Hand-supportable digital-imaging based code symbol reading system supporting motion blur reduction using an accelerometer sensor

• US 8,322,622 B2
• Filed: 11/09/2010
• Issued: 12/04/2012
• Est. Priority Date: 11/09/2010
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Liu, Yong
• Primary Examiner(s): Le, Thien M.
• Assistant Examiner(s): MARSHALL, CHRISTLE I
• Application Number:
  US12/942,174
• Publication Number:
  US 20120111942A1
• Time in Patent Office: 756 Days
• Field of Search: 23546201-473
• US Class Current: 235/462.48
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning

Abstract

A digital-imaging based code symbol reading system which automatically detects hand-induced vibration when the user attempts to read one or more 1D and/or 2D code symbols on an object, and controls system operation in order to reduce motion blur in digital images captured by the hand-supportable system, whether operated in a snap-shot or video image capture mode. An accelerometer sensor is used to automatically detect hand/system acceleration in a vector space during system operation. In a first embodiment, digital image capture is initiated when the user manually depresses a trigger switch, and decode processed only when the measured acceleration of the hand-supportable housing is below predetermined acceleration threshold levels. In another embodiment, digital image capture is initiated when an object is automatically detected in the field of view of the system, and decode processed only when the measured acceleration of the hand-supportable housing is below predetermined acceleration threshold levels.

Claims

1. A digital-imaging based code symbol reading system comprising:

a hand-supportable housing having a light transmission aperture;

an image formation and detection subsystem, disposed in said hand-supportable housing, having image formation optics for producing and projecting a field of view (FOV) through said light transmission aperture and onto an area-type image detection array for detecting one or more 2D digital images of an object within said FOV, during object illumination and imaging operations;

an automatic object detection subsystem, disposed in said hand-supportable housing, for automatically detecting the presence of an object within said FOV;

an illumination subsystem, disposed in said hand-supportable housing, including a illumination array for producing a field of wide-area illumination within said FOV, and illuminating said object detected in said FOV, so that said illumination reflects off said object and is transmitted back through said light transmission aperture and onto said image detection array to detect said one or more 2D digital images of said object;

an accelerometer-based motion detection subsystem, disposed in said hand-supportable housing, for measuring the acceleration of said housing while supported in the hand of said user, and comparing said acceleration measurement with a preset acceleration threshold stored in memory aboard said hand-supportable housing;

an image capturing and buffering subsystem, disposed in said hand-supportable housing, for capturing and buffering said one or more 2D digital images detected by said image formation and detection subsystem;

a digital image processing subsystem for processing said one or more 2D digital images captured and buffered by said image capturing and buffering subsystem and reading code symbols represented in said one or more 2D digital images;

an input/output subsystem, disposed in said hand-supportable housing, for outputting processed image data to an external host system or other information receiving or, responding device; and

a system control subsystem, disposed in said hand-supportable housing, for controlling and/or coordinating said subsystems during object detection, illumination and imaging operations, in response to the results of said accelerometer-based motion detection subsystem, so as to eliminate or reduce motion blur in said one or more digital images detected by said image formation and detection subsystem;

wherein, in the event that said acceleration measurement is below said preset acceleration threshold, then said digital-imaging based code symbol reading system captures a digital image of the object in said FOV, and processes said digital image in an attempt to read any code symbol that might be graphically represented in said captured digital image;

wherein, in the event that said acceleration measurement exceeds said preset acceleration threshold, then said digital-imaging based code symbol reading system refrains from capturing a digital image of the object in said FOV, and waits for said automatic object detection subsystem to detect once again the presence of said object in said FOV;

wherein, in the event a subsequent trigger event has been detected, said digital-imaging based code symbol reading system automatically uses said accelerometer-based motion detection subsystem to make another acceleration measurement during the a current or subsequent illumination and imaging period;

wherein, in the event that said acceleration measure is below said preset acceleration threshold, then said digital-imaging based code symbol reading system captures another digital image and processes the captured digital image to read a code symbol graphically encoded in said captured digital image;

wherein, in the event that said digital-imaging based code symbol reading system successfully reads a code symbol in said captured digital image, then said digital-imaging based code symbol reading system transmits corresponding symbol character data to a said external host system or other information receiving device; and

wherein, in the event that said digital-imaging based code symbol reading system fails to successfully read a code symbol in said captured digital image, then said digital-imaging based code symbol reading system awaits for said automatic object detection subsystem to detect once again the presence of an object in said FOV.

2. The digital-imaging based code symbol reading system of claim 1, wherein said automatic object detection subsystem controls the automatic generation of a linear targeting illumination beam prior to wide-area field of view (FOV) illumination during digital imaging operations.

