Method and apparatus for detecting doubles in a singulated stream of flat articles

• US 20060269102A1
• Filed: 05/02/2006
• Published: 11/30/2006
• Est. Priority Date: 05/02/2005
• Status: Active Grant

• Current Assignee: Korber Supply Chain LLC
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Carpenter, Michael D., Mampe, John J., Dunn, Morgan
• Granted Patent: US 7,809,158 B2
• Time in Patent Office: Days
• US Class Current: 382/101
• CPC Class Codes: B07C 1/04 Forming a stream from a bulk; Controlling the stream, e.g. spacing the articles
• CPC Class Codes: B65H 2553/42 Cameras
• CPC Class Codes: B65H 2553/44 Involving light guide, e.g. optical fibres
• CPC Class Codes: B65H 2701/1315 side edges, i.e. regarded in context of transport
• CPC Class Codes: B65H 2701/1916 Envelopes and articles of mail
• CPC Class Codes: B65H 7/125 sensing the double feed or separation without contacting the articles
• CPC Class Codes: G06V 10/10 Image acquisition document image scanning and transmission H04N1/00; control of digital cameras H04N23/60
• CPC Class Codes: Y10S 209/90 Sorting flat-type mail

Abstract

A system for detection of doubles in a stream of flat items such as mail pieces being conveyed on a conveyor includes an electronic imaging camera positioned to receive an image of a side face of conveyed items over a first portion of its field of view, a reflector positioned to reflect an edge view of the items to the imaging camera, which edge view is received by the imaging camera over a second portion of its field of view, and a computer that receives image data from the camera. Program logic used by the computer determines whether the image shows one item, or more than one item.

Claims

1. A system for detection of doubles in a stream of flat items being conveyed on a conveyor, comprising:

an electronic imaging camera positioned to receive an image of a side view of a conveyed item over a first region of its field of view;

a reflector positioned to reflect an edge view of the item to the imaging camera, which edge view is received by the imaging camera over a second region of its field of view, such that the first and second regions of the field of view create a composite image; and

a computer that receives composite image data from the camera and uses program logic to determine whether the composite image shows one item, or more than one item.

2. The system of claim 1, further comprising one or more light sources positioned to illuminate the side and edge views of the item imaged by the imaging camera.

3. The system of claim 1, wherein the side view and edge view are in alignment with each other such that an edge of an item visible in the front view appears at the same relative position in the edge view.

4. The system of claim 3, wherein the items are mail pieces, the side view comprises a front face on which address information is written, and the edge view comprises the bottom edge of each mail piece, and the computer further comprises means for reading the address information.

5. The system of claim 1, wherein the items are mail pieces, the side view comprises a front face on which address information is written, and the edge view comprises the bottom edge of each mail piece, and the computer further comprises means for reading the address information.

6. The system of claim 1, wherein the reflector is positioned below the item stream and directs an image of a bottom edge of each flat item at an upward angle.

7. The system of claim 1, wherein the camera is a biaxial camera comprising a first barrel directed horizontally to receive an the side view of the conveyed item, and a second barrel directed at a downward angle to receive a reflected bottom edge view of the conveyed item.

8. The system of claim 1, further comprising an aperture plate having a vertically elongated aperture therein positioned so that the camera views a passing item through the aperture, wherein the computer assembles an image of a passing item from a succession of line scan images received by the imaging camera.

9. The system of claim 8, further comprising a conveyor belt that engages the flat item on a side opposite the side imaged by the camera, and a resilient roller positioned to resiliently engage a rear surface of the conveyor belt in a manner effective to press the belt and flat item against the aperture plate.

10. A method of detecting doubles in a stream of flat items being conveyed on a conveyor, comprising:

conveying the flat items past at least one imaging camera;

using the imaging camera to create a composite image of each flat item that includes a side view of the item and edge view of the item; and

analyzing the composite image data from the camera with a computer that uses program logic to determine whether the composite image shows one item or more than one item.

11. The method of claim 10, wherein the program logic identifies lines representing item edges in the composite image and determines whether the lines indicate a single item or more than one item.

12. The method of claim 11, wherein the step of creating a composite image comprises:

capturing a series of linear images as each flat item moves past the imaging camera, each linear image including a portion of a side view of the item and a portion of a bottom view of the item, and

combining the linear images to form the composite image.

13. The method of claim 11, wherein the side view is aligned with the edge view in the composite image.

14. The method of claim 10, wherein the flat items are mail pieces, further comprising a step of diverting mail pieces for re-sorting when the composite image indicates that two or more mail pieces are passing the camera at the same time.

15. The method of claim 11, wherein the flat items comprise mail pieces and the side view includes destination information, further comprising the steps of:

analyzing the image data to decode destination information for the mail piece;

diverting mail pieces for re-sorting when the composite image indicates that two or more mail pieces are passing the camera at the same time; and

sorting a mail piece to one of plurality of destination bins based on the decoded destination information when the composite image indicates that a single mail piece is passing the camera.

16. The method of claim 11, wherein the edge view is offset from the side view, further comprising processing the composite image data using program logic to reposition the edge view to be coincident with the side view.

17. The method of claim 10, wherein the images of the side view and the edge view are provided by separate cameras.

18. The method of claim 16, wherein the images of the side view and the edge view are provided by separate cameras.

19. The method of claim 10, wherein the analyzing step further comprises determining whether one or more of multiple addresses, multiple indicium patterns, and multiple return addresses are present in the side view.

20. The method of claim 19, wherein a single destination address, indicium, and return address, and the position of the edges from the side view are used to designate a mail piece a single item even though analysis of the bottom edge indicates that multiple items are existent.