Laser scanning system mounted over a conveyor belt along which packages bearing bar code symbols are transported and scanned

• US 6,474,556 B2
• Filed: 02/17/1999
• Issued: 11/05/2002
• Est. Priority Date: 08/17/1994
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Dickson, LeRoy, Amundsen, Thomas, Knowles, Carl Harry, Groot, John
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US09/251,674
• Publication Number:
  US 20020050524A1
• Time in Patent Office: 1,357 Days
• Field of Search: 235/462.01, 235/472.01, 235/375, 235/462.34, 235/462.32, 235/462.25, 235/462.1, 235/462.09
• US Class Current: 235/462.24
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G02B 26/10 Scanning systems
• CPC Class Codes: G02B 26/106 having diffraction gratings as scanning elements, e.g. holographic scanners holographic optical elements G02B5/32, holography G03H
• CPC Class Codes: G06K 17/0022 arrangements or provisions for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 2207/1013 Multi-focal
• CPC Class Codes: G06K 2207/1016 Motor control or optical moving unit control
• CPC Class Codes: G06K 2207/1017 Programmable
• CPC Class Codes: G06K 2207/1018 Source control
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10603 Basic scanning using moving elements
• CPC Class Codes: G06K 7/10663 using hologram
• CPC Class Codes: G06K 7/10673 Parallel lines
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• CPC Class Codes: G06K 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/10811 : Focalisation
• 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 7/10871 : randomly oriented data-fields, code-marks therefore, e.g. concentric circles-code
• CPC Class Codes: G06K 7/10881 : constructional details of hand-held scanners
• CPC Class Codes: G06K 7/10891 : the scanner to be worn on a finger or on a wrist
• CPC Class Codes: G06K 7/109 : adaptations to make the hand-held scanner useable as a fixed scanner
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G07F 9/002 : Vending machines being part of a centrally controlled network of vending machines
• CPC Class Codes: G07G 1/0045 : with a code reader for reading of an identifying code of the article to be registered, e.g. barcode reader or radio-frequency identity [RFID] reader
• CPC Class Codes: G07G 1/0054 : with control of supplementary check-parameters, e.g. weight or number of articles

Abstract

An over-the-conveyor bar code symbol reading system for scanning bar coded packages transported through a 3-D scanning volume having a plurality of focal planes. The system comprises a conveyor belt, first and second laser scanning subsystems mounted thereabove, and a scan data processor. The first laser scanning subsystem generates a first laser scanning pattern above the conveyor belt for scanning each bar coded package transported therealong, and produces bar code position data indicative of the position of the bar code symbol on each scanned package. The second laser scanning subsystem generates and scans a second laser beam to produce a second laser scanning pattern within a 3-D scanning volume above the conveyor belt and having a plurality of focal planes. In response to scanning the transported package, the second laser scanning subsystem produces scan data indicative of the scanned bar code symbol thereon. This scan data is processed to detect each scanned bar code symbol and determine within which one of the plurality of focal planes the detected bar code symbol resides on the transported package. During operation of the system, produced bar code position data is used to automatically set the focal length of the first laser beam to spatially coincide with the focal plane within which the detected bar code symbol resides on the transported package. By virtue of the present invention, bar coded packages of varying height can now be read using a system having reduced complexity and greater compactness for mounting above space-restricted conveyor belts.

Claims

1. An automatic laser scanning bar code symbol reading system for automatically reading bar code symbols on packages transported through a 3-D scanning volume, said automatic laser scanning bar code symbol reading system comprising:

a conveyor belt along which packages bearing bar code symbols are transported;

a holographic-based bar code position detector, mounted above said conveyor belt, employing one or more laser beam sources and a holographic scanning disc for producing a first laser scanning pattern within said 3-D scanning volume, for scanning each said package transported along said conveyor belt, detecting the position of the bar code symbol on said package within said 3-D scanning volume, and automatically producing bar code position data specifying the position of the detected bar code symbol within said 3-D scanning volume; and

a laser scanning bar code symbol reader, mounted above said conveyor belt, responsive to said bar code position data, and automatically steerable as so to laser scan said detected bar code symbol, and produce scan data indicative of said detected bar code symbol, and automatically process said produced scan data so as to automatically read said detected bar code symbol and produce symbol character data representative thereof.

