Patent ID: 7213762
Filing Date: 2007-05-08
Classification: G06K

Abstract:
1. A digital imaging-based bar code symbol reading system comprising: a hand-supportable housing; an area image formation and detection subsystem, disposed in said hand-supportable housing, and having image formation optics for producing a field of view (FOV) upon an object to be imaged and a CMOS area image sensing array with a plurality of rows of pixels for photo-detecting an image of the object formed by narrow-band illumination reflected off the object during illumination operations; a LED-based illumination subsystem, disposed in said hand-supportable housing, for producing a field of narrow-band illumination within said FOV during the image capture mode, so that substantially only narrow-band illumination is transmitted from said LED-based illumination subsystem, scattered from the illuminated object, and transmitted through a transmission-type optical filter subsystem integrated within said hand-supportable housing for detection by said CMOS area image sensing array while all other components of ambient light outside said narrow-band of wavelength are substantially rejected; an automatic light exposure measurement and illumination control subsystem, disposed in said hand-supportable housing, for automatically measuring the light exposure incident upon a central portion of said FOV and controlling the duration of narrow-band illumination produced from said LED-based illumination subsystem during said image capture mode; an image capturing and buffering subsystem, disposed in said hand-supportable housing, for capturing and buffering 2D digital images detected by the image formation and detection subsystem; and an image-processing based bar code symbol reading subsystem, disposed in said hand-supportable housing, for processing 2D digital images captured and buffered by said image capturing and buffering subsystem and reading 1D and 2D bar code symbols represented in said 2D digital images; an input/output subsystem, disposed in said hand-supportable housing, for outputting processed image data to an external host system or other information receiving or responding device; and a system control subsystem, disposed in said hand-supportable housing, for controlling each said subsystem; wherein, during said image capture mode, and only when substantially all rows of pixels on said CMOS area image sensing array are enabled and simultaneously ready for photo-integration, said LED-based illumination subsystem is activated so as to produce narrow-band illumination into said FOV while said automatic light exposure measurement and illumination control subsystem automatically measures the light exposure incident upon a central portion of said FOV, and controls the time duration that narrow-band illumination is produced from said LED-based illumination subsystem, transmitted through said narrow-band transmission-type optical filter subsystem and onto the object, and scattered off the illuminated object and transmitted back through said narrow-band transmission-type optical filter subsystem and onto said CMOS area-type image sensing array so as to produce a quality 2D digital image of the illuminated object during said image capture mode.