Hand-supportable semi-automatic imaging-based bar code reading system wherein an led-based illumination subsystem automatically illuminates a detected target object in a narrow-area field of illumination, and illuminates the detected target object in a wide-area field of illumination upon manual activation of a trigger switch

• US 7,188,770 B2
• Filed: 07/16/2004
• Issued: 03/13/2007
• 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:
  US10/893,797
• Publication Number:
  US 20050103855A1
• Time in Patent Office: 970 Days
• Field of Search: 235/462.22, 235/462.23, 235/462.24, 235/462.25, 235/462.09
• 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 hand-supportable Digital Imaging-Based Bar Code Symbol Reading Device comprises: an IR-based Object Presence and Range Detection Subsystem; A Multi-Mode Area-type 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; an manuallyactivatable trigger switch; a System Mode Configuration Parameter Table; and a System Control Subsystem integrated with each of the above-described subsystems. The bar code reading device can be configured and operated in numerous programmable modes of system operation to automatically read 1D and 2D bar code symbologies in a high-speed manner using advanced modes of image processing on captured images.

Claims

1. A hand-supportable digital imaging-based bar code symbol reading device supporting narrow-area and wide-area modes of illumination and image capture, said hand-supportable digital imaging-based bar code symbol reading device comprising:

a hand-supportable housing;

a multi-mode area image formation and detection subsystem having image formation optics for producing a field of view (FOV) upon a target object to be imaged and an area image sensing array for detecting imaged light reflected off the target 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 narrow and wide area fields of narrow-band illumination within the FOV of said image formation and detection subsystem during narrow and wide area image capture modes, respectively;

an automatic object presence detection subsystem for producing an object detection field spatially encompassed within the FOV of said multi-mode area image formation and detection subsystem, and automatically detecting the presence of said target object within said FOV;

an image capturing and buffering subsystem for capturing and buffering 2D images detected by said area image sensing array in said multi-mode area image formation and detection subsystem;

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

an input/output subsystem for outputting processed image data from said multi-mode image processing based bar code symbol reading subsystem; and

a system control subsystem for controlling the subsystem components described above; and

a manually-actuated trigger switch integrated with said hand-supportable housing, for generating a first control activation signal for use by said system control subsystem when activating particular subsystems to certain states of subsystem operation;

wherein,

(i) when said automatic object presence detection subsystem automatically detects the presence of said target object within said FOV, said multi-mode LED-based illumination subsystem automatically illuminates the target object in a narrow-area field of narrow-band illumination while said multi-mode area image formation and detection subsystem captures a narrow-area image of an aligned 1D bar code symbol on the target object, and

(ii) when said device is manually switched into a wide-area illumination and image capture mode upon manual actuation of said manually-actuated trigger switch, said multi-mode LED-based illumination subsystem illuminates the target object in a wide-area field of narrow-band illumination, while the multi-mode image formation and detection subsystem captures a wide-area image of randomly-oriented 1D or 2D code symbols on the target object.

2. The hand-supportable digital imaging-based bar code symbol reading device of claim 1, which further comprises an automatic light exposure measurement and illumination control subsystem, for measuring the light exposure incident upon a central portion of said FOV, and automatically controlling the operation of said multi-mode LED-based illumination subsystem in response to said measured incident light exposure so as to control the intensity and duration of said narrow and wide area fields of narrow-based illumination within said FOV.

3. The hand-supportable digital imaging-based bar code symbol reading device of claim 1, wherein said multi-mode image-processing based bar code symbol reading subsystem comprises a first mode of operation, and wherein said hand-supportable digital imaging-based bar code symbol reading device further comprises a manually-triggered single-attempt 1D single-read mode employing said first mode of said multi-mode image-processing bar code symbol reading subsystem.

4. The hand-supportable digital imaging-based bar code symbol reading device of claim 3 wherein during said first mode, said multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process a captured narrow-area frame of digital image data, without feature extraction and marking operations, so as to read a one or more bar code symbols represented in said frame of digital image data.

