Method of locating imaged bar codes for an imaging-based bar code reader

• US 7,261,238 B1
• Filed: 05/26/2006
• Issued: 08/28/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Carlson, Brad, Pang, Robert James, Lackemann, Thomas E.
• Primary Examiner(s): Lee; Michael G.
• Assistant Examiner(s): Vo; Tuyen Kim
• Application Number:
  US11/441,728
• Time in Patent Office: 459 Days
• Field of Search: 235/462.25, 235/462.06, 235/462.14, 235/462.24, 235/454
• US Class Current: 235/462.08
• 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 7/10861 sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48
• CPC Class Codes: G06K 7/1093 sensing, after transfer of the image of the data-field to an intermediate store, e.g. storage with cathode ray tube
• CPC Class Codes: G06K 7/1443 locating of the code in an image

Abstract

A method of locating an imaged bar code in a captured image frame for an imaging-based bar code reader. The steps of the method include: a) determining a mode of operation of the reader; b) if the reader is being operated in a hand-held mode of operation, utilizing a first method of locating an imaged bar code; and c) if the reader is being operated in a fixed position mode, utilizing a second method of locating an imaged bar code. The first method of locating an imaged bar code includes searching for an imaged bar code commencing at a starting location near a geographic center of the selected image frame. The second method of locating an imaged bar code includes determining a location corresponding to movement in a selected image frame of the series of image frames and searching for an imaged bar code commencing at the movement location.

Claims

1. A method of locating an imaged bar code in a captured image frame for an imaging-based bar code reader, the steps of the method comprising:

determining a mode of operation of the reader;

if the reader is being operated in a hand-held mode of operation, utilizing a first method of locating the imaged bar code wherein the first method of locating the imaged bar code includes the steps of;

selecting a captured image frame;

searching for the imaged bar code commencing at a starting location near a geographic center of the selected image frame; and

if no imaged bar code is found at the starting location, utilizing a search pattern to search outwardly from the starting location until the imaged bar code is found; and

if the reader is being operated in a fixed position mode, utilizing a second method of locating the imaged bar code wherein the second method of locating the imaged bar code includes the steps of;

analyzing a series of captured image frames for changes in the series of captured image frames indicative of a movement of an object in the series of captured image frames;

determining a location corresponding to the movement in a selected image frame of the series of captured image frames;

searching for the imaged bar code commencing at the movement location within the selected image frame; and

if no imaged bar code is found at the movement location, utilizing a search pattern to search outwardly from the movement location until the imaged bar code is found.

2. The method of claim 1 wherein in the first method, the search pattern searches outwardly in a spiral pattern from the starting location.

3. The method of claim 1 wherein the steps of the second method further include determining a direction of the movement of the object in the series of captured image frames and, if no imaged bar code is found at the movement location, the search pattern searches outwardly from the movement location in the direction of the movement of the object.

4. An imaging-based bar code reader adapted to be used in a hand-held mode of operation and a fixed position mode of operation, the reader comprising:

an imaging system including a sensor array for imaging a target bar code and generating captured image frames of a field of view of the imaging system;

a decoding system for decoding an image of the target bar code located within a captured image frame;

the decoding system utilizing a first method of locating an imaged bar code in the captured image frame if the reader is operated in the hand-held mode, the first method of locating an imaged bar code including the steps of;

selecting a captured image frame;

searching for the imaged bar code commencing at a starting location near a geographic center of the selected image frame; and

if no imaged bar code is found at the starting location, utilizing a search pattern to search outwardly from the starting location until the imaged bar code is found; and

the decoding system utilizing a second method of locating the imaged bar code in a captured image frame if the reader is operated in the stationary mode, the second method of locating the imaged bar code includes the steps of;

analyzing a series of captured image frames for changes in the series of captured image frames indicative of a movement of an object in the series of captured image frames;

determining a location corresponding to the movement in a selected image frame of the series of captured image frames;

searching for the imaged bar code commencing at the movement location within the selected image frame; and

if no imaged bar code is found at the movement location, utilizing a search pattern to search outwardly from the movement location until the imaged bar code is found.

5. The bar code reader of claim 4 wherein in the first method, the search pattern searches outwardly in a spiral pattern from the starting location.

6. The bar code reader of claim 4 wherein the steps of the second method further include determining a direction of the movement of the object in the series of captured image frames and, if no imaged bar code is found at the movement location, the search pattern searches outwardly from the movement location in the direction of the movement of the object.

7. The bar code reader of claim 4 wherein the reader includes a portable housing and a docking station adapted to receive the portable housing, the housing being removable from the docking station when the reader is used in the hand-held mode and to be received in the docking station when the reader is used in the fixed position mode.

8. The bar code reader of claim 7 wherein the docking station includes a planar lower surface adapted to be positioned on a counter to facilitate operation of the reader in the fixed position mode.

