Digital image capture and processing engine employing optical waveguide technology for collecting and guiding LED-based illumination during object illumination and image capture modes of operation

• US 7,854,384 B2
• Filed: 12/29/2006
• Issued: 12/21/2010
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Hu, Daniel, Zhu, Xiaoxun, Au, Ka Man, Good, Timothy, Kotlarsky, Anatoly, Hou, Richard, Meagher, Mark
• Primary Examiner(s): Kim; Ahshik
• Application Number:
  US11/648,759
• Publication Number:
  US 20070181689A1
• Time in Patent Office: 1,453 Days
• Field of Search: 235/462.25, 235/462.42, 235/462.15, 235/462.43
• US Class Current: 235/462.25
• CPC Class Codes: G06K 7/10683 Arrangement of fixed elements
• CPC Class Codes: G06K 7/10712 Fixed beam scanning
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03

Abstract

Digital image capture and processing engine of modular design and employing an optical waveguide structure for collecting and guiding LED-based illumination during object illumination and imaging operations. The digital image capture and processing engine also includes apparatus for automatically controlling the duration of illumination produced from LED illumination arrays during object illumination and imaging operations. Such automatic illumination control involves measuring the amount of illumination to which the object be imaged has been exposed, and controlling the duration of illumination produced from the LED illumination arrays based on such measurements during each object illumination and imaging operation. By virtue of the present invention, the digital image capture and processing engine ensures the reliable formation and detection of high quality images in diverse application environments in the digital image capture and processing engine can be used.

Claims

1. A digital image capture and processing engine comprising:

an engine housing;

a digital image formation and detection subsystem, embodied within said engine housing, and having (i) image formation optics for projecting a field of view (FOV) from an area-type image detection array, and upon an object to be imaged during object illumination and imaging operations, and (ii) said area-type image detection array for detecting one or more digital images of the object during object illumination and imaging operations in an image capture mode when detector elements in said image detection array are enabled so as to detect one or more digital images of the object formed on said area-type image detection array;

a LED-based illumination subsystem, embodied within said engine housing, and having an LED illumination array for producing and projecting a field of illumination within said FOV during object illumination and imaging operations;

an automatic illumination control subsystem, embodied within said engine housing, for controlling said LED illumination array during object illumination and imaging operations;

an automatic exposure measurement subsystem, embodied within said engine housing, and including an optical waveguide component arranged for collecting illumination scattered off an illuminated object present in said FOV, and guiding the collected illumination onto a photo-detector, operating independently from said area-type image detection array, for measuring the intensity of said collected illumination and producing an electrical signal representative of said measured intensity; and

an image capturing and buffering subsystem, embodied within said engine housing, for capturing and buffering said one or more digital images detected by the area-type image detection array.

2. The digital image capture and processing engine of claim 1, wherein said digital image formation and detection subsystem comprises a digital camera board on which said area-type image detection array is mounted, along with video memory and digital signal processing circuitry.

3. The digital image capture and processing engine of claim 2, wherein said image formation optics comprises a lens barrel assembly for supporting a plurality of lenses.

4. The digital image capture and processing engine of claim 3, wherein said digital image formation and detection subsystem further comprises a housing for enclosing said area-type image detection array and receiving said lens barrel assembly.

5. The digital image capture and processing engine of claim 2, wherein said LED-based illumination subsystem comprises (i) an illumination board having a central aperture through which said FOV passes during object illumination and imaging operations, and about which a plurality of light emitting diodes (LEDs) are mounted, along with LED driver circuitry, and (ii) an assembly of lenses for focusing and/or shaping illumination emanating from said plurality of LEDs so as to produce said field of illumination within said FOV.

6. The digital image capture and processing engine of claim 5, wherein said digital camera board and said illumination board are arranged in a substantially parallel manner.

7. The digital image capture and processing engine of claim 6, wherein said optical waveguide component extends through a first aperture formed in said illumination board.

