Hand-supportable planar laser illumination and imaging (PLIIM) device

• US 6,948,659 B2
• Filed: 03/22/2002
• Issued: 09/27/2005
• 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: Good, Timothy A., Knowles, C. Harry, Schnee, Michael D., Tsikos, Constantine J.
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US10/105,031
• Publication Number:
  US 20030035461A1
• Time in Patent Office: 1,285 Days
• Field of Search: 23546201-46245, 235/472.01, 235/472.02, 235/472.03, 235/454, 235/455, 235/470, 235/494
• US Class Current: 235/462.01
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 19/0085 for use with both a detector and a source , e.g. in a transceiver, G02B19/009, G02B19/0095 take precedence
• CPC Class Codes: G02B 19/009 for use with infrared radiation
• CPC Class Codes: G02B 19/0095 for use with ultraviolet radiation
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 27/095 Refractive optical elements
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/146 the method including quality enhancement steps
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: G06Q 30/00 Commerce
• CPC Class Codes: G06V 20/62 Text, e.g. of license plates, overlay texts or captions on TV images
• CPC Class Codes: G06V 30/144 using a slot moved over the image; using discrete sensing elements at predetermined points; using automatic curve following means
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/02325 Mechanically integrated components on mount members or optical micro-benches
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence

Abstract

A hand-supportable linear-type planar laser illumination and imaging (PLIIM) based device comprising a linear image formation and detection (IFD) module having a linear array of image detection elements and also image formation optics having a field of view (FOV) focusing a linear image of an object onto the linear array of image detection elements. A pair of planar laser illumination arrays (PLIAs) is arranged on opposite sides of the linear image formation and detection module, and produces a plurality of spatially-incoherent planar laser illumination beam (PLIB) components that are optically combined with respect to other PLIB components so as to produce a composite planar laser illumination beam (PLIB) that is arranged in a coplanar relationship with at least a portion of the FOV. Each PLIA includes a plurality of planar laser illumination modules (PLIMs). Each PLIM includes a laser diode and beam focusing and diverging optics for producing one spatially-incoherent PLIB component. The composite PLIB produces a number of substantially different individual speckle noise patterns at the linear array of image detection elements during the photo-integration time period thereof. The speckle noise power observed at the linear array of image detection elements is reduced through temporal averaging of the individual speckle noise patterns during the photo-integration time period. By virtue of the present invention, it is now possible to use visible laser diodes (VLDs) to produce speckle-reduced images of objects suitable for OCR processing, while enjoying improved working distances offered by planar laser illumination techniques.

Claims

1. A hand-supportable linear-type planar laser illumination and imaging (PLIIM) based device, comprising:

a hand-supportable housing having a light transmission aperture;

a support platform mounted within said hand-supportable housing;

a linear image formation and detection (IFD) module mounted on said support platform, and having a linear array of image detection elements and also image formation optics having a field of view (FOV) projectable through said light transmission aperature and into an illumination and imaging field, definable external to said hand-supportable housing, and in which an object can be presented for illumination and imaging, and said FOV focusing a linear image of said object onto said linear array of image detection elements; and

a pair of planar laser illumination arrays (PLIAs) aranged on opposite sides of said linear IFD module, and mounted on said support platform;

wherein said pair of PLIAs produces a plurality spatially-incoherent planar laser illumination beam (PLIB) components that are optically combined with respect to other said PLIB components so as to produce a composite planar laser illumintaion beam (PLIB) that is spatially aligned with respect to said FOV and arranged in a co-planar relationship with at least a portion of said FOV;

wherein each said PLIA includes a plurality of planar laser illumination modules (PLIMs),

wherein each said PLIM includes a laser diode and beam focusing and diverging optics for producing one said spatially-incoherent PLIB component;

wherein said composite PLIB produces a number of substantially different individual speckle noise patterns at said linear array of image detection elements during the photo-integration time period thereof;

wherein the level of speckle noise power observed at said linear array of image detection elements is reduced through temporal averaging of said substantially different individual speckle noise patterns at said linear array of image detection elements during said photo-integration time period.

2. The hand-supportable PLIIM based device of claim 1, wherein a series of linear images of said object are sequentially detected by said linear IFD module as said object relatively moves past said linear IFD module, so that said series of linear images can be grabbed and buffered within said hand-supportable housing for subsequent use in constructing two-dimensional images of said object.

