Planar laser illumination and imaging (PLIIM) systems employing laser-diode based planar laser illumination arrays and linear electronic image detection arrays

• US 7,073,718 B2
• Filed: 02/01/2002
• Issued: 07/11/2006
• Est. Priority Date: 06/07/1999
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Amundsen, Thomas, Naylor, Charles A., Knowles, Carl Harry, Schnee, Michael D., Tsikos, Constantine J., Dobbs, Russell Joseph
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US10/066,545
• Publication Number:
  US 20040065736A1
• Time in Patent Office: 1,621 Days
• Field of Search: 23546201-46247, 235/472.01, 235/472.02, 235/472.03, 235/454, 235/455, 235/494
• US Class Current: 235/472.01
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G06K 7/10554 Moving beam scanning
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10633 by oscillation
• CPC Class Codes: G06K 7/10683 Arrangement of fixed elements
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10811 Focalisation
• 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: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches

Abstract

Methods of and systems for illuminating objects using planar laser illumination beams having substantially-planar spatial distribution characteristics that extend through the field of view (FOV) of image formation and detection modules employed in such systems. Each planar laser illumination beam is produced from a planar laser illumination beam array (PLIA) comprising an plurality of planar laser illumination modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar laser illumination beam having substantially uniform power density characteristics over the entire spatial extend thereof and thus the working range of the system. Preferably, each planar laser illumination beam component is focused so that the minimum beam width thereof occurs at a point or plane which is the farthest or maximum object distance at which the system is designed to acquire images, thereby compensating for decreases in the power density of the incident planar laser illumination beam due to the fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the imaging optics. By virtue of the present invention, it is now possible to use both VLDs and high-speed CCD-type image detectors in conveyor, hand-held and hold-under type scanning applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.

Claims

1. A planar laser illumination and imaging (PLIIM) based system comprising:

a system housing having first, second and third light transmission apertures linearly aligned with and optically isolated from each other, and said third light transmission aperture being disposed between said first and second light transmission apertures;

a linear image formation and detection module disposed in system housing, and having image formation optics with a field of view projectable through said third light transmission aperture and onto an object moving relative to said first, second and third light transmission apertures during object illumination and imaging operations; and

a pair of planar laser illumination arrays (PLIAs) disposed in said system housing, each said planar laser array (PLIA) including a plurality of laser diodes arranged together in a linear manner and said planar laser illumination arrays being arranged in relation to said linear image formation and detection module, and for producing a pair of planar laser illumination beams (PLIBs), and projecting said pair of stationary planar laser illumination beams through said first and second light transmission apertures and oriented such that the plane of said planar laser illumination beams is coplanar with the field of view of said linear image formation and detection module so that the object can be simultaneously illuminated by said planar laser illumination beams and imaged within said field of view of said linear image formation and detection module,

whereby a series of linear images of said object are sequentially detected by said linear image formation and detection module as said object moves past first, second and third light transmission apertures, so that said series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of said object.

2. The PLIIM-based system of claim 1, which further comprises:

an image frame grabber for grabbing linear images formed and detected by said image linear formation and detection module,

an image data buffer for buffering said grabbed linear images;

an image processing computer operably associated with said image data buffer, for processing said buffered linear images; and

a camera control computer for controlling said linear image formation and said detection module, and said pair of planar laser illumination arrays.

3. The PLIIM-based system of claim 1, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view.

4. The PLIIM-based system of claim 1, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

5. A PLIIM-based system of claim 1, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

6. A PLIIM-based system of claim 1, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

8. An over-the-conveyor belt package identification system embodying the PLIIM-based system of claim 1.

9. A hand-supportable bar code symbol reading system embodying the PLIIM-based system of claim 1.

12. The PLIIM-based system of claim 9, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view.

13. The PLIIM-based system of claim 9, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

14. The PLIIM-based system of claim 9, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

15. A PLIIM-based system of claim 1, wherein said system housing has a unitary construction.

16. An over-the-conveyor belt package identification system embodying the PLIIM-based system of claim 9.

17. A hand-supportable bar code symbol reading system embodying the PLIIM-based system of claim 9.

7. A PLIIM-based system of claim l, wherein said system housing has a unitary construction.

10. A planar laser illumination and imaging (PLIIM) based system comprising:

a system housing having first, second and third light transmission apertures linearly aligned with and optically isolated from each other, and said third light transmission aperture being disposed between said first and second light transmission apertures;

