Automatically-triggered digital video-imaging based code symbol reading system supporting dynamically controlled object illumination and digital video-imaging operations

• US 20080061144A1
• Filed: 06/12/2007
• Published: 03/13/2008
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: Anatoly Kotlarsky, Daniel Hu, Ka Au, Mark Meagher, Michael Veksland, Richard Hou, Timothy Good, Xiaoxum Zhu
• Original Assignee: Anatoly Kotlarsky, Daniel Hu, Ka Au, Mark Meagher, Michael Veksland, Richard Hou, Timothy Good, Xiaoxum Zhu
• Inventors: Zhu, Xiaoxum, Veksland, Michael, Good, Timothy, Kotlarsky, Anatoly, Hou, Richard, Meagher, Mark, Hu, Daniel, Au, Ka
• Granted Patent: US 7,712,666 B2
• Time in Patent Office: Days
• US Class Current: 235/462.11
• CPC Class Codes: G06K 7/10683 Arrangement of fixed elements
• 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 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• 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

Abstract

An automatic automatically-triggered digital video-imaging based code symbol reading system for use in point of sale (POS) environments, employing an adaptive control process involving the real-time analysis of the exposure quality of captured frames of digital image data and the real-time reconfiguration of system control parameters (SCPs) based on the results of such exposure quality analysis. By virtue of the present invention, the system enables the reliable reading of code symbols graphically represented in digital images, under demanding point-of-sale lighting conditions and other challenging environments.

Claims

1. Automatically-triggered digital video-imaging based code symbol reading system supporting dynamically controlled object illumination and digital video-imaging operations, said automatically-triggered digital video-imaging based code symbol reading system comprising:

a housing having an imaging window;

a digital image formation and detection subsystem, disposed within a housing, and having image formation optics for projecting a field of view (FOV) from an area-type image detection array, through said imaging window, and upon the object to be imaged during object illumination and video-imaging operations, and said area-type image detection array detecting frames of digital video image data of the object during said object illumination and video-imaging operations;

an illumination subsystem, disposed within said housing, and having an illumination array for producing and projecting a field of illumination within said FOV during said object illumination and video-imaging operations;

an object detection subsystem, disposed in said housing, for automatically detecting the presence of the object in said FOV, and generating a trigger signal indicative of the presence of the object within said FOV;

an automatic illumination control subsystem, disposed within said housing, for automatically controlling said illumination array during said object illumination and video-imaging operations;

a digital video frame capturing and buffering subsystem, disposed within said housing, for capturing and buffering said frames of digital video image data in memory, during said object illumination and video-imaging operations;

a digital video image processing subsystem, disposed in said housing, for processing said frames of digital video image data and reading one or more 1D and/or 2D code symbols graphically represented in said frames of digital video image data, and producing symbol character data representative of said read one or more 1D and/or 2D code symbols;

an input/output subsystem, disposed in said housing, for transmitting said symbol character data to an external host system or other information receiving or responding device; and

a system control subsystem, disposed in said housing, responsive to said trigger signal, and for managing in memory, exposure quality threshold (EQT) parameters and said SCPs, and controlling and/or coordinating the operation of said subsystems above.

2. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, wherein during system initialization, said digital video-imaging based code symbol reading system (i) sets an initial set of system control parameters (SCP), (ii) sets a SCP reconfiguration (SCPR) flag to a first value, indicating that said digital video-imaging based code symbol reading system should not be reconfigured, and (iii) calculates and sets exposure quality threshold (EQT) parameters in said memory.

3. The automatically-triggered digital video-imaging based code symbol reading system of claim 2, wherein upon the generation of said trigger signal, the following sequence of operations are performed:

(1) in the event that said SCPR flag is set to a second value, indicative that said digital video-imaging based code symbol reading system should be reconfigured, then said digital video-imaging based code symbol reading system is automatically reconfigured using a new set of SCPs;

otherwise, said digital video-imaging based code symbol reading system is maintained in its current configuration using the current set of SCPs;

(2) said object in said FOV is illuminated with illumination produced from said illumination subsystem using the method of illumination indicated by the current set of SCPs, and one or more frames of digital video image data of the illuminated object are captured and buffered;

(3) said one or more frames of captured digital video image data are analyzed for exposure quality;

(4) in the event that the measured exposure quality during Step (3) does not satisfy the exposure quality threshold (EQT) parameters, then a new set of SCPs are calculated and said SCPR flag is set to said second value, indicating that said digital video-imaging based code symbol reading system should be reconfigured prior to acquiring one or more frames of digital video image data during the next video image acquisition cycle;

otherwise, said digital video-imaging based code symbol reading system is maintained in the current configuration using the current set of SCPs;

(5) said digital video image processing subsystem processes said one or more frames of digital video image data captured during Step (3) so as to read one or more bar code symbols graphically represented in said one or more frames of digital video image data;

(6) in the event that said digital video image processing subsystem fails to read one or more bar code symbols in said one or more frames of digital video image data and said digital video image processing subsystem has determined that said exposure quality does not satisfy the exposure quality threshold parameters, then said digital video-imaging based code symbol reading system returns to step (1) above;

(7) in the event that said digital video image processing subsystem successfully reads a barcode symbol in said one or more frames of digital video image data, then said input/output subsystem transmits symbol character data and/or said digital image to a host system; and

(8) if necessary, said input/output subsystem transmits said digital image to said host system, or stores said digital image in memory aboard said digital video-imaging based code symbol reading system.

4. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, wherein the operation of said digital image formation and detection subsystem is characterized by a first group of system control parameters selected from the group consisting of:

(i) a shutter mode parameter, (ii) an electronic gain parameter, (iii) a programmable exposure time parameter, for each block of pixels detected in said image detection array, (iv) an image capture mode parameter, and (v) an image capture control parameter.

5. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, wherein the operation of said illumination subsystem is characterized by a second group of system control parameters selected from the group consisting of:

(i) an illumination mode, (ii) an automatic illumination control parameter, and (iii) an illumination field type parameter.

6. The automatically-triggered digital video-imaging based code symbol reading system of claim 2, wherein, said shutter mode of image sensor parameter is a video mode parameter.

7. The automatically-triggered digital video-imaging based code symbol reading system of claim 5, wherein said illumination mode parameter is selected from the group consisting of OFF, continuously ON, and strobe/flash values.

8. The automatically-triggered digital video-imaging based code symbol reading system of claim 5, wherein said automatic illumination control parameter is selected from the group consisting of ON and OFF values.

9. The automatically-triggered digital video-imaging based code symbol reading system of claim 5, wherein said illumination field type parameter is selected from the group consisting of narrow-area field of illumination, and wide-area field of illumination.

10. The automatically-triggered digital video-imaging based code symbol reading system of claim 5, wherein said image capture mode is selected from the group consisting of narrow-area image capture, and wide-area image capture.

11. The automatically-triggered digital video-imaging based code symbol reading system of claim 5, wherein said image capture control parameter a video frame parameter.

12. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, wherein said exposure quality threshold (EQT) parameters are selected from the group consisting of brightness level and image saturation.

13. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, wherein said object detection subsystem comprises an automatic IR-based object detection subsystem which automatically detects the presence of the object within said FOV, and generates said triggering signal in response thereto.

14. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, which is realized in the form of a hand-supportable digital video-imaging based code symbol reader.

15. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, which is realized in the form of a presentation-type digital video-imaging based code symbol reader.

16. The automatically-triggered digital video-imaging based code symbol reading system of claim 1, which is realized in the form of a digital video-imaging based code symbol reading engine installed within said host system.