Method of and apparatus for dynamically and adaptively controlling system control parameters in a multi-mode image capture and processing system

• US 20070040035A1
• Filed: 04/20/2006
• Published: 02/22/2007
• 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: Zhu, Xiaoxun, Veksland, Michael, Good, Timothy, Kotlarsky, Anatoly, Hou, Richard, Meagher, Mark, Hu, Daniel, Au, Ka
• Granted Patent: US 7,464,877 B2
• Time in Patent Office: Days
• US Class Current: 235/462.450
• 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

Disclosed is a method of and apparatus for dynamically and adaptively controlling system control parameters (SCPs) in a multi-mode image capture and processing system, wherein (i) automated real-time exposure quality analysis of captured digital images is automatically performed in a user-transparent manner, and (ii) system control parameters (e.g. illumination and exposure control parameters) are automated reconfigured based on the results of such exposure quality analysis, so as to achieve improved system functionality and/or performance in diverse environments.

Claims

1-29. -29. (canceled)

30. A hand-supportable digital imaging-based bar code symbol reading system comprising:

a hand-supportable housing;

an image formation and detection subsystem including (i) image formation optics for producing a field of view (FOV) upon an object to be imaged, and (ii) an area-type image sensing array for detecting imaged light reflected off the object during illumination operations in an image capture mode, and producing a 2D image of the illuminated object;

a LED-based illumination subsystem having an LED illumination array for producing a field of illumination within the FOV of said image formation and detection subsystem during said image capture mode;

an image cropping pattern generator for generating a visible illumination-based image cropping pattern (ICP) projected within the field of view (FOV) of said image formation and detection subsystem;

an object presence and range detection subsystem for producing an object detection field within the FOV of said image formation and detection subsystem;

an automatic light exposure measurement and illumination control subsystem for measuring illumination levels in a central portion of the FOV and controlling the operation of said LED-based illumination subsystem;

an image capturing and buffering subsystem for capturing and buffering 2D images detected by said image formation and detection subsystem;

a cropped image locating module for processing captured and buffered images so as to locate the image region corresponding to the image region defined by said image cropping pattern (ICP), and cropping said image region;

a perspective correction and scaling module for processing said cropped image region and correcting the perspective of said cropped image region and scaling the perspective corrected image to a predetermined pixel image size suitable for decode-processing;

an image-processing based bar code symbol reading subsystem for decode-processing cropped and scaled images generated by said image perspective correction and scaling module, and reading 1D and 2D bar code symbols represented in said captured 2D images; and

an input/output subsystem for outputting processed image data and the like to an external host system or other information receiving or responding device.

31. The hand-supportable digital imaging-based bar code symbol reading system of claim 30, wherein said image cropping pattern generator comprising a VLD and a pair of flat-convex lenses arranged before the VLD, for generating and projecting a two dot image cropping pattern (ICP) within the field of view of the of the multi-mode area-type image formation and detection subsystem.

32. The hand-supportable digital imaging-based bar code symbol reading system of claim 31, wherein said VLD-based image cropping pattern generator comprises said pair of flat-convex lenses focus naturally diverging light rays from said VLD into two substantially parallel beams of laser illumination, thereby producing a two (2) dot image cropping pattern (ICP) within the field of view of said image formation and detection subsystem.

33. The hand-supportable digital imaging-based bar code symbol reading system of claim 30, wherein said VLD-based image cropping pattern generator comprises a VLD and a biconical lens arranged before said VLD, and four flat-convex lenses arranged in four corners, for generating and projecting a four (4) dot image cropping pattern (ICP) within the field of view of said image formation and detection subsystem;

34. The hand-supportable digital imaging-based bar code symbol reading system of claim 310, wherein said image cropping pattern generator comprises a VLD and a light diffractive optical (DOE) element forming an optical assembly for generating and projecting a four (4) dot image cropping pattern (ICP) within the field of view of said image formation and detection subsystem.

