Plurality of scan units with scan stitching

• US 5,495,097 A
• Filed: 09/14/1993
• Issued: 02/27/1996
• Est. Priority Date: 09/14/1993
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Swartz, Jerome, Katz, Joseph
• Primary Examiner(s): Hajec, Donald T.
• Assistant Examiner(s): FILIPEK, JEFFER
• Application Number:
  US08/127,898
• Time in Patent Office: 896 Days
• Field of Search: 235/462, 235/467, 235/383
• US Class Current: 235/462.12
• CPC Class Codes: G06K 7/10633 by oscillation
• CPC Class Codes: G06K 7/10861 sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48
• CPC Class Codes: G06K 7/10871 randomly oriented data-fields, code-marks therefore, e.g. concentric circles-code
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G06K 7/1465 using several successive scans of the optical code
• CPC Class Codes: G06K 7/1491 the method including a reconstruction step, e.g. stitching two pieces of bar code together to derive the full bar code

Abstract

A scanning system has a plurality of optical scan units. Each optical scan unit includes means for emitting light toward an item bearing an indicia. Each optical scan unit also includes means for receiving light reflected from the indicia and generating signals corresponding to the intensity of the reflected light. Also provided is a central control unit which includes means for combining together signals corresponding to the signals generated by at least two of the scan units to fully decode information contained on the indicia.

Claims

1. A scanning system, comprising:

a plurality of optical scan units, each optical scan unit including means for emitting light toward an item bearing indicia and a means for receiving light reflected from the indicia and generating signals corresponding to the intensity of the reflected light, and

a central control unit including means for combining together signals corresponding to the signals generated by at least two said scan units to fully decode information contained on the indicia,

wherein one of said at least two scan units scans a portion of the indicia which is less than the entire indicia and generates a first signal corresponding to reflected light from said portion, and another of said at least two scan units scans another portion of the indicia which is less than the entire indicia and generates a second signal corresponding to reflected light from said another portion, and said first signal and said second signal are combined to fully decode the information contained on the indicia.

2. A system as recited in claim 1, further comprising:

means for storing said first signal and said second signal prior to combining said first and said second signals.

3. A system as recited in claim 1, wherein said portion of the indicia and said another portion of the indicia are scanned simultaneously.

4. A system as recited in claim 1, wherein said portion of the indicia and said another portion of the indicia are scanned during respective different time periods sequentially.

5. A scanning system according to claim 1, further comprising means for defining a space through which the item bearing an indicia will move;

wherein;

each said optical scan unit transmits signals corresponding to the generated signals and emits light along a different line of sight toward the item as it moves through said space;

said means for receiving light includes;

a charge coupled device sensor array

a first one of the optical scan units is configured to nominally scan and sense reflected light with respect to a first plane;

a second one of the optical scan units is configured to nominally scan and sense reflected light with respect to a second plane which is angularly displaced with respect to said first plane;

said central control unit is separate and spaced apart from the optical scan units and includes means for processing the signals transmitted from the optical scan units to determine the information contained in the indicia.

6. A system as in claim 5, wherein said means for defining a space comprises a conveyor carrying items to be scanned, and a bracket supporting at least some of the optical scan units, said bracket extending from a point alongside the conveyor out away from and across the conveyor.

7. A system as in claim 5, wherein (i) said conveyor is comprised of a first conveyor belt for carrying the item into said space through which the item will move, and a second conveyor belt, disposed apart from said first conveyor belt with a separation space therebetween, for carrying the item out of said space through which the item will move, and at least some of the optical scan units have a line of sight through said separation space, and (ii) said item simultaneously contacts said first conveyor belt and said second conveyor belt to move through said space.

8. A system as in claim 7, wherein said bracket extends from a point alongside the separation space and across the separation space.