8. The hand-supportable digital imaging-based bar code symbol reading device of claim 3, wherein said manually-triggered single-attempt 1D single-read mode involves configuration of the system as follows:

disabling said automatic object presence and range detection subsystem; and

enabling the use of said manually-actuated trigger switch, the narrow-area illumination mode within said multi-mode LED-based illumination subsystem, the narrow-area image capture mode in said multi-mode area image formation and detection subsystem, and the first mode of said multi-mode image-processing bar code symbol reading subsystem.

9. The hand-supportable digital imaging-based bar code symbol reading device of claim 3, wherein during said manually-triggered single-attempt 1D single-read mode, when a user manually actuates said trigger switch, said system control subsystem activates the narrow-area illumination mode within the multi-mode LED-based illumination subsystem, the narrow-area image capture mode of the multi-mode area image formation and detection subsystem, and the first mode of the multi-mode image-processing based bar code symbol reading subsystem;

then, said multi-mode LED-based illumination subsystem illuminates the target object using narrow-area narrow-band illumination, said multi-mode area image formation and detection subsystem captures a narrow-area image of the target object, and said multi-mode image-processing based bar code symbol reading subsystem operates in its first mode;

the captured image is then processed by a cycle of programmed image processing performed by said multi-mode image-processing based bar code symbol reading subsystem operating in said first mode;

if a single cycle of programmed image processing results in the successful reading of a 1D bar code symbol, then the resulting symbol character data is sent to said input/output subsystem for use by the host system; and

if a single cycle of programmed image processing does not result in a successful reading of a 1D bar code symbol, then the cycle is terminated, and all subsystems are deactivated, and the bar code reader returns to its sleep mode of operation, and wait for the next event which will trigger the system into active operation.

10. The hand-supportable digital imaging-based bar code symbol reading device of claim 9, wherein said next event is the manual actuation of said trigger switch.

11. The hand-supportable digital imaging-based bar code symbol reading device of claim 3, wherein said multi-mode image-processing based bar code reading subsystem comprises a first mode, and said hand-supportable digital imaging-based bar code symbol reading device further comprises a manually-triggered multiple-attempt 1D single-read mode employing said first mode of the multi-mode image-processing based bar code symbol reading subsystem.

12. The hand-supportable digital imaging-based bar code symbol reading device of claim 11, wherein said manually-triggered multiple-attempt 1D single-read mode involves configuration of the system as follows:

disabling the IR-based object presence and range detection subsystem; and

enabling the use of said manually-actuated trigger switch, the narrow-area illumination mode within said multi-mode illumination subsystem, the narrow-area image capture mode in said image formation and detection subsystem, and the first mode of said multi-mode bar code symbol reading subsystem.

13. The hand-supportable digital imaging-based bar code symbol reading device of claim 12, wherein during said first mode of operation, the multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process a captured narrow-area frame of digital image data, without feature extraction and marking operations, so as to read a one or more bar code symbols represented in said frame of digital image data.

14. The hand-supportable digital imaging-based bar code symbol reading device of claim 13, wherein during said first mode, said multi-mode image-processing bar code symbol reading subsystem starts at the center of the image, and processes said narrow-area frame of digital image data at zero degrees and 180 degrees relative to the horizontal axis to generate bar-and-space count data, and then using said bar-and-space-count data, said multi-mode image-processing based bar code symbol reading subsystem reads the potential bar code symbol.

15. The hand-supportable digital imaging-based bar code symbol reading device of claim 14, wherein said multi-mode image-processing based bar code symbol reading subsystem during said first mode of operation, involves essentially a single stage of image processing, in which a decoding module is invoked to (i) directly process the captured narrow-area frame of digital image data, one line of scan data at a time, starting from the middle thereof, (ii) examine the zero-crossings of the processed image, (iii) create bar and space patterns therefrom, and then (iv) decode said bar and space patterns using conventional decoding algorithms.

16. The hand-supportable digital imaging-based bar code symbol reading device of claim 15, wherein during said first mode, if the bar code reading process is not successful, then said multi-mode image-processing based bar code symbol reading subsystem traverses another line of scan data within said narrow-area frame of digital image data, starting from a pixel offset which is computed by assuming that the region of interest (ROI), deemed to be the pixel height of said narrow-area frame of digital image data, has a constant maximum height along said ROI.

