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Hand-supportable imaging-based bar code symbol reader employing a CMOS-type image sensor using global exposure techniques

  • US 7,357,325 B2
  • Filed: 07/19/2004
  • Issued: 04/15/2008
  • Est. Priority Date: 11/13/2003
  • Status: Active Grant
First Claim
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1. A hand-supportable digital imaging-based bar code symbol reading device 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 a CMOS area-type image sensing array for detecting imaged light reflected off the object during illumination operations in an image capture mode in which rows of pixels on the image sensing array are enabled;

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

    an automatic light exposure measurement and illumination control subsystem for automatically measuring the light exposure incident upon a portion of said 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;

    an image-processing based bar code symbol reading subsystem for processing 2D images captured and buffered by said image capturing and buffering subsystem and reading 1D and/or 2D bar code symbols represented in said 2D images; and

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

    a system control subsystem for activating and controlling said subsystem components described above in response to a triggering event signal;

    wherein once said CMOS area-type image sensing array is activated by said system control subsystem, and when substantially all rows in said CMOS area-type image sensing array are in a state of integration, said system control subsystem automatically activates said automatic light exposure measurement and illumination control subsystem which, in response thereto, automatically drives the LED-based illumination array in a precise manner so as to globally expose said CMOS area-type image sensing array with narrow-band illumination when substantially all rows of pixels in said CMOS area-type image sensing array are in a state of integration and have a common integration time, thereby enabling said image capturing and buffering subsystem to capture high quality images independent of the relative motion between the object and said hand-supportable digital imaging-based bar code symbol reading device.

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