PLANAR LASER ILLUMINATION AND IMAGING (PLIIM) SYSTEM EMPLOYING LASER-DIODE BASED PLANAR LASER ILLUMINATION ARRAYS AND A LINEAR ELECTRONIC IMAGE DETECTION ARRAY EMPLOYING IMAGE FORMATION OPTICS THAT OPTICALLY COMPENSATES FOR DECREASES IN THE POWER-DENSITY OF THE PLANAR LASER ILLUMINATION BEAM WITH INCREASES IN OBJECT DISTANCE DURING ILLUMINATION AND IMAGING OPERATIONS

• US 6,896,184 B2
• Filed: 11/15/2002
• Issued: 05/24/2005
• 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: Amundsen, Thomas, Naylor, Charles A., Knowles, Carl Harry, Schnee, Michael D., Tsikos, Constantine J., Dobbs, Russell Joseph, Zhu, Xiaoxum
• Primary Examiner(s): Lee, Michael G.
• Assistant Examiner(s): Kim, Ahshik
• Application Number:
  US10/299,098
• Publication Number:
  US 20030209602A1
• Time in Patent Office: 921 Days
• Field of Search: 235/462.06, 235/462.11, 235/462.2, 235/462.22, 235/462.23, 235/462.24, 235/462.32, 235/462.42, 235/454, 235/235.36
• US Class Current: 235/454
• 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

A planar laser illumination and imaging (PLIIM) based system having a linear image formation and detection module disposed in a system housing, and having image formation optics with a field of view projectable through an aperture in the housing and onto an object moving relative thereto during object illumination and imaging operations. A pair of planar laser illumination arrays (PLIAs) are disposed on the system housing. Each planar laser array (PLIA) includes a plurality of laser diodes arranged together in a linear manner. The planar laser illumination arrays are arranged in relation to the linear image formation and detection module, and produce a pair of planar laser illumination beams (PLIBs). The pair of stationary planar laser illumination beams are projected through light transmission apertures in the system housing and oriented such that the plane of the planar laser illumination beams is coplanar with the field of view of the linear image formation and detection module. Each planar laser illumination beam is focused so that the minimum beam width thereof occurs at a point which is the maximum object distance at which the PLIIM based system is designed to acquire linear images of the object. The object can be simultaneously illuminated by the planar laser illumination beams and imaged within the field of view of the linear image formation and detection module. A series of linear images of the object are sequentially detected by the linear image formation and detection module as the object moves past the housing, so that the series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of the object. By virtue of the present invention, decreases in the power density of the planar laser illumination beam incident on the object are optically compensated for due to fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the image formation optics.

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 said 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 on 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 stationary planar laser illumination beams (PLIBs), and projecting said pair of stationary PLIBs through said first and second light transmission apertures and oriented such that the plane of said PLIBs 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 PLIBs 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,

wherein each said PLIB is focused so that the minimum beam width thereof occurs at a point which is the maximum object distance at which said PLIIM-based system is designed to acquire linear images of said object, thereby compensating for decreases in the power density of said PLIB incident on said object due to the width of said PLIB increasing in length for increasing object distances away from said image formation optics.

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 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 PLIAs.

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. The 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.

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

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.

10. A planar laser illumination and imaging (PLIM) 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 PLIA including a plurality of laser diodes arranged in a linear manner and said PLIAs 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 PLIBs such that the planes of said first and second PLIBs 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 PLIBs 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;

wherein each said planar laser illumination beam is focused so that the minimum beam width thereof occurs at a point which is the maximum object distance at which said PLIIM based system is designed to acquire linear images of said object, thereby compensating for decreases in the power density of said planar laser illumination beam incident on said object due to the width of said planar laser illumination beam increasing in length for increasing object distances away from said image formation optics.

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.

12. The PLIIM-based system of claim 10, 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 10, 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 10, 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 10, wherein said system housing has a unitary construction.

16. An over-the-conveyor belt package identification system embodying the PLIIM-based system of claim 10.

17. A hand-supportable bar code symbol reading system embodying he PLIIM-based system of claim 10.

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 PLIAs 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 PLIBs such that the planes of the first and second stationary PLIBs 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 PLIBs 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; and

wherein each said PLIB is focused so that the minimum beam width thereof occurs at a point which is the maximum object distance at which said PLIIM-based system is designed to acquire linear images of said object, thereby compensating for decreases in the power density of said planar laser illumination beam incident on said object due to the width of said PLIB increasing in length for increasing object distances away from said image formation optics.

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 images;

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 mage formation and detection module, and producing first and second planar laser illumination beams (PLIBs);

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 PLIBs 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 PLIBs in a direction that is substantially coplanar therewith as said first and second PLIBs 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; and

wherein each said PLIB is focused so that the minimum beam width thereof occurs at a point which is the maximum object distance at which said PLIIM-based system is designed to acquire linear images of said object, thereby compensating for decreases in the power density of said planar laser illumination beam incident on said object due to the width of said increasing in length for increasing object distances away from said image formation optics.

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 variable 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 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 PLIBs through said first and second light transmission apertures and oriented, such that the plane of said PLIBs 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 PLIBs 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; and

wherein each said PLIB is focused so that the minimum beam width thereof occurs at a point which is the maximum object distance at which said PLIIM-based system is designed to acquire linear images of said object, thereby compensating for decreases in the power density of said PLIB incident on said object due to the width of said PLIB increasing in length for increasing object distances away from said image formation optics.

36. The 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. The 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.