3. The digital-imaging based code symbol reading system of claim 1, which further comprises an illumination control subsystem, disposed in said hand-supportable housing, for controlling the operation of said illumination array within said illumination subsystem.

4. The digital-imaging based code symbol reading system of claim 1, wherein said illumination subsystem comprises an array of LEDs.

5. The digital-imaging based code symbol reading system of claim 1, wherein said accelerometer-based motion detection subsystem comprises an acceleration sensor chip mounted in said hand-supportable housing.

6. A digital-imaging based code symbol reading system comprising:

a hand-supportable housing having a light transmission aperture;

an image formation and detection subsystem, disposed in said hand-supportable housing, having image formation optics for producing and projecting a field of view (FOV) through said light transmission aperture and onto an area-type image detection array for detecting one or more 2D digital images of an object within said FOV, during object illumination and imaging operations;

a manually-actuatable trigger switch integrated said hand-supportable housing, for automatically initiating the detection of one or more 2D digital images of the object in said FOV, in response to the user of said system actuating said manually-actuatable trigger switch;

an illumination subsystem, disposed in said hand-supportable housing, including an illumination array for producing a field of wide-area illumination within said FOV, and illuminating said object detected in said FOV, so that said illumination reflects off said object and is transmitted back through said light transmission aperture and onto said image detection array to form said one or more 2D digital images of said object;

an accelerometer-based motion detection subsystem, disposed in said hand-supportable housing, for measuring the acceleration of said hand-supportable housing while supported in the hand of said user, and comparing said acceleration measurement with a preset acceleration threshold stored in memory aboard said hand-supportable housing;

an image capturing and buffering subsystem, disposed in said hand-supportable housing, for capturing and buffering said one or more 2D digital images detected by said image formation and detection subsystem;

a digital image processing subsystem for processing said one or more 2D digital images captured and buffered by said image capturing and buffering subsystem and reading code symbols represented in said one or more 2D digital images;

an input/output subsystem, disposed in said hand-supportable housing, for outputting processed image data to an external host system or other information receiving or responding device; and

a system control subsystem, disposed in said hand-supportable housing, for controlling and/or coordinating said subsystems during object detection, illumination and imaging operations, in response to the results of said accelerometer-based motion detection subsystem, so as to eliminate or reduce motion blur in said one or more digital images detected by said image formation and detection subsystem;

wherein, in the event that said acceleration measurement is below said preset acceleration threshold, then said digital-imaging based code symbol reading system captures a digital image of the object in said FOV, and processes said digital image in an attempt to read any code symbol that might be graphically represented in said captured digital image;

wherein, in the event that said acceleration measurement exceeds said preset acceleration threshold, then said digital-imaging based code symbol reading system refrains from capturing a digital image of the object in said FOV, and waits for said manually-actuatable trigger switch to be manually actuated again;

wherein, in the event that said manually-actuatable trigger switch has been manually actuated once again, said digital-imaging based code symbol reading system automatically uses said accelerometer-based motion detection subsystem to make another acceleration measurement during a current or subsequent illumination and imaging period;

wherein, in the event that said acceleration measure is below said preset acceleration threshold, then said digital-imaging based code symbol reading system captures another digital image and processes the captured digital image to read a code symbol graphically encoded in said captured digital image;

wherein, in the event that said digital-imaging based code symbol reading system successfully reads a code symbol in said captured digital image, then said digital-imaging based code symbol reading system transmits corresponding symbol character data to said external host system or other information receiving device; and

wherein, in the event that said digital-imaging based code symbol reading system fails to successfully read a code symbol in said captured digital image, then said digital-imaging based code symbol reading system awaits for said manually-actuatable trigger switch to be manually actuated once again.

7. The digital-imaging base code symbol reading system of claim 6, which further comprises an illumination control subsystem, disposed in said hand-supportable housing, for controlling the operation of said illumination array within said illumination subsystem.

8. The digital-imaging based code symbol reading system of claim 6, wherein said illumination subsystem comprises an array of LEDs.

9. The digital-imaging based code symbol reading system of claim 6, wherein said accelerometer-based motion detection subsystem comprises an acceleration sensor chip mounted in said hand-supportable housing.