9. A system as in claim 6, wherein said conveyor is comprised of a first conveyor belt for carrying the item into said space through which the item will move, and a second conveyor belt, disposed apart from said first conveyor belt with a separation therebetween, for carrying the item out of said space, said first conveyor belt and said second conveyor belt each having a respective co-planar surface on which the item is conveyed.

10. A system as in claim 5, wherein said means for emitting light comprises a light emitting diode.

11. A system as in claim 10, wherein said means for emitting light further comprises a lens for focussing the light emitted by said light emitting diode.

12. A system as in claim 5, wherein said means for processing includes means for digitizing and signals transmitted from the optical scan units.

13. A system as in claim 5, wherein said central control unit further includes means for driving said means for emitting light.

14. A system as in claim 5, wherein each said optical scan unit is configured to nominally scan and sense reflected light with respect to a plane parallel to the direction of movement of said item.

15. A system as in claim 5, wherein said plurality of optical scan units nominally scans and senses reflected light with respect to only four planes, and each said plane is parallel to the direction of movement of said item and orthogonal to the other said planes.

16. A system as in claim 5, wherein a common plane substantially perpendicular to a direction of movement of the item is impinged by each of said plurality of scan units.

22. A system as in claim 2, wherein said illuminating means is separate and spaced apart from said optical scan units.

23. A system as in claim 22, wherein said illuminating means includes at least one light emitter disposed proximate to a side of said space.

17. A scanning system, comprising:

a plurality of optical scan units, each optical scan unit including means for optically sensing variations in light reflectivity on a surface of an item bearing an indicia and generating signals responsive to sensed variations in light reflectivity,

wherein a first one of the optical scan units is oriented for optically sensing a first portion of the indicia which is less than the entire indicia and generating a first signal responsive to the sensed variations in light reflectivity of said first portion, and

a second one of the optical scan units is oriented for optically sensing a second portion of the indicia which is less than the entire indicia and generating a second signal responsive to the sensed variations in light reflectivity of said second portion;

a central control unit for processing the generated signals to determine information contained in the indicia by combining at least the first and the second signals to fully decode the information contained in the indicia.

18. A system as recited in claim 17, further comprising:

means for storing said first signal and said second signal prior to combining said at least first and said second signals.

19. A system as recited in claim 17, wherein said first optical scan unit senses said first portion of the indicia and said second optical scan unit senses said second portion of the indicia simultaneously.

20. A system as recited in claim 17, wherein said first scan unit senses said first portion of the indicia and said second scan unit senses said second portion of the indicia during respective different time periods sequentially.

21. A scanning system according to claim 17, further comprising:

means for illuminating the space; and

means for defining a space through which the item bearing the indicia will move;

wherein each said optical scan unit optically senses variations in light reflectivity on the surface of said item as the item moves through said space and includes means for transmitting said generated signals;

wherein a first one of the optical scan units is oriented for optically sensing along a first line of sight, and

a second one of the optical scan units is oriented for optically sensing along a second line of sight angularly displaced with respect to said first line of sight;

wherein said central control unit is separate and spaced apart from the first and second optical scan units and processes the signals transmitted from the optical scan units to determine the information contained in the indicia.

24. A system as in claim 21, wherein the means to illuminate comprise a light emitting diode in each optical scan unit.

25. A system as in claim 21, wherein each optical scan unit comprises a charge coupled device sensor array.

26. A system as in claim 21, wherein said central control unit includes means for digitizing and signals transmitted from the optical scan units.

27. A system as in claim 21, wherein said central control unit further includes means for driving said illuminating means.

28. A system as in claim 21, wherein each said optical scan unit is configured to nominally scan and sense reflected light with respect to a plane parallel to the direction of movement of said item.

29. A system as in claim 21, wherein said plurality of optical scan units nominally scans and senses reflected light with respect to only four planes, and each said plane is parallel to the direction of movement of said item and orthogonal to the other said planes.

