Hand-supportable digital image-processing based bar code symbol reading system employing image cropping zone (ICZ) framing and post-image capture cropping

• US 7,568,625 B2
• Filed: 12/03/2004
• Issued: 08/04/2009
• 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:
  US11/004,502
• Publication Number:
  US 20080135620A1
• Time in Patent Office: 1,705 Days
• Field of Search: 235/462.24, 235/462.25, 235/462.01, 235/462.09, 235/462.2
• US Class Current: 235/462.24
• CPC Class Codes: G06F 9/44526 Plug-ins; Add-ons
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/10712 Fixed beam scanning
• CPC Class Codes: G06K 7/10732 Light sources
• 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
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence

Abstract

A method of reading bar code symbols comprising the steps of: (a) projecting an image cropping zone (ICZ) framing pattern within the FOV of an image sensing array during wide-area illumination and image capturing operation; (b) visually aligning an object to be imaged within the ICZ framing pattern; (c) forming and capturing an wide-area image of the entire FOV, which spatially encompasses the ICZ framing pattern aligned about the object to be imaged; (d) using automatic software-based image cropping algorithm to automatically crop the pixels within the spatial boundaries defined by the ICZ framing pattern, from those pixels contained in the entire wide-area image frame captured during step (c); and (e) automatically decode processing the image represented by the cropped image pixels in the ICZ framing pattern so as to read a 1D or 2D bar code symbol graphically represented therein.

Claims

1. A method of reading bar code symbols using a hand-supportable image-processing based bar code symbol reading system having an image sensing array with a field of view (FOV), an LED-based illumination subsystem with an LED illumination array, a wide-area illumination and image capturing mode of operation, and an automatic software-based image cropping algorithm, said method comprising the steps of:

(a) projecting an image cropping zone (ICZ) framing pattern within the FOV of said image sensing array during said wide-area illumination and image capturing mode of operation;

(b) a user visually aligning an object to be imaged within said ICZ framing pattern;

(c) simultaneously projecting an illumination pattern from said LED illumination array onto the object in said FOV while projecting said ICZ framing pattern within said FOV, and forming and detecting a wide-area digital image of the entire FOV of said image sensing array, which spatially encompasses said ICZ framing pattern aligned about at least a portion of the object to be imaged;

(d) using said automatic software-based image cropping algorithm to automatically locate said ICZ framing pattern in said wide-area digital image of the entire said FOV, by tracing corner points or border lines that identify boundaries of said ICZ framing pattern, and cropping the image pixels within the spatial boundaries of said ICZ framing pattern, prior to performing decode-processing operations, to provide a cropped digital image; and

(e) automatically decode processing the cropped digital image represented by the cropped image pixels in said ICZ framing pattern so as to read a 1 D or 2 D bar code symbol graphically represented in said cropped digital image.

2. The method of claim 1, which further comprises:

(f) outputting to a host system, the symbol character data representative of the decoded 1 D or 2 D bar code symbol.

3. The method of claim 1, wherein step (a) comprising generating a laser beam which is transmitted through a light diffractive element to produce a plurality of laser beamlets that define the spatial boundaries of said ICZ framing pattern for the user to see during bar code illumination and imaging operations.

4. A hand-supportable image-processing based bar code symbol reading system having a wide-area illumination and image capturing mode of operation, said hand-supportable image-processing based bar code symbol reading system comprising:

a hand-supportable housing;

an image sensing array with a field of view (FOV), disposed within said hand-supportable housing;

an LED-based illumination subsystem with an LED illumination array, disposed within said hand-supportable housing;

an image processor, disposed within said hand-supportable housing, programmed to carry out an automatic software-based image cropping algorithm;

an optics-based mechanism, disposed within said hand-supportable housing, for simultaneously projecting an image cropping zone (ICZ) framing pattern within said FOV, while said LED illumination array projects illumination onto an object in said FOV, during said wide-area illumination and image capturing mode of operation; and

an image-processing based bar code symbol reading module disposed within said hand-supportable housing;

whereby, when a user visually aligns the object to be imaged within said ICZ framing pattern, said LED illumination array projects illumination onto said object in said FOV while said optics-based mechanism projects said ICZ framing pattern onto at least a portion of the object in said FOV, and said image sensing array detects a wide-area digital image of the entire FOV so that the detected wide-area digital image spatially encompasses said ICZ framing pattern aligned about the object to be imaged;

then said automatic software-based image cropping algorithm is used to automatically locate said ICZ framing pattern in said wide-area digital image of the entire said FOV, by tracing corner points or border lines that identify boundaries of said ICZ framing pattern, and cropping the image pixels within the spatial boundaries of said ICZ framing pattern, prior to performing decode-processing operations, to provide a cropped digital image;

then the cropped digital image represented by the cropped image pixels in said ICZ framing pattern is automatically decode-processed by said image-processing based bar code symbol reading module so as to read a 1 D or 2 D bar code symbol graphically represented in the cropped digital image; and

then the symbol character data representative of the decoded 1 D or 2 D bar code symbol is outputted to a host system.

5. The hand-supportable image-processing based bar code symbol reading system of claim 4, wherein said an optics-based mechanism comprises a laser source for generating a visible laser beam which is transmitted through a light diffractive element so as to produce a plurality of laser beamlets that define the spatial boundaries of said ICZ framing pattern for the user to see during object illumination and imaging operations.