PLANAR LASER ILLUMINATION AND IMAGING (PLIIM) DEVICE EMPLOYING A LINEAR IMAGE DETECTION ARRAY HAVING VERTICALLY-ELONGATED IMAGE DETECTION ELEMENTS, WHEREIN THE HEIGHT OF THE VERTICALLY-ELONGATED IMAGE DETECTION ELEMENTS AND THE F/# PARAMETER OF THE IMAGE FORMATION OPTICS ARE CONFIGURED TO REDUCE SPECKLE-PATTERN NOISE POWER THROUGH SPATIAL-AVERAGING OF DETECTED SPECKLE-NOISE PATTERNS

• US 6,997,386 B2
• Filed: 03/21/2002
• Issued: 02/14/2006
• 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: Good, Timothy A., Knowles, C. Harry, Tsikos, Constantine J., Giordano, Patrick A.
• Primary Examiner(s): Le, Thien M.
• Application Number:
  US10/105,961
• Publication Number:
  US 20030035460A1
• Time in Patent Office: 1,426 Days
• Field of Search: 23546201-46246, 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 planar laser illumination and imaging (PLIIM) based device a linear image formation and detection (IFD) module characterized by an F/# parameter mounted on a support platform. The IFD module has a linear image detection array with vertically elongated image detection elements and image formation optics having a field of view (FOV) projected through the light transmission window into an illumination and imaging field external to the hand-supportable housing and in which an object is presented for illumination and imaging. Each vertically-elongated image detection element having a height dimension (H) that is substantially greater than the width dimension (W) thereof. A pair of planar laser illumination arrays (PLIAs) is mounted within the hand-supportable housing and arranged on opposite sides of linear image formation and detection module. Each PLIA includes a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) components which are spatially aligned to produce a composite planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of the FOV. Each PLIM includes a laser diode and beam focusing and diverging optics for producing one PLIB component. For a given wavelength of planar laser illumination, the height dimension (H) of each image detection element is selected to provide the largest possible spatial averaging area, while the F/# parameter of the linear IFD module is selected to provide the smallest possible average speckle noise pattern size along the height dimension of vertically-elongated image detection elements so that more individual speckle noise patterns can occur along the height dimension of each vertically-elongated image detection element in the linear IFD module. A series of linear images of object are sequentially detected by the linear IFD module as the object moves past the hand-supportable housing, so that the series of linear images can be grabbed and buffered for subsequent use in constructing two-dimensional images of the object. The level of speckle noise power observed at the linear image detection array is reduced through the spatial averaging of individual speckle noise patterns occurring along the height dimension of the image detection elements.

Claims

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

a hand-supportable housing having a light transmission window;

a linear image formation and detection (IFD) module characterized by an F/# parameter, mounted within said hand-supportable housing, and having a linear image detection array with vertically elongated image detection elements and image formation optics having a field of view (FOV) projected through said tight transmission window into an illumination and imaging field external to said hand-supportable housing and in which an object is presented for illumination and imaging, each said vertically-elongated image detection element having a height dimension (H) that is greater than the width dimension (W) thereof; and

a laser illumination mechanism, mounted within said hand-supportable housing, for producing a laser illumination beam of substantially planar geometry, arranged in a coplanar relationship with a portion of said FOV;

wherein, for a given wavelength or laser illumination, the height dimension (H) of each said image detection element is selected to provide the largest possible spatial averaging area, while the F/# parameter of said linear IFD module is selected to provide the smallest possible average speckle noise pattern size along the height dimension of said vertically-elongated image detection elements so that more individual speckle noise patterns can occur along the height dimension of each said vertically-elongated image detection element in said linear IFD module;

whereby a series of linear images of said object are sequentially detected by said linear IFD module as said object moves past said hand-supportable housing, 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 the level of speckle noise power observed at said linear image detection array is reduced through the spatial averaging of said individual speckle noise patterns occurring along the height dimension of said image detection elements.

2. The hand-supportable linear-type PLIIM based device of claim 1, wherein said F/# parameter of said linear IFD module is reduced by increasing the aperture of said IFD module or by increasing the height dimension (H) of each said vertically-elongated image detection element.

3. The hand-supportable linear-type PLIIM based device of claim 1, wherein the height dimension (H) of each said image detection element is chosen to have the largest possible spatial averaging area, and the F/# of said linear IFD module is chosen to have the lowest possible value without increasing the aberrations in said linear IFD module to blur the optical signal received thereby.

4. The hand-supportable linear-type PLIIM based device of claim 1, wherein the height dimension (H) of each said vertically-elongated image detection element is on the order of about 56 microns.

5. The hand-supportable linear-type PLIIM based device of claim 1, wherein said laser illumination mechanism comprises:

a pair of planar laser illumination arrays (PLIAs) mounted within said hand-supportable housing and arranged on opposite sides of said linear image formation and detection module, each said PLIA including a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) components which are spatially aligned to produce a composite planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of said FOV.

6. The hand-supportable linear-type PLIIM based device of claim 5, wherein each said PLIM includes a laser diode and beam focusing and diverging optics for producing one said PLIB component.

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

a LCD display panel integrated with said hand-supportable housing, for displaying images captured by said linear image detection array and information provided by a host computer system or other information supplying device; and

a manual data entry keypad integrated with said hand-supportable housing, for manually entering data into said hand-supportable linear-type PLIIM based device during diverse types of information-related transactions supported thereby.

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

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

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

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.

