Security reader for automatic detection of tampering and alteration

• US 7,259,841 B2
• Filed: 07/29/2003
• Issued: 08/21/2007
• Est. Priority Date: 10/06/1993
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Mann, Graeme R.
• Primary Examiner(s): Rosenberger; Richard A.
• Application Number:
  US10/629,172
• Publication Number:
  US 20040022420A1
• Time in Patent Office: 1,484 Days
• Field of Search: 356/71, 235/454, 235/488, 348/161, 382/115, 382/119, 382/135
• US Class Current: 356/71
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 7/10574 Multiple sources

Abstract

A document (10) is covered by a laminate (13) comprising a layer of microspheres (16) over an adhesive layer (14) covering a source image (12) such as a photograph, printed matter, or a bar code arranged on a substrate (11). Light impinging on the document (10) is split by the optical properties of the microspheres (16) and underlying specular reflectors. The remaining light passes through the microspheres (16), through the adhesive layer (14) and strikes the substrate (11) or source image (12) on the document (10), and is reflected (18) and scattered (20). Alternatively, the laminate (13) can comprise a plain or clear layer of polyester without microspheres over the adhesive layer (14). Light impinging on the laminate (13) passes through the polyester and laminate (14) to strike the substrate (11) or source image (12) where it is reflected and scattered. A first light source (24) directs light to the document (10). A second light source (26,27) directs light towards a beam splitting mirror (23) which reflects the light to the document (10). The light turning properties of the mirror (23) produce a light source which appears to an image receiver (40) as being returned from the surface of the document (10) at an angle of less than 1°. The image receiver (40) passes a signal via line (32) to a personal computer (41) which processes the received information. Such processing is to establish whether the document (10) includes a retroreflective laminate, a plain polyester laminate, or neither. Additionally, further processing can establish whether the document (10) has been tampered with, altered, or forged.

Claims

1. A method for recovering an image from a document having an image, the method comprising the steps of:

(a) providing a document having an at least partially light-transmissive first layer and a second layer located below the first layer, the second layer including at least one image;

(b) illuminating the image with a light source;

(c) recovering the image with a video image receiver to provide a source image;

(d) determining a type of the document based on the source image;

(e) illuminating the at least partially light-transmissive first layer with the light source based on the determined type of the document; and

(f) recovering a second image from the at least partially light-transmissive first layer.

2. The method of claim 1, wherein the image within the second layer comprises at least one of typewritten characters, printing, a bar code, a photograph, or handwriting.

3. The method of claim 1, wherein the light source emits light within the visible portion of the spectrum.

4. The method of claim 1, wherein the light source emits light within the infrared portion of the spectrum.

5. The method of claim 4, wherein the image within the second layer is visible to the video image receiver under infrared light.

6. The method of claim 1, wherein the light source emits light within the ultraviolet portion of the spectrum.

7. The method of claim 6, wherein the image within the second layer is visible to the video image receiver under ultraviolet light.

8. The method of claim 1, wherein the light source emits polarized light.

9. The method of claim 1, wherein the method further comprises:

(g) sending the output signal to a personal computer.

10. The method of claim 1, wherein the document is a passport or an identification card.

11. The method of claim 1, wherein illuminating the at least partially light-transmissive first layer based on the determined type of the document comprises illuminating the at least partially Iight-transmissive first layer with the light source to identify a type of the at least partially light-transrnissive first layer.

12. The method of claim 11, wherein illuminating the at least partially light-transmissive first layer to identify a type of the at least partially light-transmissive first layer comprises:

illuminating the at least partially light-transrnissive first layer with the light source at a low intensity to invoke a visual response; and

determining the type of the at least partially Iight-transmissive first layer based on the visual response.

13. The method of claim 11, further comprising comparing the identified type of the at least partially light-transmissive first layer with an expected type of the at least partially light-transinissive first layer that is associated with the type of document.

14. The method of claim 11, wherein identifing a type of the at least partially light-transmissive first layer comprises identifying the at least partially light-transmissive first layer as one of a retrorefiective laminate and a polyester laminate.

15. The method of claim 11, further comprising adjusting the intensity of the light source based on the identified type of the at least partially light-transmissive first layer to recover the second image.

16. The method of claim 1, further comprising comparing the second image to a stored reference image.

17. The method of claim 1, wherein determining a type of the document comprises decoding the source image into a computer-compatible code representative of the type of the document.

18. The method of claim 17, further comprising looking up the code in a reference table to determine an expected type of the at least partially light-transmissive first layer associated with the code.

19. The method of claim 1, wherein determining a type of the document comprises determining a country of origin of the document.

20. A method for recovering an image from a document having an image, the method comprising the steps of:

(a) providing a document having an at least partially light-transmissive first layer and a second layer located below the first layer, the second lever including at least one image;

(b) illuminating the image with a light source;

(c) recovering the image with a video image receiver to provide a source image;

(d) determining a type of the document based on the source image;

(e) identifying an expected type of the at least partially light-transmissive first layer based on the determined type of the document;

(f) illuminating the at least partially light-transmissive first layer with the light source; and

(g) determining whether an actual type of the at least partially light-transmissive first layer is the same as the expected type.

21. The method of claim 20, wherein the image within the second layer comprises at least one of typewritten characters, printing, a bar code, a photograph, or handwriting.

22. The method of claim 20, wherein the light source emits light within the visible portion of the spectrum.

23. The method of claim 20, wherein the light source emits light within the infrared portion of the spectrum.

24. The method of claim 23, wherein the image within the second layer is visible to the video image receiver under infrared light.

25. The method of claim 20, wherein the light source emits light within the ultraviolet portion of the spectrum.

26. The method of claim 25, wherein the image within the second layer is visible to the video image receiver under ultraviolet light.

27. The method of claim 20, wherein the light source emits polarized light.

28. The method of claim 20, wherein the method further comprises:

(f) sending the output signal to a personal computer.

29. The method of claim 20, wherein the document is a passport or an identification card.