8. The digital image capture and processing engine of claim 7, wherein said optical waveguide component is substantially perpendicular to both said illumination board and said digital camera board.

9. The digital image capture and processing engine of claim 3, wherein said automatic illumination control subsystem comprises digital electronic circuitry for controlling said LED driver circuitry.

10. The digital image capture and processing engine of claim 1, wherein said automatic exposure measurement subsystem comprises electronic circuitry, for receiving and processing said electrical signal from said automatic exposure measurement subsystem.

11. The digital image capture and processing engine of claim 2, wherein said image capturing and buffering subsystem comprises video memory, mounted on said digital camera board, for buffering said one or more digital images of the illuminated object detected during object illumination and imaging operations.

12. The digital image capture and processing engine of claim 1, which further comprises a digital image processing subsystem for processing said one or more digital images and producing raw or processed output data, or recognizing or acquiring information graphically represented therein, and producing output data representative of said recognized information.

13. The digital image capture and processing engine of claim 12, which further comprises an input/output subsystem for transmitting said raw or processed output data to an external host system or other information receiving or responding device;

and a system control system for controlling and/or coordinating the operation of said subsystems above.

14. The digital image capture and processing engine of claim 12, wherein said digital image processing subsystem comprises a digital image processing board for processing said one or more digital images.

15. The digital image capture and processing engine of claim 6, wherein a digital image processing board is mounted parallel to said digital camera board and said illumination board, for processing said one or more digital images.

16. The digital image capture and processing engine of claim 1, which further comprises a FOV marking subsystem for projecting, during object illumination and imaging operations, a visible illumination-based FOV marking pattern into said FOV, which visually indicates boundary conditions of said FOV.

17. The digital image capture and processing engine of claim 16, wherein said visible illumination-based FOV marking pattern is selected from the group consisting of a one dot pattern, a two dot pattern, a four dot pattern, a visible line pattern, and a composite four dot and line pattern.

18. The digital image capture and processing engine of claim 13, which further comprises a computing platform for implementing said digital image processing subsystem, said input/output subsystem and said system control subsystem.

19. The digital image capture and processing engine of claim 18, wherein said computing platform comprises (i) memory for storing software libraries, containing code for applications for said digital image capture and processing engine, and (ii) a microprocessor for running said one or more applications.

20. The digital image capture and processing engine of claim 17, wherein said computing platform is implemented on a printed circuit (PC) board.

21. The digital image capture and processing engine of claim 19, wherein said memory comprises a memory architecture that supports a three-tier modular software architecture characterized by an Operating System (OS) layer, a System CORE (SCORE) layer, and an Application layer responsive to the generation of a triggering event within said digital image capture and processing engine.

22. The digital image capture and processing engine of claim 12, wherein said digital image processing subsystem processes said one or more digital images, so as to read one or more code symbols graphically represented in said one or more digital images, and producing output data in the form of symbol character data representative of said read one or more code symbols.

23. The digital image capture and processing engine of claim 22, wherein each said code symbol is a bar code symbol selected from the group consisting of a 1D bar code symbol, a 2D bar code symbol, and a data matrix type code symbol.

24. The digital image capture and processing engine of claim 10, which further comprises an automatic object detection subsystem for automatically detecting the presence of the object in said FOV.

25. The digital image capture and processing engine of claim 10, which further comprises a trigger manually actuatable by an operator of said digital image capturing and processing engine so as to generate a trigger signal.

26. The digital image capture and processing engine of claim 13, which further comprises an automatic object detection subsystem embodied in said engine housing, for automatically detecting the presence of the object in said FOV, and in response thereto, generating a trigger signal indicating a triggering event.

27. The digital image capture and processing engine of claim 1, wherein said engine housing is mounted within a hand-supportable housing.

28. The digital image capture and processing engine of claim 26, wherein said object detection subsystem further comprises an IR-based transmitting and receiving circuits.