Two-plane optical code reader for acquisition of multiple views of an object

• US 8,678,287 B2
• Filed: 12/23/2009
• Issued: 03/25/2014
• Est. Priority Date: 02/12/2008
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Olmstead, Bryan L.
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): LY, TOAN C
• Application Number:
  US12/646,829
• Publication Number:
  US 20100163628A1
• Time in Patent Office: 1,553 Days
• Field of Search: 235/462.41, 235/462.46
• US Class Current: 235/462.41
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• 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

Abstract

An optical code reader forms images of an optical code on an object. The reader comprises first and second viewing surfaces generally transverse to one another. The surfaces bound a viewing volume in which the object may be imaged. The reader also comprises a set of one or more imagers positioned on an opposite side of one or more of the first and second viewing surfaces relative to the viewing volume, and oriented and configured to capture images of the object from at least three different views. Each of the views passes through one of said first and second viewing surfaces. At least one of said views passes through the first viewing surface, and at least one of said views passes through the second viewing surface. The reader also comprises at least one mirror, off which is reflected at least one of the views.

Claims

1. A method for reading optical codes on objects as they pass through a viewing volume bounded on two generally transverse sides by respective first and second viewing surfaces, by use of a number of imagers wherein the optical codes appear at different ones of arbitrary locations and angular orientations of a variety of possible locations and angular orientations with respect to the viewing surfaces, the method comprising:

directing a plurality of views from the viewing volume onto different imager portions of the number of imagers, wherein the plurality of views includes at least first and second views, wherein the first view is reflected off at least one fixed mirror and the second view is reflected off at least one fixed mirror, wherein each of the plurality of views passes through one of the first and second viewing surfaces, wherein at least one of the plurality of views passes through the first viewing surface, wherein at least one of the plurality of views passes through the second viewing surface, wherein the number of views is at least three, wherein at least one of the views is reflected off a plurality of fixed mirrors including at least a first mirror and a second mirror, wherein the number of views is greater than the number of imagers, wherein at least one imager has first and second imager portions that employ at least some different pixel imaging elements such that the first imager portion obtains the first view and the second imager portion obtains the second view, wherein the first and second views are bilaterally symmetrical, and wherein the first and second views are operable to capture the optical codes at significantly different ones of the arbitrary locations and the angular orientations of the variety of the possible locations and angular orientations of the optical codes in the viewing volume;

forming at least one image for each of the optical codes with the number of imagers; and

processing each of the optical codes based on the at least one respective image.

2. A method according to claim 1, wherein the number of imagers is greater than one.

3. A method according to claim 1, wherein the at least one of the number of imagers forms images from multiple views simultaneously.

4. A method according to claim 3, wherein the number of imagers is two, wherein a first imager has three distinct views, each passing through the first viewing surface, and wherein a second imager has at least one view, which passes through the second viewing surface.

5. A method according to claim 3, wherein the number of imagers is two, wherein a first imager has three distinct fields of view, each passing through the first viewing surface, and wherein a second imager has three distinct fields of view, each passing through the second viewing surface.

6. A method according to claim 3, wherein the directing step comprises:

directing the first view from the viewing volume onto a first portion of a split-view imager via reflection off a first surface on a compound mirror structure; and

directing the second view from the viewing volume onto a second portion of a split-view imager via reflection off a second surface on the compound mirror structure.

7. A method according to claim 6, wherein the compound mirror structure is a monolithic piece.

8. A method according to claim 1, wherein the number of imagers is one.

9. A method according to claim 8, wherein the imager has three distinct views, two of which pass through the first viewing surface and one of which passes through the second viewing surface.

10. A method according to claim 8, wherein the imager has four distinct views, three of which pass through the first viewing surface and one of which passes through the second viewing surface.

11. A method according to claim 1, wherein the directing step comprises:

directing at least one of the plurality of views from the viewing volume along a perspective through a viewing surface onto an imager via a tortuous path reflecting off at least one mirror, thereby causing the imager to be closer to the viewing surface than if a straight path having the same perspective were utilized.

12. A method according to claim 1, wherein the processing step is performed by equipment located entirely behind one of the viewing surfaces.

13. A method according to claim 1, wherein the optical codes are one-dimensional optical codes.

14. A method according to claim 13, wherein the processing step comprises:

stitching together a first portion of at least one of the optical codes in an image formed by the first imager portion and a second portion of the at least one optical code in an image formed by the second imager portion.

15. A method according to claim 1, wherein the processing step comprises:

processing pixels of the at least one image along a virtual scan line across the image.