a linear image formation and detection module, disposed in said system housing, and having a linear detection array and image forming optics with a field of view projectable through said third light transmission aperture and onto an object moving relative to said first, second, and third light transmission apertures during object illumination and imaging operations;

a stationary field of view folding mirror, disposed in said system housing, for folding the field of view of said linear image formation and detection module in a predetermined direction with respect to said third light transmission aperture;

a pair of planar laser illumination arrays (PLIAs) disposed in said system housing, each said planar laser illumination array including a plurality of laser diodes arranged in a linear manner and said planar laser illumination arrays being arranged in relation to said linear image formation and detection module, and producing a first and second planar laser illumination beams (PLIBs);

a pair of stationary planar laser beam folding mirrors disposed in said system housing, and arranged so as to fold the optical paths of said first and second planar laser illumination beams such that the planes of said first and second planar laser illumination beams are projected through said first and second light transmission apertures and oriented in a direction that is substantially coplanar with the field of view of said linear image formation and detection module so that the object can be simultaneously illuminated by said first and second planar laser illumination beams and imaged within the field of view of said linear image formation and detection module,

whereby a series of linear images of said object are sequentially detected by said linear image formation and detection module as said object moves past said first, second and third light transmission apertures, so that said series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of said object.

11. The PLIIM-based system of claim 10, which further comprises:

an image frame grabber, disposed within said system housing, for grabbing linear images formed and detected by said linear image formation and detection module,

an image data buffer, disposed within said system housing, for buffering said grabbed linear images;

an image processing computer, operably connected to said image data buffer, for processing said buffered linear images; and

a camera control computer, disposed within said system housing, for controlling said linear image formation and said detection module.

18. A planar laser illumination and imaging (PLIIM) based system comprising:

a system housing having first, second and third light transmission apertures linearly aligned with and optically isolated from each other, and said third light transmission aperture being disposed between said first and second light transmission apertures;

a linear image formation and detection module disposed in .said system housing and having a linear detection array and image forming optics with a field of view projectable through said third light transmission aperture and onto an object moving relative to said first, second and third light transmission apertures during object illumination and imaging operations;

a pair of planar laser illumination arrays (PLIAs) disposed in said system housing, each said planar laser illumination array including a plurality of laser diodes arranged together in a linear manner and said planar laser illumination arrays being arranged in relation to said linear image formation and detection module, and producing first and second planar laser illumination beams (PLIBs); and

a pair of stationary planar laser beam folding mirrors disposed in said system housing and arranged so as to fold the optical paths of said first and second planar laser illumination beams such that the planes of the first and second stationary planar laser illumination beams are projected through said first and second light transmission apertures and oriented in a direction that is coplanar with the field of view of said linear image formation and detection module so that the object can be simultaneously illuminated by said planar laser illumination beams and imaged within said field of view of said linear image formation and detection module;

whereby a series of linear images of said object are sequentially detected by said linear image formation and detection module as said object moves past said first, second and third light transmission apertures, so that said series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of said object.

19. The PLIIM-based system of claim 18, which further comprises:

an image frame grabber, disposed within said system, for grabbing linear images framed and detected by said image formation and detection module;

an image data buffer, disposed within said system housing, for buffering said grabbed linear image;

an image processing computer, operably associated therewith, for processing said buffered linear images; and

a camera control computer for controlling said linear image formation and said detection module.

20. The PLIIM-based system of claim 18, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view.

21. The PLIIM-based system of claim 18, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

22. The PLIIM-based system of claim 18, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

23. A PLIIM-based system of claim 18, wherein said system housing has a unitary construction.

24. An over-the-conveyor belt package identification system embodying the PLIIM-based system of claim 18.

25. A hand-supportable bar code symbol reading system embodying the PLIIM-based system of claim 18.

26. A planar laser illumination and imaging (PLIIM based system comprising:

a system housing having first, second and third light transmission apertures linearly aligned with and optically isolated from each other, and said third light transmission aperture being disposed between said first and second light transmission apertures;

a linear image formation and detection module disposed in said system housing and having a linear detection array and image forming optics with a field of view projectable through said third light transmission aperture and onto an object moving relative to said first, second and third light transmission apertures during object illumination and imaging operations;