9. The hand-supportable linear-type 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).

10. The hand-supportable linear-type 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.

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

12. The hand-supportable linear-type 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.

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

a hand-supportable housing having a light transmission window;

a linear image formation and detection (IFD) module characterized by an F/# parameter, mounted within said hand-supportable housing, and having a linear image detection array with vertically elongated image detection elements and image formation optics having a field of view (FOV) projected through said light transmission window into an illumination and imaging field external to said hand-supportable housing and in which an object is presented for illumination and imaging, each said vertically-elongated image detection element having a height dimension (H) that is substantially greater than the width dimension (W) thereof, and

pair of planar laser illumination arrays (PLIAs) mounted within said hand-supportable housing and arranged on opposite sides of said linear image formation and detection module, each said PLIA including a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) components which are spatially aligned to produce a composite planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of said FOV, and each said PLIM including a laser diode and beam focusing and diverging optics for producing one said PLIB component;

wherein, for a given wavelength of planar laser illumination, the height dimension (H) of each said image detection element is selected to provide the largest possible spatial averaging area, while the F/# parameter of said linear IFD module is selected to provide the smallest possible average speckle noise pattern size along the height dimension of said vertically-elongated image detection elements so that mare individual speckle noise patterns can occur along the height dimension of each said vertically-elongated image detection element in said linear IFD module;

whereby a series of linear images of said object are sequentially detected by said linear IFD module as said object moves past said hand-supportable housing, 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 the level of speckle noise power observed at said linear image detection array is reduced through the spatial averaging of said individual speckle noise patterns occurring along the height dimension of said image detection elements.

14. The hand-supportable linear-type PLIIM based device claim 13, wherein said F/# parameter of said linear IFD module is reduced by increasing the aperture of said IFD module or by increasing the height dimension (H) of each said vertically-elongated image detection element.

15. The hand-supportable linear-type PLIIM based device of claim 13, wherein the height dimension (H) of each said image detection element is chosen to have the largest possible spatial averaging area, and the F/# of said linear IFD module is chosen to have the lowest possible value without increasing the aberrations in said linear IFD module to blur the optical signal received thereby.

16. The hand-supportable linear-type PLIIM based device of claim 13, wherein the height dimension (H) of each said vertically-elongated image detection element is on time order of about 56 microns.

17. The hand-supportable linear-type PLIIM based device of claim 13, which further comprises:

a LCD display panel integrated with said hand-supportable housing, for displaying images captured by said linear image detection array and information provided by a host computer system or other information supplying device; and

a manual data entry keypad integrated with said hand-supportable housing, for manually entering data into said hand-supportable linear-type PLIIM based device during diverse types of information-related transactions supported thereby.

18. The hand-supportable linear-type PLIIM based device of claim 13, which further comprises:

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

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

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.

19. The hand-supportable linear-type PLIIM based device of claim 13, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).

20. The hand-supportable linear-type PLIIM based device of claim 13, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed held of view.

21. The hand-supportable linear-type PLIIM based device of claim 13, wherein said image forming optics have a variable focal distance and a fixed focal length providing a fixed field of view.

22. The hand-supportable linear-type PLIIM based device of claim 13, wherein said image forming optics have a variable focal distance and a variable focal length providing a variable field of view.

23. A linear-type planar laser illumination and imaging (PLIIM) based engine for installation and use in a hand-supportable housing, comprising;

a linear image formation and detection (IFD) module characterized by an F/# parameter, mounted on a support platform, and having a linear image detection array with vertically elongated image detection elements and image formation optics having a field of view (FOV) projectable into an illumination and imaging field in which an object is presented for illumination and imaging, each said vertically-elongated image detection element having a height dimension (H) that is substantially greater than the width dimension (W) thereof; and

a laser illumination mechanism mounted on said support platform, for producing a laser illumination beam (PLIB) of substantially planar geometry, arranged in a coplanar relationship with a portion of said FOV;

wherein, for a given wavelength of laser illumination, the height dimension (H) of each said image detection element is selected to provide the largest possible spatial averaging area, while the F/# parameter of said linear IFD module is selected to provide the smallest possible average speckle noise pattern size along the height dimension of said vertically-elongated image detection elements so that more individual speckle noise patterns can occur along the height dimension of each said vertically-elongated image detection element in said linear IFD module;

whereby a series of linear images of said object can be sequentially detected by said linear IFD module as said object moves past said linear IFD module, 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 the level of speckle noise power observed at said linear image detection array is reduced through the spatial averaging of said individual speckle noise patterns occurring along the height dimension of said image detection elements.

24. The linear-type PUIIM based engine of claim 23, wherein each said PLIM includes a laser diode and beam focusing and diverging optics for producing one said PLIB component.

25. The linear-type PLIIM base engine of claim 23, wherein said F/# parameter of said linear IFD module is reduced by increasing the aperture of said IFD module or by increasing the height dimension (H) of each said vertically-elongated image detection element.

26. The linear-type PLIIM based engine of claim 23, wherein the height dimension (H) of each said image detection element is chosen to have the largest possible spatial averaging area, and the F/#of said linear IFD module is chosen to have the lowest possible value without increasing the aberrations in said linear IFD module to blur the optical signal received thereby.

27. The linear-type PLIIM based engine of claim 23, wherein the height dimension (H) of each said vertically-elongated image detection element is on the order of about 56 microns.

28. The linear-type PLIIM based engine of claim 23, wherein said laser illumination mechanism comprises:

a pair of planar laser illumination arrays (PLIAs) mounted within said hand-supportable housing and arranged an opposite sides of said linear image formation and detection module, each said PLIA including a plurality of planar laser illumination modules (PLIMs) for producing a plurality of spatially-incoherent planar laser illumination beam (PLIB) components which are spatially aligned to produce a composite planar laser illumination beam (PLIB) arranged in a coplanar relationship with a portion of said FOV.

29. The linear-type PLIIM based engine of claim 23, which further comprises;

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

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

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.

30. The linear-type PLIIM based engine of claim 23, wherein said image forming optics have a fixed focal distance and a fixed focal length providing a fixed field of view (FOV).

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

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

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