17. The hand-supportable digital imaging-based bar code symbol reading device of claim 11, wherein during said manually-triggered multiple-attempt 1D single-read mode, when a user manually actuates said trigger switch, said system control subsystem activates the narrow-area illumination mode within said multi-mode LED-based illumination subsystem, the narrow-area image capture mode of said multi-mode image formation and detection subsystem, and the first mode of said multi-mode image-processing based bar code symbol reading subsystem;

then, said multi-mode LED-based illumination subsystem illuminates the target object using narrow-area illumination, said multi-mode area image formation and detection subsystem captures a narrow-area image of the target object, and said multi-mode image-processing based bar code symbol reading subsystem operates in the first mode;

said captured narrow-area image is then processed by said multi-mode bar code symbol reading subsystem using the first mode;

if the single cycle of programmed image processing results in the successful reading of a 1D bar code symbol, then the resulting symbol character data is sent to said input/output subsystem for use by the host system;

if the cycle of programmed image processing does not produce a successful read, then said system control subsystem automatically enables successive cycles of illumination/capture/processing so long as said trigger switch is being pulled, and then until said multi-mode image-processing based bar code symbol reading subsystem reads a bar code symbol within a captured image of the target object; and

only thereafter, or when the user releases said trigger switch, will said bar code symbol reader return to its sleep mode of operation, and wait for the next event that will trigger the system into active operation.

18. The hand-supportable digital imaging-based bar code symbol reading device of claim 17, wherein a default timeout setting for said multi-mode image-processing based bar code symbol reading subsystem ensures that while said trigger switch is being pulled by the user, said multi-mode image-processing based bar code symbol reader will re-attempt reading a bar code symbol with the captured image until said multi-mode image-processing based bar code symbol reader either succeeds in reading a bar code symbol in said captured image, or said trigger switch is manually released.

19. The hand-supportable digital imaging-based bar code symbol reading device of claim 1, wherein said multi-mode image-processing based bar code reading subsystem comprises a first mode of operation, and said hand-supportable digital imaging-based bar code symbol reading device comprises a manually-triggered single-attempt 1D/2D single-read mode of system operation.

20. The hand-supportable digital imaging-based bar code symbol reading device of claim 19, wherein said manually-triggered single-attempt 1D/2D single-read mode programmed mode of system operation involves configuration of the system as follows:

disabling said IR-based object presence detection subsystem; and

enabling the use of said manually actuated trigger switch, the narrow-area and wide-area illumination modes within said multi-mode LED-based illumination subsystem, the narrow-area and wide-area image capture modes in said multi-mode image formation and detection subsystem, and the first mode and manual, ROI-specific and/or automatic modes of said multi-mode image-processing based bar code reading subsystem.

21. The hand-supportable digital imaging-based bar code symbol reading device of claim 19, wherein during said first mode of operation, the multi-mode image-processing based bar code symbol reading subsystem is configured to automatically process a captured narrow-area frame of digital image data, without feature extraction and marking operations, so as to read a one or more bar code symbols represented in said frame of digital image data.

22. The hand-supportable digital imaging-based bar code symbol reading device of claim 21, wherein during said first mode, said multi-mode image-processing based bar code symbol reading subsystem starts at the center of the image, and processes said narrow-area frame of digital image data at zero degrees and 180 degrees relative to the horizontal axis to generate bar-and-space count data, and then using said bar-and-space-count data generated by said filtration step, said multi-mode image-processing based bar code symbol reading subsystem reads the potential bar code symbol.

23. The hand-supportable digital imaging-based bar code symbol reading device of claim 22, wherein said multi-mode image-processing based bar code symbol reading subsystem during said first mode of operation, involves essentially a single stage of image processing, in which a decoding module is invoked to (i) directly process the captured narrow-area frame of digital image data, one line of scan data at a time, starting from the middle thereof, (ii) examine the zero-crossings of the processed image, (iii) create bar and space patterns therefrom, and then (iv) decode said bar and space patterns using conventional decoding algorithms.

