Methods and Cards Employing Optical Phenomena

• US 20070211920A1
• Filed: 01/19/2007
• Published: 09/13/2007
• Est. Priority Date: 01/23/2006
• Status: Abandoned Application

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Rhoads, Geoffrey, Rodriguez, Tony
• Application Number:
  US11/625,139
• Publication Number:
  US 20070211920A1
• Time in Patent Office: Days
• US Class Current: 382/112
• CPC Class Codes: G06F 16/211 Schema design and management
• CPC Class Codes: G06F 40/106 Display of layout of documents; Previewing
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06Q 20/347 Passive cards
• CPC Class Codes: G06Q 20/388 using mutual authentication without cards, e.g. challenge-response
• CPC Class Codes: G06V 10/60 relating to illumination properties, e.g. using a reflectance or lighting model
• CPC Class Codes: G06V 20/80 Recognising image objects characterised by unique random patterns
• CPC Class Codes: G07D 7/004 using digital security elements, e.g. information coded on a magnetic thread or strip
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation
• CPC Class Codes: G07D 7/121 Apparatus characterised by sensor details
• CPC Class Codes: G07D 7/2033 Matching unique patterns, i.e. patterns that are unique to each individual paper
• CPC Class Codes: G07F 7/08 by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/0813 Specific details related to card security
• 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: G07F 7/1016 Devices or methods for securing the PIN and other transaction-data, e.g. by encryption arrangements for secret communication, see H04L9/00
• CPC Class Codes: G07F 7/125 Offline card verification
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/608 Watermarking
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/3278 using physically unclonable functions [PUF]

Abstract

Directional albedo of a particular article, such as an identity card, is measured and stored. When the article is later presented, it can be confirmed to be the same particular article by re-measuring the albedo function, and checking for correspondence against the earlier-stored data. The re-measuring can be performed through us of a handheld optical device, such as a camera-equipped cell phone. The albedo function can serve as random key data in a variety of cryptographic applications. The function can be changed during the life of the article. A variety of other features are also detailed.

Claims

1. A method that includes assessing directional albedo data relating to a first article, and determining—

by reference to said data and earlier-assessed albedo data, determining an identity of said article.

2. The method of claim 1 that includes determining—

by reference to said data and earlier-assessed albedo data relating to a second article, whether the first article is the second article.

3. The method of claim 1 that includes:

reading a machine-readable identifier from said first article;

by reference to said machine-readable identifier, identifying a set of earlier-assessed albedo data; and

checking said identified set of earlier-assessed albedo data against albedo data relating to the first article.

4. The method of claim 3 that includes capturing 2D image data from the first article, and determining therefrom both said directional albedo data, and said machine-readable identifier.

5. The method of claim 1 that includes:

for each of plural areas on the first article, sensing energy reflected therefrom in plural different directions, to determine a direction of maximum reflectance; and

by reference to data thereby gathered, identifying a reference set of earlier-stored data corresponding thereto, and thereby identifying the first article.

6. The method of claim 5 that includes sensing energy reflected from an identification document, and identifying the document.

7. A method comprising:

sensing an attribute from an object, from first and second different directions;

producing data therefrom; and

by reference to said produced data, in conjunction with earlier-stored data, making a determination concerning said object.

8. The method of claim 7 in which the object comprises several regions, and said sensing comprises sensing light reflected from one of said regions in a first, and in a second, direction.

9. The method of claim 7 that includes making a determination concerning an identification of said object.

10. The method of claim 7 that comprises sensing said attribute from an identification document.

11. A card construction for use with ID documents, the card comprising a substrate and at least one layer thereon, characterized in that a layer thereof includes a material responsive to stimulus to change an optical property thereof.

12. The card construction of claim 11 comprising plural layers, wherein at least one of said layers include quantum dots, and one of said layers includes a photoreactive material whose transmissivity is changeable by application of stimulus thereto.

13. The card construction of claim 11 wherein at least one layer includes metameric ink.

15. The card construction of claim 11 wherein said material is responsive to stimulus to change a directional profile of light reflected from a region of the card.

16. The card construction of claim 11 wherein said material is responsive to a liquid applied thereto to change an optical property thereof.

17. The card construction of claim 11 wherein said material is responsive to a stimulus applied thereto to change an index of refraction thereof.

14. (canceled)