Methods and apparatus employing multi-spectral imaging for the remote identification and sorting of objects

• US 20010032805A1
• Filed: 11/30/2000
• Published: 10/25/2001
• Est. Priority Date: 08/26/1998
• Status: Active Grant

• Current Assignee: John A. Moon, Nabil M. Lawandy
• Original Assignee: John A. Moon, Nabil M. Lawandy
• Inventors: Moon, John A., Lawandy, Nabil M.
• Granted Patent: US 6,488,155 B2
• Time in Patent Office: Days
• US Class Current: 209/3.3
• CPC Class Codes: B07C 5/3412 according to a code applied to the object which indicates a property of the object, e.g. quality class, contents or incorrect indication sorting according to size measured by light-responsive means B07C5/10; sorting according to optical properties B07C5/342; for packages B65D79/02; for information carriers G06K7/00
• CPC Class Codes: B07C 5/365 using a single separation means
• CPC Class Codes: G06K 19/06056 the marking comprising a further embedded marking, e.g. a 1D bar code with the black bars containing a smaller sized coding
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/1434 Barcodes with supplemental or add-on codes
• CPC Class Codes: Y10S 209/937 Laundry sorting
• CPC Class Codes: Y10S 209/939 Video scanning

Abstract

A multi-spectral imager and the applications of same for the marking and coding of, for example, textiles, linens, garments, documents and packages for high-speed machine identification and sortation. Specific uses include garment and textile rental operations, laundry operations, and the postal and mail sortation of documents and packages. Methods and apparatus are provided to identify items via information encoded within an applied mark, as well as a novel mark reading/decoding scheme. A method is disclosed for printing fluorescent marks on an item, such as a heat-sealable label, to generate a unique identification number or indicia, as well as a reader system for reading applied marks. The reader system includes an illumination source that excites the fluorescent marks in combination with a color sensitive device, such as a camera, which is “blind” to the illumination wavelength but which can discern the fluorescence color and a relative spatial order of the fluorescent marks, wherein the information is encoded.

Claims

1. A method for encoding information onto an article, comprising steps of:

expressing the information as a multi-digit number; and

encoding the number as a plurality of regions that are disposed in a predetermined linear sequence, wherein each region emits one of a plurality of predetermined wavelengths comprising a set of wavelengths.

2. A method as in

claim 1

, and further comprising a step of applying the plurality of regions to the article.

3. A method as in

claim 1

, and further comprising a step of applying the plurality of regions to the article by printing the plurality of regions using a plurality of different fluorescent inks.

4. A method as in

claim 1

, and further comprising a step of applying the plurality of regions to the article by printing the plurality of regions onto a label using a plurality of different fluorescent inks, and then affixing the label to the article.

5. A method as in

claim 1

, and further comprising a step of applying the plurality of regions to the article by impact printing the plurality of regions onto a label using a plurality of different fluorescent inks, and then affixing the label to the article by a thermal process.

6. A method as in

claim 1

, and further comprising steps of:

illuminating the plurality of regions with excitation light;

detecting a plurality of resulting wavelength emissions from the plurality of regions; and

decoding the number from the plurality of resulting wavelength emissions and their location in the linear sequence.

7. A method as in

claim 6

, and further comprising a step of identifying the article from the decoded number.

8. A method as in

claim 6

, and further comprising a step of controlling a path that the article takes from the decoded number.

11. A method as in

claim 8

, and further comprising steps of:

conveying the linen, textile or garment past a reader station; and

at the reader station, illuminating the plurality of regions with excitation light, detecting a plurality of resulting wavelength emissions from the plurality of regions and decoding the number from the plurality of resulting wavelength emissions and their location in the linear sequence.

12. A method as in

claim 11

, and further comprising a step of identifying the type of linen, textile or garment from the decoded number.

13. A method as in

claim 11

, and further comprising a step of controlling a path that the linen, textile or garment takes based on the decoded number.

14. A method as in

claim 11

, and further comprising a step of selecting a type of cleaning process for the linen, textile or garment based on the decoded number.

15. A method as in

claim 11

, and further comprising a step of selecting a storage location for the linen, textile or garment based on the decoded number.

9. A method for encoding information onto an article comprised of a linen, textile or garment, comprising steps of:

expressing the information as a multi-digit number;

encoding the number as a plurality of regions that are disposed in a predetermined linear sequence, wherein each region emits one of a plurality of predetermined wavelengths comprising a set of wavelengths; and

applying the plurality of regions to the article by printing the plurality of regions onto a label using a plurality of different fluorescent inks, and then affixing the label to the article.

10. A method as in

claim 9

, wherein the step of applying impact prints the plurality of regions onto the label, and then affixes the label to the article by a thermal process.