9. The bar code reader of claim 7 wherein the docking station and portable housing including an electrical interface to electrically couple circuitry located in the housing and circuitry located in the docking station when the housing is received in the docking station.

10. The bar code reader of claim 4 wherein the imaging system and the decoding system are integral.

11. The bar code reader of claim 4 wherein the imaging system includes focusing optics for focusing illumination from the field of view onto the sensor array.

12. The bar code reader of claim 4 wherein the sensor array of the imaging system is a 2D sensor array.

13. The bar code reader of claim 11 wherein the imaging assembly includes a camera assembly disposed within a camera assembly housing, the camera assembly supporting the focusing optics and the sensor array.

14. The bar code reader of claim 4 further including an illumination system to direct illumination along the field of view of the imaging system.

15. The bar code reader of claim 4 further including an aiming system to facilitate aiming of the reader at the target bar code in the hand-held mode of operation.

16. The bar code reader of claim 15 wherein, in the first method, the selected image frame is an image frame acquired when the aiming system was turned off.

17. The bar code reader of claim 4 further including an aiming system to facilitate positioning the target bar code within the field of view of the imaging system in the fixed position mode of operation.

18. A decoding system for use with an imaging-based bar code reader adapted to be used in a hand-held mode of operation and a fixed position mode of operation, the decoding system comprising:

circuitry for decoding an image of the target bar code located within a captured image frame;

the decoding system utilizing a first method of locating the imaged bar code in the captured image frame if the reader is operated in the hand-held mode, the first method of locating an imaged bar code including the steps of;

selecting a captured image frame;

searching for the imaged bar code commencing at a starting location near a geographic center of the selected image frame; and

if no imaged bar code is found at the starting location, utilizing a search pattern to search outwardly from the starting location until the imaged bar code is found; and

the decoding system utilizing a second method of locating the imaged bar code in a captured image frame if the reader is operated in the stationary mode, the second method of locating an imaged bar code includes the steps of;

analyzing a series of captured image frames for changes in the series of captured image frames indicative of a movement of an object in the series of captured image frames;

determining a location corresponding to the movement in a selected image frame of the series of captured image frames;

searching for the imaged bar code commencing at the movement location within the selected image frame; and

if no imaged bar code is found at the movement location, utilizing a search pattern to search outwardly from the movement location until the imaged bar code is found.

19. The decoding system of claim 18 wherein in the first method, the search pattern searches outwardly in a spiral pattern from the starting location.

20. The decoding system of claim 18 wherein the steps of the second method further include determining a direction of the movement of the object in the series of captured image frames and, if no imaged bar code is found at the movement location, the search pattern searches outwardly from the movement location in the direction of the movement of the object.

21. Computer-readable media having computer-executable instructions for performing a method of locating an imaged bar code in a captured image frame for an imaging-based bar code reader, the steps of the method comprising:

determining a mode of operation of the reader;

if the reader is being operated in a hand-held mode of operation, utilizing a first method of locating the imaged bar code wherein the first method of locating the imaged bar code includes the steps of;

selecting a captured image frame;

searching for the imaged bar code commencing at a starting location near a geographic center of the selected image frame; and

if no imaged bar code is found at the starting location, utilizing a search pattern to search outwardly from the starting location until the imaged bar code is found; and

if the reader is being operated in a fixed position mode, utilizing a second method of locating the imaged bar code wherein the second method of locating the imaged bar code includes the steps of;

analyzing a series of captured image frames for changes in the series of captured image frames indicative of a movement of an object in the series of captured image frames;

determining a location corresponding to the movement in a selected image frame of the series of captured image frames;

searching for the imaged bar code commencing at the movement location within the selected image frame; and

if no imaged bar code is found at the movement location, utilizing a search pattern to search outwardly from the movement location until the imaged bar code is found.

22. An imaging-based bar code reader adapted to be used in a hand-held mode of operation and a fixed position mode of operation, the reader comprising:

means for imaging a target bar code and generating captured image frames of a field of view of the imaging system;

means for decoding an image of the target bar code located within a captured image frame;

the means for decoding utilizing a first method of locating the imaged bar code in a captured image frame if the reader is operated in the hand-held mode, the first method of locating the imaged bar code including the steps of;

selecting a captured image frame;

searching for the imaged bar code commencing at a starting location near a geographic center of the selected image frame; and

if no imaged bar code is found at the starting location, utilizing a search pattern to search outwardly from the starting location until the imaged bar code is found; and

the means for decoding utilizing a second method of locating the imaged bar code in a captured image frame if the reader is operated in the stationary mode, the second method of locating the imaged bar code includes the steps of;

analyzing a series of captured image frames for changes in the series of captured image frames indicative of a movement of an object in the series of captured image frames;

determining a location corresponding to the movement in a selected image frame of the series of captured image frames;

searching for the imaged bar code commencing at the movement location within the selected image frame; and

if no imaged bar code is found at the movement location, utilizing a search pattern to search outwardly from the movement location until the imaged bar code is found.