16. A method according to claim 15, wherein the virtual scan line is a member of a set of omnidirectional virtual scan lines.

17. A method according to claim 16, further comprising:

switching from use of the set of omnidirectional virtual scan lines to a set of more closely spaced unidirectional virtual scan lines.

18. A method according to claim 1, further comprising:

illuminating objects in the viewing volume.

19. A method according to claim 18, wherein illuminating objects in the viewing volume comprises:

illuminating a portion of the viewing volume seen in the first view at approximately the same time when the at least one imager is exposed to form a first image from the first view; and

illuminating a portion of the viewing volume seen in the second view at approximately the same time when the at least one imager is exposed to form a second image from the second view.

20. A method according to claim 1, further comprising:

focusing a total field of view for each imager through a respective lens for each such imager.

21. A method according to claim 1, wherein the plurality of views are capable of cumulatively viewing at least four sides of a six-sided polyhedron positioned within the viewing volume.

22. A method according to claim 21, wherein the plurality of views are capable of cumulatively viewing at least five sides of the six-sided polyhedron.

23. A method according to claim 1, wherein the number of imagers is two and the number of views is at least four.

24. A method according to claim 1, wherein the number of imagers is two and the number of views is six.

25. A method according to claim 1, wherein the number of imagers is at least one and the number of views is at least three.

26. A method according to claim 1, wherein the number of imagers is at least one and the number of views is at least four.

27. A method according to claim 1, wherein at least two of the number of imagers are mounted on opposite sides of a common circuit board.

28. A method according to claim 1, wherein any mirror positioned in an image path along more than one of the views is a fixed mirror.

29. A method according to claim 1, wherein the first and second imager portions are spatially nonoverlapping.

30. A method according to claim 1, wherein the first and second views have opposing directions.

31. A method according to claim 1, wherein the first and second views are oriented to capture opposing sides of the objects.

32. A method according to claim 1, wherein the first view is oriented to capture the leading side of the objects and the second view is oriented to capture the trailing side of the objects.

33. A method according to claim 1, wherein the first and second imager portions have different dimensions.

34. An optical code reader for forming images of optical codes on objects, the optical code reader comprising:

a first viewing surface;

a second viewing surface generally transverse to the first viewing surface, the first and second surfaces bounding a viewing volume in which the optical codes may be imaged, wherein the optical codes may appear at different ones of arbitrary locations and angular orientations of a variety of possible locations and angular orientations with respect to the viewing surfaces;

a number of imagers positioned on an opposite side of one or more of the first and second viewing surfaces relative to the viewing volume, the number of imagers being oriented and configured to capture images of the objects, when each object is in the viewing volume, from at least three different views including at least first and second views, wherein the first view is reflected off at least one fixed mirror and the second view is reflected off at least one fixed mirror, wherein the number of imagers is one or more imagers, wherein each of the views passes through one of the first and second viewing surfaces, wherein at least one of the views passes through the first viewing surface, wherein at least one of the views passes through the second viewing surface, wherein the number of views is greater than the number of imagers, wherein at least one imager has first and second imager portions that employ at least some different pixel imaging elements such that the first imager portion is operable to obtain the first view and the second imager portion is operable to obtain the second view, wherein the first and second views are bilaterally symmetrical, and wherein the first and second views are operable to capture the optical codes at significantly different ones of the arbitrary locations and the angular orientations of the variety of the possible locations and angular orientations of the optical codes in the viewing volume; and

a plurality of fixed mirrors including at least a first mirror and a second mirror positioned on an opposite side of one or more of the first and second viewing surfaces relative to the viewing volume, wherein at least one of the views is reflected off the plurality of fixed mirrors.

35. An optical code reader according to claim 34, wherein the number of imagers is two, wherein a first imager has three distinct views, each passing through the first viewing surface, and wherein a second imager has at least one view, which passes through the second viewing surface.

36. An optical code reader according to claim 34, wherein the number of imagers is two, wherein a first imager has three distinct fields of view, each passing through the first viewing surface, and wherein a second imager has three distinct fields of view, each passing through the second viewing surface.

37. An optical code reader according to claim 34, wherein one of the imagers is a split-view imager, and the first view from the viewing volume is directed onto the first portion of the split-view imager via reflection off a first surface on a compound mirror structure, and the second view from the viewing volume is directed onto the second portion of the split-view imager via reflection off a second surface on the compound mirror structure.

38. An optical code reader according to claim 37, wherein the compound mirror structure is a monolithic piece.

39. An optical code reader according to claim 34, wherein the number of imagers is at least one.

40. An optical code reader according to claim 34, wherein the at least one imager has three distinct views, two of which pass through the first viewing surface and one of which passes through the second viewing surface.