2. The automatic laser scanning bar code symbol reading system of claim 1, wherein said laser scanning bar code symbol reader comprises a laser scanning mechanism for automatically (i) producing a second laser scanning pattern within said 3-D scanning volume near which said bar code symbol is detected, (ii) laser scanning said detected bar code symbol using said second laser scanning pattern, and (iii) producing said scan data indicative of said scanned bar code symbol.

3. The automatic laser scanning bar code symbol reading system of claim 1, wherein said first laser scanning pattern is an omnidirectional laser scanning pattern produced within said 3-D scanning volume, for detection of the bar code symbol on each package transported through said 3-D scanning volume.

4. The automatic laser scanning bar code symbol reading system of claim 3, wherein said omnidirectional laser scanning pattern has at least four focal zones and a depth of field of at least 24 inches.

5. The automatic laser scanning bar code symbol reading system of claim 2, wherein said second laser scanning pattern is an X-bar laser scanning pattern.

6. The automatic laser scanning bar code symbol reading system of claim 1, wherein wherein said laser scanning bar code symbol reader comprises a bar code symbol decoder for automatically decode processing said produced scan data.

7. The automatic bar code symbol reading system of claim 5, wherein said bar code symbol decoder employs bar code stitching processes during said decode processing.

8. The automatic laser scanning bar code symbol reading system of claim 2, wherein said laser scanning mechanism further comprises a video buffer for collecting frames of produced scan data as said package is transported through said 3-D scanning volume and said detected bar code symbol is scanned by said second laser scanning pattern.

9. The automatic laser scanning bar code symbol reading system of claim 6, wherein said bar code symbol decoder comprises a decode computer for decode processing each frames of produced scan data collected by said video buffer.

15. The method of claim 9, wherein step (e) comprises automatically decode processing said produced scan data so as to decode said detected bar code symbol within said 3-D scanning volume.

16. The method of claim 15, wherein step (e) employs bar code stitching processes during said decode processing.

10. A method of reading bar code symbols on packages transported through a 3-D scanning volume, said method comprising the steps of:

(a) transporting packages bearing bar code symbols along a conveyor belt, over which a holographic-based bar code position detector and a laser scanning bar code symbol reader are mounted, said holographic-based bar code position detector employing one or more laser beam sources and a holographic scanning disc for producing said first laser scanning pattern within said 3-D scanning volume;

(b) using said first laser scanning pattern to scan each said package transported along said conveyor belt;

(c) detecting the position of the scanned bar code symbol using said holographic-based bar code position detector, and automatically producing bar code position data specifying the position of the detected bar code symbol within said 3-D scanning volume;

(d) using the bar code position data produced during step (c) to automatically steer said laser scanning bar code symbol reader so as to automatically laser scan said detected bar code symbol, and produce scan data indicative of said detected bar code symbol; and

(e) automatically processing said produced scan data so as to read said detected bar code symbol and produce symbol character data representative said detected bar code symbol.

11. The method of claim 10, wherein during step (d) said laser scanning bar code symbol reader comprises a laser scanning mechanism for automatically (i) producing a second laser scanning pattern within said 3-D scanning volume near which said bar code symbol is detected, (ii) scanning said detected bar code symbol using said second laser scanning pattern, and (iii) producing said scan data.

12. The method of claim 10, wherein during step (b) said first laser scanning pattern has at least four focal zones and a depth of field of at least 24 inches.

13. The method of claim 10, wherein during step (b) said first laser scanning pattern is an omnidirectional laser scanning pattern produced within said 3-D scanning volume, for detection of the bar code symbol on each package transported through said 3-D scanning volume.

14. The method of claim 11, wherein during step (d) said second laser scanning pattern is an X-bar laser scanning pattern.

17. The method of claim 11, wherein step (d) further comprises using a video buffer for collecting frames of scan data produced as said package is transported through said 3-D scanning volume and said detected bar code symbol is scanned by said second laser scanning pattern.

18. The method of claim 17, wherein step (e) comprises using a decode computer for decode processing each frames of scan data collected by said video buffer.