Methods for producing low-visibility retroreflective visual tags

• US 20070139775A1
• Filed: 12/19/2005
• Published: 06/21/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Huang, Qingfeng, Shrader, Eric, Cheung, Patrick, Reich, James
• Granted Patent: US 7,387,393 B2
• Time in Patent Office: Days
• US Class Current: 359/515
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: G06K 2019/06225 using wavelength selection, e.g. colour code

Abstract

One embodiment of the present invention provides a process for producing a low-visibility retroreflective visual tag, which can be used to identify and/or determine the position of an object. This process involves placing an infra-red-blocking material over a retroreflective substrate to form the low-visibility retroreflective visual tag. This infra-red-blocking material is placed so as to form a pattern, which becomes visible to an infrared sensor when the low-visibility retroreflective visual tag is illuminated by an infra-red light source.

Claims

1. A method for producing a low-visibility retroreflective visual tag, comprising:

placing an infra-red-blocking material over a retroreflective substrate to form the low-visibility retroreflective visual tag;

wherein the infra-red-blocking material is placed to form a pattern, wherein the pattern becomes visible to an infrared sensor when the low-visibility retroreflective visual tag is illuminated by an infra-red light source.

2. The method of claim 1, wherein the retroreflective substrate includes:

reflective corner cubes;

or

transparent spheres with a refractive index substantially equal to 2.

3. The method of claim 1, wherein placing the infra-red-blocking material over the retroreflective substrate involves:

depositing the infra-red-blocking material onto the retroreflective substrate;

or

depositing the infra-red-blocking material onto a sheet of infra-red-transparent material and then laminating (or otherwise attaching) the sheet of infra-red-transparent material over the retroreflective substrate.

4. The method of claim 1, wherein the infra-red-blocking material can include:

an ink;

a dye;

a toner;

or

a pigment.

5. The method of claim 1,

wherein placing the infra-red-blocking material over the retroreflective substrate additionally involves placing an infra-red-transparent material over the retroreflective substrate;

wherein the infra-red-transparent material and the infra-red-blocking material have visible colors; and

wherein the resulting low-visibility retroreflective visual tag produces a visible pattern under visible light, which is different than (and is possibly uncorrelated with) an infra-red pattern which is produced by the low-visibility retroreflective visual tag under infrared light.

6. The method of claim 5, wherein the infra-red-transparent material can include:

an ink;

a dye;

a toner;

or

a pigment.

7. The method of claim 1,

wherein after the infra-red-blocking material is placed over the retroreflective substrate, the method further comprises placing an infra-red-transparent material over the low-visibility retroreflective visual tag;

wherein the infra-red-transparent material has one or more visible colors; and

wherein the infra-red-transparent material forms a standardized visible pattern which signifies a low-visibility retroreflective visual tag.

8. The method of claim 1,

wherein the retroreflective substrate is in the form of a pre-printed sheet or label, which is the size of a standard-sized sheet of paper;

wherein the retroreflective substrate is pre-printed with an “

invisible”

IR-reflective pattern; and

wherein a visible pattern can be printed using an infra-red-transparent material or in non-marked parts of the sheet, allowing users to print their content onto sheets which are pre-printed with tags which are only visible using an IR illuminator and camera.

9. The method of claim 1,

wherein the retroreflective substrate is in the form of a pre-printed sheet or label, which is the size of a standard-sized sheet of paper;

wherein the retroreflective substrate is possibly pre-printed with a pattern that is visible under infra-red light and/or a pattern that is visible under visible light; and

wherein placing the infra-red-blocking material over the retroreflective substrate, or placing an infra-red-transparent material over the retroreflective substrate, involves using a computer printer to print the infra-red-blocking material or the infra-red-transparent material onto the retroreflective substrate.

10. A method for producing a low-visibility retroreflective visual tag, comprising:

depositing a retroreflective material onto a desired object to form the low-visibility retroreflective visual tag;

wherein the retroreflective material is deposited in a pattern which becomes visible to an infrared sensor when the low-visibility retroreflective visual tag is illuminated by an infra-red light source; and

wherein the retroreflective material is substantially transparent to visible light so that the pattern is less visible under visible light.