3. The hand-supportable PLIIM based device of claim 1, wherein each said laser diode is a visible laser diode (VLD).

4. The hand-supportable PLIIM based device of claim 1, wherein each said beam focusing and diverging optics comprises a focusing lens and a cylindrical lens.

5. The hand-supportable PLIIM based device of claim 1, which further comprises:

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

an image data buffer for buffering said grabbed linear images to form a two-dimensional image.

6. The hand-supportable PLIIM based device of claim 5, which further comprises:

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 IFD module, and said pair of planar laser illumination arrays.

7. The hand-supportable PLIIM based device of claim 1, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).

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

9. The hand-supportable PLIIM based device of claim 1, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

10. The hand-supportable PLIIM based device of claim 1, which further comprises a field of view (FOV) folding mirror for folding said FOV onto said linear array of image detection elements.

11. The hand-supportable PLIIM based device of claim 1, wherein said FOV folding mirror is mounted on said support platform.

12. The hand-supportable PLIIM based device of claim 1, which further comprises a planar laser illumination beam (PLIB) folding mirror for folding said composite PLIB towards said illumination and imaging field.

13. The hand-supportable PLIIM based device of claim 1, which further comprises

a field of view (FOV) folding mirror for folding said FOV onto said linear array of image detection elements, and

a planar laser illumination beam (PLIB) folding mirror for folding said composite PLIB towards said illumination and imaging field.

14. The hand-supportable PLIIM based device of claim 13, which further comprises a PLIB/FOV sweeping mechanism for sweeping said PLIB and coplanar FOV across a 3-D illumination and imaging field external to said hand-supportable housing.

15. A linear-type planar laser illumination and imaging (PLIIM) based engine for use in a host system, said linear-type PLIIM based engine comprising:

an engine housing having a light transmission aperature;

a support platform mounted within said engine housing;

a linear image formation and detection (IFD) module mounted on said support platform, and having a linear array of image detection elements and also image formation optics having a field of view (FOV) projectable through said light transmission aperature and into an illumination and imaging field, definable external to said engine housing, and in which an object can be presented for illumination and imaging, and said FOV focusing a linear image of said object onto said linear array of image detection elements; and

a pair of planar laser illumination arrays (PLIAs) arranged on opposite sides of said linear image formation and detection module, and mounted on said support platform;

wherein said pair of PLIAs produces a plurality of spatially-incoherent planar laser illumination beam (PLIB) components that are optically combined with respect to other said PLIB components so as to produce a composite planar laser illumination beam (PLIB) that is spatially aligned with respect to said FOV and arranged in coplanar relationship with at least a portion of said FOV;

wherein each said PLIA includes a plurality of planar laser illumination modules (PLIMs),

wherein each said PLIM includes a laser diode and beam focusing and diverging optics for producing one said spatially-incoherent PLIB component;

wherein said composite PLIB produces a number of substantially different individual speckle noise patterns at said linear array of image detection elements during the photo-integration time period thereof;

wherein the level of speckle noise power observed at said linear array of image detection element is reduced through temporal averaging of said substantially different individual speckle noise patterns at said linear array of image detection elements during said photo-integration time period.

16. The linear-type PLIIM based engine of claim 15, wherein a series of linear images of said object are sequentially detected by said linear IFD module as said object relatively moves past said linear IFD module, so that said series of linear images can be grabbed and buffered within said engine housing for subsequent use in constructing two-dimensional images of said object.

17. The linear-type PLIIM based engine of claim 15, wherein each said laser diode is a visible laser diode (VLD).

18. The linear-type PLIIM based engine of claim 15, wherein each said beam focusing and diverging optics comprises a focusing lens and a cylindrical lens.

19. The linear-type PLIIM based engine of claim 15, which further comprises:

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

an image data buffer for buffering said grabbed linear images to form a two-dimensional image.

20. The linear-type PLIIM based engine of claim 15, which further comprises:

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

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

21. The linear-type PLIIM based engine of claim 15, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).

22. The linear-type PLIIM based engine of claim 15, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

23. The linear-type PLIIM based engine of claim 15, wherein said image forming optics have a variable focal distance and a variable focal length providing a varible field of view.