30. A system as in claim 21, further comprising a conveyor for moving the item through said space.

31. A system as in claim 30, wherein (i) said conveyor is comprised of a first conveyor belt for carrying the item into said space through which the item will move, and a second conveyor belt, disposed apart from said first conveyor belt with a separation space therebetween, for carrying the item out of said space through which the item will move, and at least one of the optical scan units has a line of sight through said separation space, and (ii) said item simultaneously contacts aid first conveyor belt and said second conveyor belt to move through said space.

32. A system as in claim 31, wherein the means for defining said space through which items will move includes a bracket which supports at least some of the plurality of optical scan units and extends from a point alongside the separation space and across the separation space.

33. A system as in claim 30, wherein said conveyor is comprised of a first conveyor belt for carrying the item into said space through which the item will move, and a second conveyor belt, disposed apart from said first conveyor belt with a separation therebetween, for carrying the item out of said space, said first conveyor belt and said second conveyor belt each having a respective co-planar surface on which the item is conveyed.

34. A system as in claim 21, wherein a common plane substantially perpendicular to a direction of movement of the item is impinged by each of said plurality of scan units.

35. A method of scanning an indicia comprising:

(1) optically sensing from a first optical scan unit variations in light reflectivity of a portion of the indicia which is less than the entire indicia on a surface of an item bearing the indicia and producing first signals responsive to variations in light reflectivity sensed, and (2) optically sensing from a second optical scan unit variations in light reflectivity of another portion of the indicia which is less than the entire indicia on the surface of the item and producing second signals responsive to variations in light reflectivity sensed; and

centrally processing the produced signals by combining signals corresponding to the first and the second signals to produce a single decoded representation of information carried by the indicia so as to fully decode the information contained in the indicia.

36. A method as recited in claim 35, further comprising the step of:

storing said first signals and said second signals prior to combining signals.

37. A method as recited in claim 35, wherein said portion of the indicia and said another portion of the indicia are sensed simultaneously.

38. A method as recited in claim 35, wherein said portion of the indicia and said another portion of the indicia are sensed during respective different time periods sequentially.

39. A method of scanning an indicia according to claim 35, further comprising illuminating a scanning space and transmitting the first and second signals to a central control, and wherein:

said optical sensing is performed along a first line of sight from the first optical scan unit variations in light reflectivity on a surface of an item bearing an indicia as the item moves through the scanning space and along a second line of sight from the second optical scan unit variations in light reflectivity on a surface of the item as the item moves through the scanning space, said second line of sight is angularly displaced from said first line of sight

said central control is separate from the first and the second optical scan units; and

said processing includes processing the transmitted signals in the central control.

40. A method as in claim 39, wherein said indicia comprises a bar code.

41. A system as in claim 39, wherein said processing includes digitizing and decoding signals transmitted from the optical scan units.

42. A system as in claim 39, wherein each line of sight nominally scans and senses reflected light with respect to a plane parallel to the direction of movement of said item.

43. A method as in claim 39, wherein each said scan unit nominally scans and senses reflected light with respect to a different plane, and each said plane is parallel to the direction of movement of said item and orthogonal to the other said planes.

44. A method as in claim 39, further comprising:

concurrently with the simultaneously sensing step, optically sensing along a third line of sight from a third optical scan unit variations in light reflectivity on a surface of the item as the item moves through the scanning space and producing third signals responsive to variations in light reflectivity sensed along said third line of sight, said third line of sight being angularly displaced from said first and second lines of sight; and

transmitting said third signals to the central control;

wherein the processing step includes processing of the third signals.

45. A method as in claim 44, further comprising:

concurrently with the simultaneously sensing step, optically sensing along a fourth line of sight from a fourth optical scan unit variations in light reflectivity on a surface of the item as the item moves through the scanning space and producing fourth signals responsive to variations in light reflectivity sensed along said fourth line of sight, said fourth line of sight being angularly displaced from said first, second and third lines of sight; and

transmitting said third signals to the central control;

wherein the processing step includes processing of the fourth signals.