35. A digital image capture and processing engine comprising:

an image formation and detection subsystem having image formation optics for producing a field of view (FOV) upon an object to be imaged, and an area-type image sensing array for detecting imaged light reflected off the object during illumination operations in an image capture mode, and producing a 2D image of the illuminated object;

a LED-based illumination subsystem having an LED illumination array for producing a field of illumination within the FOV of said image formation and detection subsystem during said image capture mode;

an optical waveguide component for measuring light intensity within a central portion of FOV of the engine for purposes of automatic illumination control of the LED illumination arrays illuminating the field of the view (FOV) of said digital image capture and processing engine; and

an image cropping pattern generator for generating a visible illumination-based image cropping pattern (ICP) projected within the field of view (FOV) of said area-type image formation and detection subsystem;

an image capturing and buffering subsystem for capturing and buffering 2-D images detected by said image formation and detection subsystem;

a cropped image locating module for processing captured and buffered images so as to locate the image region corresponding to the image region defined by said image cropping pattern (ICP), and cropping said image region; and

an image-processing based bar code symbol reading subsystem for decode-processing cropped images generated by said image perspective correction and scaling module, and reading 1D and 2D bar code symbols represented in said captured 2D images; and

an input/output subsystem for outputting processed image data and the like to an external host system or other information receiving or responding device.

36. The digital image capture and processing engine of claim 35, which further comprises:

a perspective correction and scaling module for processing said cropped image region and correcting the perspective of said cropped image region and scaling the perspective corrected image to a predetermined pixel image size suitable for decode-processing.

37. The digital image capture and processing engine of claim 36, which further comprises:

an automatic light exposure measurement and illumination control subsystem for measuring illumination levels in a central portion of the FOV and controlling the operation of said LED-based illumination subsystem.

38. The digital image capture and processing engine of claim 37, which further comprises:

an object presence and range detection subsystem for producing an object detection field within the FOV of said image formation and detection subsystem.

39. A method of dynamically and adaptively controlling system control parameters (SCPs) in a digital image capture and processing system having system control parameters including illumination and exposure control parameters, said comprising the steps of:

(a) capturing digital images of an object using said digital image capture and processing system;

(b) automating analyzing, in real-time, the exposure quality of captured digital images in a user-transparent manner; and

(c) automated reconfiguring one or more of said system control parameters (SCPs) in said digital image capture and processing system, based on the results of such exposure quality analysis, so as to achieve improved system functionality and/or performance in diverse environments.

40. A digital image-processing based bar code symbol reader system having system control parameters including illumination and exposure control parameters, said comprising:

an image formation and detection subsystem having image formation optics for producing a field of view (FOV) upon an object to be imaged, and an area-type image sensing array for detecting imaged light reflected off the object during illumination operations in an image capture mode, and producing a 2D image of the illuminated object;

a LED-based illumination subsystem having an LED illumination array for producing a field of illumination within the FOV of said image formation and detection subsystem during said image capture mode;

an image-processing based bar code symbol reading subsystem for decode-processing 2D images detected by said image formation and detection subsystem, and reading 1D and 2D bar code symbols represented in said 2D images; and

an adaptive control system for controlling operations within said image-processing based bar code symbol reader system, including object illumination, image capturing and image processing operations;

wherein said adaptive system performs the following functions in an automated manner;

(a) analyzes in real-time, the exposure quality of captured digital images in a user-transparent manner; and

(b) reconfigures one or more of said system control parameters in said digital image-processing based bar code symbol reader system, based on the results of such exposure quality analysis, so as to achieve improved system functionality and/or performance in diverse environments.

41. The digital imaging-based bar code symbol reading system of claim 40, wherein said system control parameters (SCPs) are selected from the group consisting of:

the shutter mode of the image sensing array employed in the system;

the electronic gain of said area-type image sensing array;

the programmable exposure time for each block of imaging pixels within said area-type image sensing array;

the illumination mode of the system;

automatic illumination control (i.e. ON or OFF);

illumination field type;

image capture mode;

image capture control; and

automatic object detection mode of operation.