a field of view (FOV) folding/sweeping mirror, disposed in said system housing, for folding and sweeping the field of view of said linear image formation and detection module over a range of predetermined directions definable with respect to said third light transmission aperture;

a pair of planar laser illumination arrays (PLIAs), disposed in said system housing, each said planar laser illumination array including a linear array of laser diodes arranged together as a laser diode module, and said planar laser illumination arrays being arranged in relation to said image formation and detection module, and producing first and second planar laser illumination beams (PLIBs); and

a pair of planar laser beam folding/sweeping mirrors, disposed on said system housing, and jointly or synchronously movable with said FOV folding/sweeping mirror, and arranged so as to fold and sweep the optical paths of the first and second planar laser illumination beams through said first and second light transmission apertures, respectively, so that the folded field of view of said linear image formation and detection module is jointly or synchronously moved with said first and second planar laser illumination beams in a direction that is substantially coplanar therewith as said first and second planar laser illumination beams are swept over a 3-region of space so that the object can be simultaneously illuminated by said planar laser illumination beams and imaged within said field of view of said linear image formation and detection module,

whereby a series of linear images of said object are sequentially detected by said linear image formation and detection module as said object moves past said first, second, and third light transmission apertures, so that said series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of said object.

27. The PLIIM-based system of claim 26, which further comprises:

an image frame grabber, disposed within said system housing, for grabbing linear images formed and detected by said image formation and detection module,

an image data buffer, disposed within said system housing, for buffering said grabbed linear images;

an image processing computer, operably associated with said image data buffer, for processing said buffered linear images; and

a camera control computer, disposed within said system housing, for controlling said linear image formation and said detection module.

28. The PLIIM-based system of claim 27, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view.

29. The PLIIM-based system of claim 27, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

30. The PLIIM-based system of claim 27, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

31. The PLIIM-based system of claim 27, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

32. A PLIIM-based system of claim 27, wherein said system housing has a unitary construction.

33. An over-the-conveyor belt package identification system embodying the PLIIM-based system of claim 27.

34. A hand-supportable bar code symbol reading system embodying the PLIIM-based system of claim 27.

35. A planar laser illumination and imaging (PLIIM) based system comprising:

a system housing having first, second and third light transmission apertures linearly aligned with and optically isolated from each other, and said third light transmission aperture being disposed between said first and second light transmission apertures;

a linear image formation and detection module disposed in said system housing, and having a linear detection array and image forming optics with a field of view projectable through said third light transmission aperture and onto an object moving relative to said first, second and third light transmission apertures, during object illumination and imaging operations; and

a pair of planar laser illumination arrays (PLIAs) disposed in said system housing, each said planar laser illumination array including a plurality of laser diodes arranged together, and said pair of planar laser illumination arrays being arranged in relation to said linear image formation and detection module, and for producing a first and second planar laser illumination beams (PLIBs) and projecting said first and second planar laser illumination beams through said first and second light transmission apertures and oriented, such that the plane of said planar laser illumination beams is coplanar with the field of view of said linear image formation and detection module so that the object can be simultaneously illuminated by said planar laser illumination beams and imaged within said field of view of said linear image formation and detection module;

an image frame grabber, disposed in said system housing, for accessing linear images from said linear image formation and detection module;

an image data buffer, disposed in said system housing, for buffering said grabbed linear images received from said image frame grabber; and

a camera control computer, disposed in said system housing, for controlling the operation of said PLIIM-based system;

whereby a series of linear images of the object can be grabbed and buffered for subsequent use in constructing two-dimensional digital images of said object as said object moves past said first, second and third light transmission apertures.

36. A PLIIM-based system of claim 35, which further comprises:

an image processing computer, operably connected to said image data buffer, for receiving and buffering said series of linear images so as to construct said two-dimensional digital images, and for carrying out image processing algorithms (e.g. bar code symbol decoding algorithms) and operators on said two-dimensional digital images.

37. The PLIIM-based system of claim 35, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view.

38. The PLIIM-based system of claim 35, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

39. The PLIIM-based system of claim 35, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

40. A PLIIM-based system of claim 35, wherein said system housing has a unitary construction.

41. An over-the-conveyor belt package identification system embodying the PLIIM-based system of claim 35.

42. A hand-supportable bar code symbol reading system embodying the PLIIM-based system of claim 35.