Digital imaging system employing the spectral-mixing of visible and invisible laser illumination during object imaging operations

• US 20080121719A1
• Filed: 10/29/2007
• Published: 05/29/2008
• Est. Priority Date: 11/24/2000
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Veksland, Michael, Ren, Jie, Knowles, C. Harry, Xian, Tao, Liu, Yong, Good, Timothy, Giordano, Patrick, Schmidt, Mark, Kotlarsky, Anatoly, Tao, Xi, Liu, JiBin, Essinger, Steven, Gardner, John, Kearney, Sean, Ellis, Duane, Ciarlante, Nicholas, Hernandez, Mark, Zhuo, Ming, Furlong, John A.
• Granted Patent: US 7,588,188 B2
• Time in Patent Office: Days
• US Class Current: 235/462.42
• CPC Class Codes: A47F 9/046 Arrangement of recording means in or on check-out counters record carriers or readers per se G06K
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/10544 by scanning of the records by radiation in the optical part of the electromagnetic spectrum
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10613 by rotation, e.g. polygon
• CPC Class Codes: G06K 7/10623 Constructional details
• CPC Class Codes: G06K 7/10693 for omnidirectional scanning
• CPC Class Codes: G06K 7/10712 Fixed beam scanning
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10782 Slot readers
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• 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: G06Q 20/208 Input by product or record sensing, e.g. weighing or scanner processing
• CPC Class Codes: G06Q 30/06 Buying, selling or leasing transactions
• CPC Class Codes: G06V 10/141 Control of illumination
• CPC Class Codes: G07G 1/0036 Checkout procedures
• 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 3/00 : Alarm indicators, e.g. bells
• CPC Class Codes: G07G 3/006 : False operation

Abstract

A digital image capturing and processing system including an image formation and detection (IFD) subsystem having a linear image sensing array and optics providing a field of view (FOV) on the linear image sensing array. A spectral-mixing based illumination subsystem produces a first field of visible laser illumination produced from an array of visible VLDs, and a second field of invisible laser illumination produced from an array of IR laser diodes (LDs) that spatially overlap and intermix with each other so as to produce a composite planar laser illumination beam which is substantially with the FOV of the linear image sensing array. An illumination control subsystem controls the spectral mixing of visible and invisible laser illumination produced from the spectral-mixing based illumination subsystem, by adaptively controlling the relative power ratio (VIS/IR) of said fields of visible and invisible laser illumination. An image capturing and buffering subsystem captures and buffers images from the image sensing array. An automatic object detection subsystem automatically detects the an object moving through at least a portion of the FOV of the linear image sensing array, and generation a control activation signal. A control subsystem, responsive to the control activation signal, controls the operations of the subsystems within the illumination and imaging station.

Claims

1. A digital image capturing and processing system comprising:

an image formation and detection (IFD) subsystem having a linear image sensing array and optics providing a field of view (FOV) on said linear image sensing array;

an spectral-mixing based illumination subsystem producing a first field of visible laser illumination produced from an array of visible VLDs, and a second field of invisible laser illumination produced from an array of IR laser diodes (LDs) that spatially overlap and intermix with each other so as to produce a composite planar laser illumination beam which is substantially with the FOV of said linear image sensing array;

an illumination control subsystem for controlling the spectral mixing of visible and invisible laser illumination produced from said spectral-mixing based illumination subsystem, by adaptively controlling the relative power ratio (VIS/IR) of said fields of visible and invisible laser illumination;

an image capturing and buffering subsystem for capturing and buffering images from the image sensing array;

an automatic object detection subsystem for automatically detecting the an object moving through at least a portion of the FOV of said linear image sensing array, and generation a control activation signal; and

a control subsystem, responsive to said control activation signal, for controlling the operations of the subsystems within the illumination and imaging station.

2. The digital image capturing and processing system of claim 1, wherein said relative power ratio (VIS/IR) is adaptively controlled so as to optimize the relative power ratio (VIS/IR) in effort to achieve sufficient image contrast in captured digital images to ensure satisfactory image processing.

3. The digital image capturing and processing system of claim 1, wherein said illumination control subsystem adaptively controls the relative power ratio (VIS/IR) of visible laser illumination and invisible laser illumination during system operation by controlling the current supplied to said VLDs and IR-LDs during object illumination and imaging operations.

4. The digital image capturing and processing system of claim 3, wherein said current supplied to said VLDs and IR-LDs is controlled, during object illumination and imaging operations, by the following process:

(i) driving said VLDs and IR-LDs with a predetermined/default values of drive currents so as to illuminate the object with a spectral mixture of illumination;

(ii) capturing one or more digital images of the illuminated object and measuring image contrast quality so as to generate feedback or control data; and

(iii) using this feedback or control data to dynamically generate the necessary values for the adjusted said VLD and IR-LD current control signals that are used to drive the diodes and produce an optimal mixture of illumination during object illumination and imaging operations.

5. The digital image capturing and processing system of claim 1, wherein said automatic object detection subsystem comprises an imaging-based object motion detection subsystem including an area-type image acquisition subsystem and a digital signal processing chip to support digital image capture and processing operations required for real-time object motion detection.

6. The digital image capturing and processing system of claim 1, wherein said 1D and/or 2D code symbols are selected from the group consisting of 1D bar code symbols, 2D bar code symbols and 2D data matrix symbols.

7. The digital image capturing and processing system of claim 6, wherein said capturing one or more digital images of the illuminated object and measuring image contrast quality is carried out within said digital image processing subsystem.