16. A label to be affixed to an object, said label comprising a plurality of regions arranged in a linear sequence, each region emitting, when exposed to light from an excitation source, one of a plurality of predetermined wavelengths, wherein information that is descriptive of at least one aspect of said object is encoded as a combination of only said emitted wavelengths and a spatial ordering of the emitted wavelengths.

17. A system for controlling the handling of articles based on encoded information placed on the articles, comprising:

a source of excitation light for illuminating an area on individual ones of the articles as the articles pass by the source, the area comprising a plurality of regions arranged in a linear sequence, each region emitting, when exposed to the excitation light, one of a plurality of predetermined wavelengths, wherein information that is descriptive of at least one aspect of said article is encoded as a combination of only said emitted wavelengths and a spatial ordering of the emitted wavelengths;

an imager that is responsive to the emitted wavelengths for outputting color image data of the area; and

a controller, having an input coupled to an output of said imager, for processing the color image data to decode the information and for directing the handling of the article based on the encoded information.

18. A system as in

claim 17

, wherein the controller selects a type of washing that the article will receive.

19. A system as in

claim 17

, wherein the controller selects a storage location for the article.

20. A system as in

claim 17

, wherein the area comprises a label having the plurality of regions applied thereto by printing with at least two different fluorescent inks.

21. A photonic ink responsive to illumination for emitting light containing a predetermined wavelength, said ink being comprised of a fluorescent pigment and a phthalate ester plasticizer carrier.

22. A photonic ink as in

claim 21

, wherein said phthalate ester plasticizer is comprised of one of diisononyl phthalate or dioctyl, dibutyl, diethyl, etc. phthalate.

23. A photonic ink as in

claim 21

, wherein said ink is a fluorescent impact printing ink comprised of 40 g/100 ml of fluorescent pigment/phthalate plasticizer.

24. A photonic ink as in

claim 21

, wherein said fluorescent pigment is comprised of a finely-ground thermoset plastic resin containing a selected fluorescent dye or an organic or an inorganic phosphorescent or fluorescent pigment.

25. A photonic ink as in

claim 21

, wherein said ink is printed onto a label to be affixed to an object, said label comprising a plurality of regions arranged in a linear sequence, each region comprising said photonic ink and emitting, when exposed to light from an excitation source, one of a plurality of predetermined wavelengths, wherein information that is descriptive of at least one aspect of said object is encoded as a combination of only said emitted wavelengths and a spatial ordering of the emitted wavelengths.

26. A label to be affixed to an object, said label comprising a plurality of regions arranged in a linear sequence, each region comprising a photonic ink and emitting, when exposed to light from an excitation source, one of a plurality of predetermined wavelengths, wherein information that is descriptive of at least one aspect of said object is encoded as a combination of only said emitted wavelengths and a spatial ordering of the emitted wavelengths, and further comprising a clear coating that is applied to said label for covering at least said plurality of regions.

27. A label as in

claim 26

, wherein said clear coating is comprised of an ultra-violet (UV) radiation curable coating.

28. A method for reading information based on emissions from an information encoded region on a substrate, comprising steps of:

illuminating the substrate;

obtaining an image of at least a portion of the substrate;

locating and orienting the encoded region in the image, the encoded region being comprised of a plurality of sub-regions;

locating and separating individual ones of the sub-regions in the image;

determining an emission wavelength of each separated sub-region; and

in accordance with a list of possible emission wavelengths and a spatial ordering of the sub-regions, decoding the encoded information.

29. A method as in

claim 28

, wherein the step of locating and orientating employs a center-of-mass and eccentricity image processing technique.

30. A method as in

claim 29

, wherein the center-of-mass and eccentricity image processing technique finds a center of mass of image pixels above a certain threshold, and then finds an orientation of a major axis around the center of mass.

31. A method as in

claim 28

, wherein the step of locating and orientating outlines and separates bright areas appearing in the image.

32. A method as in

claim 28

, wherein the step of obtaining an image obtains the image using a plurality of long-pass filters.

33. A method as in

claim 32

, and further comprising recording a location of a sub-region in a first image;

and locating a brightest part of the sub-region in successively filtered images

34. A method as in

claim 28

, wherein the step of locating and separating employs a peak finding algorithm based on a pattern recognition algorithm which looks for a characteristic four-point signature at inflection points of smoothed image data, wherein peaks are decoded and then sorted according to which peaks appear most like a typical sub-region, and further comprising a step of retaining a first n highest-scoring peaks, where n is a number of expected sub-regions.

35. A method as in

claim 28

, wherein the step of determining comprises a step of determining the color of each sub-region using a radial basis function neural network.

36. A method as in

claim 35

, wherein the substrate is comprised of a label that is affixed to an object that is subjected to wash cycles, and wherein data for the neural network is grouped according to a number of wash cycles.