10. A method of code symbol reading comprising the steps of:

(a) providing a digital-imaging based code symbol reading system having a hand-supportable housing, a field if view (FOV) defined relative to said hand-supportable housing, memory disposed in said hand-supportable housing, and an acceleration sensor disposed in said hand-supportable housing;

(b) initializing said digital-imaging based code symbol reading system and setting an acceleration threshold in said memory;

(c) upon detection of a trigger event, said digital-imaging based code symbol reading system automatically using said acceleration sensor to make an acceleration measurement during a current illumination and imaging period, and then automatically determining whether or not the current acceleration measurement exceeds said acceleration threshold set in memory;

(d)(1) in the event that said acceleration measurement made at step (c) is below said acceleration threshold, then said digital-imaging based code symbol reading system capturing a digital image of the object in said FOV, and processing said digital image in an attempt to read any code symbol that might be graphically represented in said captured digital image;

(d)(2) in the event that said acceleration measurement made at step (c) exceeds said acceleration threshold, then said digital-imaging based code symbol reading system refrains from capturing a digital image of the object in said FOV, and waits for said trigger event to be detected again;

(e) when a subsequent trigger event has been detected, said digital-imaging based code symbol reading system automatically using said acceleration sensor to make another acceleration measurement during a current or subsequent illumination and imaging period;

(f) in the event that said acceleration measure made at step (e) is below the acceleration threshold level, then said digital-imaging based code symbol reading system capturing another digital image and processing the captured digital image to read a code symbol graphically encoded in said captured digital image;

(g)(1) in the event that said digital-imaging based code symbol reading system successfully reads a code symbol in said captured digital image, then said digital-imaging based code symbol reading system transmitting corresponding symbol character data to a host system; and

(g)(2) in the event that said digital-imaging based code symbol reading system fails to successfully read a code symbol in said captured digital image, then said digital-imaging based code symbol reading system awaits for the occurrence of a subsequent trigger event in said digital-imaging based code symbol reading system.

11. The method of claim 10, wherein said trigger event is manually initiated by manually depressing a trigger switch disposed on said hand-supportable housing when an, object is present in said FOV.

12. The method of claim 10, wherein said trigger event is automatically initiated by automatic detection of an object in said FOV.

13. The method of claim 10, wherein said code symbol is a code symbol selected from the group consisting of 1D bar code symbologies, 2D bar code symbologies, and data matrix symbologies.

14. A method of code symbol reading comprising the steps of:

(a) providing a digital-imaging based code symbol reading system having a hand-supportable housing, a field if view (FOV) defined relative to said hand-supportable housing, memory disposed in said hand-supportable housing, and an acceleration sensor disposed in said hand-supportable housing;

(b) initializing said digital-imaging based code symbol reading system and setting an acceleration threshold in said memory;

(c) upon detection of a trigger event, said digital-imaging based code symbol reading system automatically using said acceleration sensor to make an acceleration measurement during a current illumination and imaging period, and then automatically determining whether or not the current acceleration measurement exceeds said acceleration threshold set in memory;

(d)(1) in the event that said acceleration measurement made at step (c) is below said acceleration threshold, then said digital-imaging based code symbol reading system capturing a digital image of the object in said FOV, and processing said digital image in an attempt to read any code symbol that might be graphically represented in said captured digital image;

(d)(2) in the event that said acceleration measurement made at step (c) exceeds said acceleration threshold, then said digital-imaging based code symbol reading system refrains from capturing a digital image of the object in said FOV, and waits for said trigger event to be detected again;

(e) when a first subsequent trigger event has been detected, said digital-imaging based code symbol reading system automatically using said acceleration sensor to make another acceleration measurement during a current or subsequent illumination and imaging period;

(f) in the event that said acceleration measure made at step (e) is below the acceleration threshold level, then said digital-imaging based code symbol reading system capturing another digital image and processing the captured digital image to read a code symbol graphically encoded in said captured digital image;

(g)(1) in the event, that said digital-imaging based code symbol reading system successfully reads a code symbol in said captured digital image, then said digital-imaging based code, symbol reading system transmitting corresponding symbol character data to a host system;

(g)(2) in the event that said digital-imaging based code symbol reading system does not successfully read a code symbol in said captured digital image, then said digital-imaging based code symbol reading system processes said digital image in an effort to reduce motion blur prior to image-based code symbol decoding, and upon successful reading of a code symbol graphically represented in said captured digital image, said digital-imaging based code symbol reading system returns to step (c) and awaits for the occurrence of a second subsequent trigger event in said digital-imaging based code symbol reading system.

15. The method of claim 14, wherein said trigger event is manually initiated by manually depressing a trigger switch disposed on said hand-supportable housing when an object is present in said FOV.

16. The method of claim 14, wherein during step (c) said trigger event is automatically initiated by automatic detection of an object in said FOV;

wherein during step (e), said first subsequent trigger event is detected by automatic detection of said object in said FOV; and

wherein during step (g)(3), said second subsequent trigger event is detected by automatic detection of said object present in said FOV.

17. The method of claim 14, wherein said code symbol is a code symbol selected from the group consisting of 1D bar code symbologies, 2D bar code symbologies, and data matrix symbologies.