24. The linear-type PLIIM based engine of claim 15, which further comprises a field of view (FOV) folding mirror for folding said FOV onto said linear array of image detection elements.

25. The linear-type PLIIM based engine of claim 15, wherein said FOV folding mirror is mounted on said support platform.

26. The linear-type PLIIM based engine of claim 15, which further comprises a planar laser illumination beam (PLIB) folding mirror for folding said composite PLIB towards said illumination and imaging field.

27. The linear-type PLIIM based engine of claim 15, which further comprises

a field of view (FOV) folding mirror for folding said FOV onto said linear array of image detection elements, and

a planar laser illumination beam (PLIB) folding mirror for folding said composite PLIB towards said illumination and imaging field.

28. The linear-type PLIIM based engine of claim 27, which further comprises a PLIB/FOV sweeping mechanism for sweeping said PLIB and coplanar FOV across a 3-D illumination and imaging field external to said hand-supportable housing.

29. A hand-supportable linear-type planar laser illumination and imaging (PLIIM) based device, comprising:

a hand-supportable housing having a light transmission aperture;

a support platform mounted within said hand-supportable housing;

a linear image formation and detection (IFD) module mounted on said support platform, and having a linear array of image detection elements and also image formation optics having a field of view (FOV) projectable through said light transmission aperture and into an illumination and imaging field, definable external to said hand-supportable housing, and in which an object can be presented for illumination and imaging, and said FOV focusing a linear image of said object onto said linear array of image detection elements; and

a pair of planar laser illumination arrays (PLIAs) arranged on opposite sides of said linear image formation and detection module, and mounted on said support platform;

wherein said pairs of PLIAs produces a plurality of spatially-incoherent planar laser illumination beam (PLIB) components that are optically combined with respect to other said PLIB components so as to produce a composite planar illumination beam (PLIB) that is spatially aligned with respect to said FOV and arranged in a coplanar relationship with at least a portion of said FOV;

wherein each said PLIA includes a plurality of planar laser illumination modules (PLIMs),

wherein each said PLIM includes a laser diode and beam focusing and diverging optics for producing one said spatially-incoherent PLIB component;

wherein said composite PLIB produces a number of substantially different individual speckle noise patterns at said linear array of image detection elements during the photo-integration time period;

wherein the level of speckle noise power observed at said linear array of image detection elements is reduced through temporal averaging of said substantially different individual speckle noise patterns at said linear array of image detection elements during said photo-integration time period.

30. The hand-supportable PLIIM based device of claim 29, wherein a series of linear images of said object are sequentially detected by said linear IFD module as said object relatively moves past said linear IFD module, so that said series of linear images can be grabbed and buffered within said hand-supportable housing for subsequent use in constucting two-dimentional images of said object.

31. The hand-supportable PLIIM based device of claim 29, wherein each said laser diode is a visible laser diode (VLD).

32. The hand-supportable PLIIM based device of claim 29, wherein each said beam focusing and diverging optics comprises a focusing lens and a cylindrical lens.

33. The hand-supportable PLIIM based device of claim 29, which further comprises:

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

an image data buffer for buffering said grabbed linear images to form a two-dimensional image.

34. The hand-supportable PLIIM based device of claim 33, which further comprises:

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 IFD module, and said pair of planar laser illumination arrays.

35. The hand-supportable PLIIM based device of claim 29, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).

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

37. The hand-supportable PLIIM based device of claim 29, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

38. The hand-supportable PLIIM based device of claim 29, which further comprises a field of view (FOV) folding mirror for folding said FOV onto said linear array of image detection elements.

39. The hand-supportable PLIIM based device of claim 29, wherein said FOV folding mirror is mounted on said support platform.

40. The hand-supportable PLIIM based device of claim 29, which further comprises a planar laser illumination beam (PLIB) folding mirror for folding said composite PLIB towards said illumination and imaging field.

41. The hand-supportable PLIIM based device of claim 29, which further comprises

a field of view (FOV) folding mirror for folding said FOV onto said linear array of image detection elements, and

a planar laser illumination beam (PLIB) folding mirror for folding said composite PLIB towards said illumination and imaging field.

42. The hand-supportable PLIIM based device of claim 29, which further comprises a PLIB/FOV sweeping mechanism for sweeping said PLIB and coplanar FOV across a 3-D illumination and imaging field external to said hand-supportable housing.