24. The hand-supportable digital imaging-based bar code symbol reading device of claim 23, wherein during said first mode, if the bar code reading process is not successful, then said multi-mode image-processing based bar code symbol reading subsystem traverses another line of scan data within said narrow-area frame of digital image data, starting from a pixel offset which is computed by assuming that the region of interest (ROI), deemed to be the pixel height of said narrow-area frame of digital image data, has a constant maximum height along said ROI.

25. The hand-supportable digital imaging-based bar code symbol reading device of claim 22, wherein during said automatically-triggered multi-attempt 1D single-read mode, said device is idle until a user points said device towards a target with a bar code label, and then pulls said trigger switch;

when this event occurs, said system control subsystem activates the narrow-area illumination mode within said multi-mode LED-based illumination subsystem the narrow-area image capture mode of said multi-mode area image formation and detection subsystem, and the first mode of said multi-mode image-processing based bar code symbol reading subsystem;

then, said multi-mode LED-based illumination subsystem illuminates the target object using narrow-area illumination, said multi-mode area image formation and detection subsystem captures a narrow-area image of the target object, and said multi-mode image-processing based bar code symbol reading subsystem executes its first mode of operation;

said captured narrow-area image is then processed by said multi-mode image-processing based bar code symbol reading subsystem using the first mode;

if this single cycle of programmed image processing results in the successful reading of a 1D bar code symbol, then the resulting symbol character data is sent to the input/output subsystem for use by the host system;

if this cycle of programmed image processing does not produce a successful read, then the system control subsystem deactivates the narrow-area illumination mode within said multi-mode LED-based illumination subsystem, the narrow-area image capture mode of said multi-mode area image formation and detection subsystem, and the first mode of said multi-mode image-processing based bar code reading subsystem, and then activates the wide-area illumination mode within said multi-mode illumination subsystem, the wide-area image capture mode of the multi-mode area image formation and detection subsystem, and the manual, ROI-specific and/or automatic modes of said multi-mode image-processing based bar code reading subsystem;

then said multi-mode LED-based illumination subsystem illuminates the target object using both near-field and far-field wide-area illumination, said multi-mode area image formation and detection subsystem captures a wide-area image of the target object, and the multi-mode image-processing based bar code symbol reading subsystem executes the manual, ROI-specific or automatic mode of operation;

the captured wide-area image is then processed by said multi-mode image-processing based bar code symbol reading subsystem using the manual, ROI-specific or automatic mode;

if this single cycle of programmed image processing results in the successful reading of a 1D or 2D bar code symbol, then the resulting symbol character data is sent to said input/output subsystem for use by the host system; and

if this cycle of programmed image processing does not produce a successful read, then the system control subsystem deactivates all subsystems and then returns to its sleep mode, and waits for an event, which will cause said device to re-enter an active mode of operation.

5. The hand-supportable digital imaging-based bar code symbol reading device of 4 wherein during said first mode, said multi-mode image-processing based bar code symbol reading subsystem starts at the center of the narrow-area frame of digital image data, and filters said narrow-area frame of digital image data at zero degrees and 180 degrees relative to the horizontal axis to generate bar-and-space count data, and then using said bar-and-space-count data, said multi-mode image-processing based bar code symbol reading subsystem reads the bar code symbol.

6. The hand-supportable digital imaging-based bar code symbol reading device of claim 5, wherein said multi-mode image-processing based bar code symbol reading subsystem during said first mode, involves essentially a single stage of image processing, in which a decoding module is invoked to (i) directly process the captured narrow-area frame of digital image data, one line of scan data at a time, starting from the middle thereof, (ii) examine the zero-crossings of the processed image, (iii) create bar and space patterns therefrom, and then (iv) decode said bar and space patterns using conventional decoding algorithms.

7. The hand-supportable digital imaging-based bar code symbol reading device of claim 5, wherein during said first mode, if the bar code reading process is not successful, then said multi-mode image-processing based bar code symbol reading subsystem traverses another line of scan data within said narrow-area frame of digital image data, starting from a pixel offset which is computed by assuming that the region of interest (ROI), deemed to be the pixel height of said narrow-area frame of digital image data, has a constant maximum height along said ROI.