Digital imaging-based bar code symbol reader employing an LED-based illumination subsystem driven by an automatic light exposure measurement and illumination control subsystem

• US 7,243,847 B2
• Filed: 07/28/2004
• Issued: 07/17/2007
• Est. Priority Date: 11/13/2003
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Knowles, C. Harry, Au, Ka Man, Liu, Yong, Liu, Liang, Schmidt, Mark, Ghosh, Sankar, Kotlarsky, Anatoly, Tao, Xi, Zhang, Wenhua, Amundsen, Thomas, Hou, Rui, Russell, Garrett, Byun, Sung, Yu, Hongpeng, Bonanno, John, Schnee, Michael, Spatafore, Pasqual
• Primary Examiner(s): Kim; Ahshik
• Application Number:
  US10/901,429
• Publication Number:
  US 20050103859A1
• Time in Patent Office: 1,084 Days
• Field of Search: 235/462.22, 235/462.01, 235/462.09, 235/462.24, 235/462.42
• US Class Current: 235/462.22
• CPC Class Codes: G06K 7/10732 Light sources
• 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
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners

Abstract

A digital imaging-based bar code symbol reading device comprises: an automatic object presence detection subsystem; an image formation and detection subsystem employing a CMOS area-type image sensing array; an LED-based illumination subsystem; an automatic light exposure measurement and illumination control subsystem; an image capturing and buffering subsystem; an image-processing bar code symbol reading subsystem; an input/output subsystem; and a system control subsystem for controlling the subsystems. The LED-based illumination subsystem is automatically driven by the automatic light exposure measurement and control subsystem responsive to the generation of control activation signals by the image sensing array and the automatic object presence detection subsystem during object illumination and image capture operations.

Claims

1. A digital imaging-based bar code symbol reading device having a working range, and 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 in which substantially all rows of said area-type image sensing array are enabled, and when substantially all rows of pixels in said area-type image sensing array are in a state of integration operation, automatically generating a first control activation signal;

a light emitting diode (LED) based illumination subsystem for automatically producing LED-based illumination within said FOV from an LED illumination array;

an automatic object presence detection subsystem for automatically producing an object detection field that spatially encompasses a substantiated portion of said FOV within the working range of said digital imaging-based bar code symbol reading device, and detecting the presence of an object within said FOV and generating said second control activation signal in response to such object presence detection;

an automatic light exposure measurement and illumination control subsystem for automatically measuring the light exposure incident upon a central portion of said FOV, and controlling the operation of said LED illumination array, in response to the generation of both said first and second control activation signals, so as to produce LED-based illumination from said LED illumination array and illuminate said detected object therewith during object illumination and image capture operations;

an image capturing and buffering subsystem for capturing and buffering a digital image of the illuminated object, formed and detected by said image formation and detection subsystem;

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

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 controlling and coordinating the operation of said subsystems; and

a housing for containing said subsystems, and having a light transmission panel with an imaging window, through which said FOV extends, said LED-based illumination is projected, and light reflected and scattered off said object is transmitted.

2. The digital imaging-based bar code symbol reading device of claim 1, wherein said LED illumination array includes two sets of flat-top LED light sources without any lenses, mounted on the top and bottom portions of said light transmission panel.

3. The digital imaging-based bar code symbol reading device of claim 2, wherein said LED illumination array further includes two sets of LED light sources provided with spherical lenses, mounted on the top and bottom portions of said light transmission panel.

4. The digital imaging-based bar code symbol reading device of claim 1, wherein said object detection field and said FOV spatially overlap along a substantial portion of said working distance.

5. The digital imaging-based bar code symbol reading device of claim 1, wherein said automatic object presence detection subsystem comprises an IR-based automatic object presence and range detection subsystem, in which the object detection field is an IR-based object detection field having a near-field portion and a far-field portion.

6. The digital imaging-based bar code symbol reading device of claim 5, wherein said automatic object presence detection subsystem is activated at system start-up to continuously monitor said object detection field for an object and provides said system control subsystem with information about the state of an object within both near-field and far-field portions of said object detection field.

7. The digital imaging-based bar code symbol reading device of claim 1, wherein said area-type image sensing array comprises a CMOS area-sensing array.

8. The digital imaging-based bar code symbol reading device of claim 1, wherein said housing has a hand-supportable form factor for using said digital imaging-based bar code symbol reading said device in hand-supported bar code symbol reading applications.

9. The digital imaging-based bar code symbol reading device of claim 1, wherein said housing has a countertop-supportable form factor for using said digital imaging-based bar code symbol reading device in presentation-type bar code symbol reading applications.