11. The method of claim 10, wherein the desired object has an underlying visible pattern which is visible through the retroreflective material.

12. The method of claim 10, wherein the retroreflective material can include:

an ink;

a dye;

a toner;

or

a pigment.

13. A low-visibility retroreflective visual tag, which is produced by a process which involves:

placing an infra-red-blocking material over a retroreflective substrate to form the low-visibility retroreflective visual tag;

wherein the infra-red-blocking material is placed to form a pattern, wherein the pattern becomes visible to an infrared sensor when the low-visibility retroreflective visual tag is illuminated by an infra-red light source.

14. The low-visibility retroreflective visual tag of claim 13, wherein the retroreflective substrate includes:

reflective corner cubes;

or

transparent spheres with a refractive index substantially equal to 2.

15. The low-visibility retroreflective visual tag of claim 13, wherein placing the infra-red-blocking material over the retroreflective substrate involves:

depositing the infra-red-blocking material onto the retroreflective substrate;

or

depositing the infra-red-blocking material onto a sheet of infra-red-transparent material and then laminating (or otherwise attaching) the sheet of infra-red-transparent material over the retroreflective substrate.

16. The low-visibility retroreflective visual tag of claim 13, wherein the infra-red-blocking material can include:

an ink;

a dye;

a toner;

or

a pigment.

17. The low-visibility retroreflective visual tag of claim 13,

wherein placing the infra-red-blocking material over the retroreflective substrate additionally involves placing an infra-red-transparent material over the retroreflective substrate;

wherein the infra-red-transparent material and the infra-red-blocking material have visible colors; and

wherein the resulting low-visibility retroreflective visual tag produces a visible pattern under visible light, which is different than (and is possibly uncorrelated with) an infra-red pattern which is produced by the low-visibility retroreflective visual tag under infrared light.

18. The low-visibility retroreflective visual tag of claim 17, wherein the infra-red-transparent material can include:

an ink;

a dye;

a toner;

or

a pigment.

19. The low-visibility retroreflective visual tag of claim 13,

wherein after the infra-red-blocking material is placed over the retroreflective substrate, the process additionally involves placing an infra-red-transparent material over the low-visibility retroreflective visual tag;

wherein the infra-red-transparent material has one or more visible colors; and

wherein the infra-red-transparent material forms a standardized visible pattern which signifies a low-visibility retroreflective visual tag.

20. The low-visibility retroreflective visual tag of claim 13,

wherein the retroreflective substrate is in the form of a pre-printed sheet or label, which is the size of a standard-sized sheet of paper;

wherein the retroreflective substrate is pre-printed with an “

invisible”

IR-reflective pattern; and

wherein a visible pattern can be printed using an infra-red-transparent material or in non-marked parts of the sheet, allowing users to print their content onto sheets which are pre-printed with tags which are only visible using an IR illuminator and camera.

21. The low-visibility retroreflective visual tag of claim 13,

wherein the retroreflective substrate is in the form of a pre-printed sheet or label, which is the size of a standard-sized sheet of paper;

wherein the retroreflective substrate is possibly pre-printed with a pattern that is visible under infra-red light and/or a pattern that is visible under visible light; and

wherein placing the infra-red-blocking material over the retroreflective substrate, or placing an infra-red-transparent material over the retroreflective substrate, involves using a computer printer to print the infra-red-blocking material or the infra-red-transparent material onto the retroreflective substrate.

22. A low-visibility retroreflective visual tag, which is produced by a process which involves:

depositing a retroreflective material onto a desired object to form the low-visibility retroreflective visual tag;

wherein the retroreflective material is deposited in a pattern which becomes visible to an infrared sensor when the low-visibility retroreflective visual tag is illuminated by an infra-red light source; and

wherein the retroreflective material is substantially transparent to visible light so that the pattern is less visible under visible light.

23. The low-visibility retroreflective visual tag of claim 22, wherein the desired object has an underlying visible pattern which is visible through the retroreflective material.

24. The low-visibility retroreflective visual tag of claim 22, wherein the retroreflective material can include:

an ink;

a dye;

a toner;

or

a pigment.