the region. 6. A method of generating a machine readable code for a printed document to convey auxiliary data, the printed document to include at least one region, the region to include two dimensional pattern of line structures, the method being characterized by:providing an overt structure for geometric registration;generating auxiliary data comprising message values;mapping the message values so as to be conveyed through the two dimensional pattern of line structures; andrepeating the auxiliary data in the two dimensional pattern of line structures, wherein the repeated auxiliary data is represented differently in the two dimensional pattern of line structures according to an independent code signal. 7. The method of claim 6, wherein the code signal comprises a key. 8. The method of claim 7, wherein the document comprises a check. 9. The method of claim 7, wherein the document comprises a security document. 10. The method of claim 7, wherein the document comprises an identification document. 11. The method of claim 7, wherein the document comprises a passport. 12. The method of claim 7, further comprising printing the document so as to include the machine readable code. 13. The method of claim 6, further comprising printing the machine readable code on the document. 14. The method of claim 13, wherein the document comprises a check. 15. The method of claim 13, wherein the document comprises a banknote. 16. The method of claim 13, wherein the document comprises a passport. 17. The method of claim 13, wherein the document comprises a secur ity document. 18. The method of claim 13, wherein the document comprises an identification document. 19. A document having a machine-readable code produced in accordance with claim 6 formed thereon. 20. A method comprising printing a document that includes a machine-readable code generated in accordance with claim 6. 21. The method of claim 6, wherein the machine readable code is steganographic. 22. The method of claim 21, wherein the steganographic machine readable code comprises a digital watermark. 23. A method comprising: receiving scan data corresponding to a document that includes a machine-readable code generated in accordance with claim 6, and decoding the scan data to obtain the auxiliary data. 24. The method of claim 23, wherein the scan data is obtained through visible light scanning of the document. 25. The method of claim 6, wherein the message values comprise plural bits. 26. The method of claim 6, wherein the code signal comprises a spreading signal. 27. The method of claim 6, wherein the code signal comprises a cryptographic key. 28. The method of claim 6, wherein the repeated auxiliary data, which is represented differently in the two dimensional pattern of line structures according to an independent code signal, comprises tiling of the auxiliary data in the two dimensional pattern of line structures. 29. The method of claim 6 further comprising error correcting the message values. 30. A method of generating a machine readable code for a check, the machine readable code conveying auxiliary data, the check to include at least one region, the one region to include a two dimensional pattern of line structures, said method comprising steps of:providing a visible structure for geometric registration;generating auxiliary data comprising message values;mapping the message values so as to be conveyed through the two dimensional pattern of line structures; andrepeating the auxiliary data in the two dimensional pattern of line structures, wherein the repeated auxiliary data is represented differently in the two dimensional pattern of line structures according to a key. 31. The method of claim 30, further comprising printing the machine readable code on the check. 32. A check having a machine-readable code produced in accordance with claim 30 formed thereon. 33. A method comprising printing a check that includes a machine-readable code generated in accordance with claim 30. 34. The method of claim 30, wherein the machine readable code is steganographic. 35. The method of claim 34, wherein the steganographic machine readable code comprises a digital watermark. 36. A method comprising: receiving scan data corresponding to a check that includes a machine-readable code generated in accordance with claim 30, and decoding the scan data to obtain the auxiliary data. 37. The method of claim 36, wherein the scan data is obtained through visible light scanning of the check. 38. The method of claim 30, wherein the message values comprise plural bits. 39. The method of claim 30 further comprising error correcting the message values. 40. A method comprising:receiving artwork including a machine readable code, the artwork characterized by:an overt structure for geometric registration; anda two-dimensional pattern of line structures, wherein the machine readable code comprises auxiliary data, and wherein the auxiliary data is mapped so as to be conveyed through the two dimensional pattern of line structures, the auxiliary data being repeated in the two dimensional pattern of line structures, but represented differently in the two dimensional pattern of line structures according to a key; andprinting a document in accordance with the received artwork. 41. The method of claim 40 wherein the auxiliary data comprises error correction coding. 42. The method of claim 40, wherein the key comprises a cryptographic key. 43. The method of claim 40, wherein the auxiliary data comprises plural bits. 44. The method of claim 40, wherein the machine readable code is steganographic. 45. The method of claim 44, wherein the steganographic machine readable code comprises a digital watermark. 46. A method comprising: receiving scan data corresponding to the document printed according to claim 40, and decoding the scan data to obtain the auxiliary data. 47. The method of claim 46, wherein the scan data is obtained through visible light scanning of the document. 48. The method of claim 40, wherein the document comprises a check. 49. The method of claim 40, wherein the document comprises a banknote. 50. The method of claim 40, wherein the document comprises a passport. 51. The method of claim 40, wherein the document comprises a security document. 52. The method of claim 40, wherein the document comprises an identification document.