Method of performing auto-discrimination of 1D/2D bar code symbologies in a semi-automatic hand-supportable imaging-based bar code symbol reader having narrow-area and wide-area image capture modes of operation

• US 7,225,989 B2
• Filed: 07/22/2004
• Issued: 06/05/2007
• 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, 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:
  US10/897,389
• Publication Number:
  US 20050103847A1
• Time in Patent Office: 1,048 Days
• Field of Search: 235/462.01, 235/462.09, 235/462.11, 235/462.32, 235/462.42, 235/472.01
• US Class Current: 235/472.01
• 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

Method of performing autodiscrimination of 1D/2D bar code symbologies in a semi-automatic hand-supportable imaging-based bar code symbol reader having narrow-area and wide-area image capture modes of operation. The hand-supportable digital imaging-based bar code symbol reading device comprises: an automatic object presence and range detection subsystem; a multi-mode image formation and detection subsystem having narrow-area and wide area image capture modes of operation; a multi-mode LED-based illumination subsystem having narrow-area and wide area illumination modes of operation; an automatic light exposure measurement and illumination control subsystem; an image capturing and buffering subsystem; a multi-mode image-processing bar code symbol reading subsystem; an input/output subsystem; a manually-activatable trigger switch; and a system control subsystem integrated with each of the above-described subsystems.

Claims

1. A method of performing auto-discrimination of 1D/2D bar code symbologies in a hand-supportable semi-automatic imaging-based bar code symbol reader having narrow-area and wide-area image capture modes of operation, said method comprising the steps of:

(a) providing a hand-supportable semi-automatic digital imaging-based bar code symbol reading device including

a hand-supportable housing;

a multi-mode 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 image sensing array for detecting imaged light reflected off the object during illumination operations in either (i) a narrow-area image-capture mode in which a few central rows of pixels on the image sensing array are enabled, or (ii) a wide-area image-capture mode in which substantially all rows of the image sensing array are enabled;

a multi-mode LED-based illumination subsystem for producing fields of narrow-area and wide-area narrow-band illumination within said FOV during narrow-area and wide-area image capture modes, respectively;

an automatic object presence detection subsystem for producing an object detection field within said FOV, and detecting an object present therein;

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-based multi-mode illumination subsystem;

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

a multi-mode image-processing based bar code symbol reading subsystem for processing 2D digital images captured and buffered by said image capturing and buffering subsystem and reading 1D and 2D bar code symbols represented therein;

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

a manually-actuatable trigger switch integrated with said hand-supportable housing, for generating a first control activation signal; and

a system control subsystem for controlling the operation of each said subsystem;

(b) presenting an object bearing a bar code structure within said object detection field;

(c) automatically detecting said object present within said object detection field of said automatic object presence and range detection subsystem, and in response thereto, automatically generating and providing a first control activation signal to said system control subsystem;

(d) controlling under said system control subsystem the following events;

(1) operating said multi-mode image formation and detection subsystem in said narrow-area image capture mode in which a few central rows of pixels on the image sensing array are enabled,

(2) operating said multi-mode LED-based illumination subsystem to produce a narrow area field of narrow-area narrow-band illumination within said FOV during the narrow-area image capture mode,

(3) operating said automatic light exposure measurement and illumination control subsystem to automatically measure the light exposure incident upon a central portion of said FOV, and automatically control the operation of said LED-based multi-mode illumination subsystem,

(4) operating said image capturing and buffering subsystem to capture and buffer a 2D narrow-area digital image detected by said image formation and detection subsystem, and

(5) operating said multi-mode image-processing based bar code symbol reading subsystem to process said 2D narrow-area digital image captured and buffered by said image capturing and buffering subsystem; and

(e) if said multi-mode image-processing based bar code symbol reading subsystem can read a 1D bar code symbol structure within a first predetermined time period, then said input/output subsystem outputs processed image data to an external host system or other information receiving or responding device.

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

(f) if said multi-mode image-processing based bar code symbol reading subsystem cannot read a 1D bar code symbol structure within a first predetermined time period and the user manually actuates said manually-actuatable trigger switch within said first predetermined time period, then controlling under said system control subsystem the following events;

(1) operating said multi-mode area image formation and detection subsystem in said wide-area image capture mode in which substantially all rows of pixels on the image sensing array are enabled,

(2) operating said multi-mode LED-based illumination subsystem to produce a field of wide-area narrow-band illumination within said FOV during said wide area image-capture mode,

(3) operating said automatic light exposure measurement and illumination control subsystem to automatically measure the light exposure incident upon a central portion of said FOV, and control the operation of said LED-based multi-mode illumination subsystem in response to input provided by said automatic object presence detection subsystem,

(4) operating said image capturing and buffering subsystem to capture and buffer a 2D wide-area digital image detected by said image formation and detection subsystem, and

(5) operating said multi-mode image-processing based bar code symbol reading subsystem to process said 2D wide-area digital image captured and buffered by said image capturing and buffering subsystem.

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

(g) if said multi-mode image-processing based bar code symbol reading subsystem can read a 1D or a 2D bar code symbol structure within a second predetermined time period, then said input/output subsystem outputs processed image data to an external host system or other information receiving or responding device.

4. The method of claim 3, which further comprises:

(h) if said multi-mode image-processing based bar code symbol reading subsystem cannot read a 1D or a 2D bar code symbol structure within said second predetermined time period, and the user continues to manually actuate said manually-actuatable trigger switch, then said system control subsystem continues to control said multi-mode image formation and detection subsystem, said multi-mode LED-based illumination subsystem, said automatic light exposure measurement and illumination control subsystem, said image capturing and buffering subsystem and said multi-mode image-processing based bar code symbol reading subsystem so as to enable said device to read either a 1D and/or a 2D bar code symbol structure within said captured wide-area digital image.

5. The method of claim 4, wherein said device has at least two primary modes in which said multi-mode image-processing based bar code symbol reading subsystem can operate, namely:

a first mode of operation, wherein said multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process said captured 2D narrow-area digital image, without feature extraction and marking operations so as read one or more 1D bar code symbols represented therein; and

a second mode of operation, wherein said multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process said captured 2D wide-area digital image, starting from the center or sweep spot of said wide-area digital image of the object at which the user would have aimed the bar code reader, so as to search for one or more bar code symbols represented therein, by searching in a helical manner through frames or blocks of extracted image feature data and marking said extracted image feature data, and processing the corresponding raw digital image data until a 1D or 2D bar code symbol is recognized/read within said captured wide-area digital image.

6. The method of claim 5, wherein said device has at three additional primary modes, in which said multi-mode image-processing bar code symbol reading subsystem can operate, namely:

a third mode of operation, wherein said multi-mode bar code symbol reading subsystem is configured to automatically process a specified region of interest (ROI) in said captured 2D wide-area digital image so as to search for one or more bar codes represented therein, in response to coordinate data specifying the location of the bar code within said FOV;

a fourth mode of operation, wherein said multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process said captured 2D wide-area digital image so as to search for one or more bar codes represented therein in an incremental manner, and to continue searching until the entire digital image is processed; and

a fifth mode of operation, wherein said multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process said captured 2D wide-area digital image along any one or more predetermined virtual scan line orientations, without feature extraction and marking operations used in said second and fourth modes, so as to read one or more bar code symbols represented therein.