41. An optical code reader according to claim 39, wherein at least one of the imagers has four distinct views, three of which pass through the first viewing surface and one of which passes through the second viewing surface.

42. An optical code reader according to claim 41, wherein an optical path from of at least one of the views onto the at least one imager is via a tortuous path reflecting off at least one mirror, thereby causing the at least one imager to be closer to the viewing surface than if a straight path having the same perspective were utilized.

43. An optical code reader according to claim 34, further comprising:

a housing positioned on an opposite side of one or more of the first and second viewing surfaces relative to the viewing volume, the housing containing the number of imagers.

44. An optical code reader according to claim 43, wherein the housing comprises first and second intersecting housing portions, wherein the first housing portion borders the first viewing surface and the second housing portion borders the second viewing surface, and wherein the number of imagers is contained within either the first housing portion or the second housing portion or in an intersection thereof.

45. An optical code reader according to claim 44, wherein one of the first and second housing portions is an upper side housing portion and the other is a lower housing portion, and the first and second housing portions form a generally L-shaped structure.

46. An optical code reader according to claim 34, further comprising:

electronic circuitry connected to the number of imagers operable to decode the optical codes by processing the images of the objects.

47. An optical code reader according to claim 46, wherein the electronic circuitry is positioned entirely on an opposite side of one of the first and second viewing surfaces relative to the viewing volume.

48. An optical code reader according to claim 47, wherein the first viewing surface is a horizontal surface, and the second surface is a vertical surface, and the electronic circuitry is positioned entirely below the first viewing surface.

49. An optical code reader according to claim 34, further comprising:

a focusing lens positioned in an optical path for each imager in the number of imagers, wherein there is one separate focusing lens for each such imager.

50. An optical code reader according to claim 34, wherein the plurality of views are capable of cumulatively viewing at least four sides of a six-sided polyhedron positioned within the viewing volume.

51. An optical code reader according to claim 50, wherein the plurality of views are capable of cumulatively viewing at least five sides of the six-sided polyhedron.

52. An optical code reader according to claim 34, wherein the first and second viewing surfaces are substantially orthogonal to one another.

53. An optical code reader according to claim 34, wherein the optical code reader is bioptic.

54. An optical code reader according to claim 34, wherein each of the views reflects off the same mirror no more than once.

55. An optical code reader according to claim 34, wherein the number of imagers is two and the number of views is four.

56. An optical code reader according to claim 34, wherein the number of imagers is two and the number of views is six.

57. An optical code reader according to claim 34, wherein the number of imagers is at least one and the number of views is at least three.

58. An optical code reader according to claim 34, wherein the number of imagers is at least one and the number of views is at least four.

59. An optical code reader according to claim 34, wherein the first and second views have opposing directions.

60. An optical code reader according to claim 34, wherein the first and second views are oriented to capture opposing sides of the objects.

61. An optical code reader according to claim 34, wherein the first view is oriented to capture the leading side of the objects and the second view is oriented to capture the trailing side of the objects.

62. An optical code reader according to claim 34, wherein the first and second imager portions have different dimensions.

63. A method for reading optical codes on objects as they pass through a viewing volume bounded on two generally transverse sides by respective first and second viewing surfaces, by use of a number of imagers wherein the optical codes appear at different ones of arbitrary locations and angular orientations of a variety of possible locations and angular orientations with respect to the viewing surfaces, the method comprising:

directing a plurality of views from the viewing volume onto different imager portions of the number of imagers, wherein the plurality of views includes at least first and second views, wherein the first view is reflected off at least one fixed mirror and the second view is reflected off at least one fixed mirror, wherein each of the plurality of views passes through one of the first and second viewing surfaces, wherein at least one of the plurality of views passes through the first viewing surface, wherein at least one of the plurality of views passes through the second viewing surface, wherein the number of views is at least three, wherein at least one of the views is reflected off a plurality of fixed mirrors including at least a first mirror and a second mirror, wherein the number of views is greater than the number of imagers, wherein at least one imager has first and second imager portions that employ at least some different pixel imaging elements such that the first imager portion obtains the first view and the second imager portion obtains the second view, wherein the first and second views are oriented to capture opposing sides of the objects, and wherein the first and second views are operable to capture the optical codes at significantly different ones of the arbitrary locations and the angular orientations of the variety of the possible locations and angular orientations of the optical codes in the viewing volume;

forming at least one image for each of the optical codes with the number of imagers; and

processing each of the optical codes based on the at least one respective image.