System and method for decoding optical codes read by an imager-based optical code reader

• US 20060022052A1
• Filed: 07/29/2004
• Published: 02/02/2006
• Est. Priority Date: 07/29/2004
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Patel, Mehul, Pang, Robert James
• Granted Patent: US 7,097,102 B2
• Time in Patent Office: Days
• US Class Current: 235/462.260
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10752 Exposure time control

Abstract

A system and method for reading an optical code is provided. The method comprises the steps of imaging at least one target, including acquiring and processing image data corresponding to a series of at least one frame; storing image data corresponding to respective acquired frames of the at least one frame, including at least image data corresponding to a current frame (Frame(N)) and image data corresponding to a previous frame (Frame(N−1)); receiving an actuation signal during Frame(N) indicating initiation of a read operation; retrieving at least a portion of the image data corresponding to Frame (N−1); and performing a decode operation on the retrieved image data.

Claims

1. An optical code reader system comprising:

an imaging module for imaging at least one target, including acquiring and processing image data corresponding to a series of at least one frame;

at least one storage medium for storing image data corresponding to respective acquired frames of the at least one frame, including at least image data corresponding to a current frame (Frame(N)) and image data corresponding to a previous frame (Frame(N−

1)); and

a processor assembly including at least one processor for receiving an actuation signal during Frame(N) indicating initiation of a read operation, the processor assembly comprising;

a frame grabber module executable on the at least one processor for retrieving at least a portion of the image data corresponding to Frame (N−

1) from the at least one storage medium; and

a decoder module executable on the at least one processor for performing a decode operation on the retrieved image data.

2. The optical code reader in accordance with claim 1, further comprising:

an ambient light sensor assembly for sensing at least one property of ambient light and generating an ambient light signal corresponding to the sensing;

wherein the processor assembly further comprises a parameter adjuster module executable on the at least one processor for analyzing the ambient light signal and adjusting settings of at least one parameter of the imaging module used for at least one of acquiring and processing the image data in accordance with the analysis.

3. The optical code reader in accordance with claim 2, wherein the parameter adjuster module performs at least one of the analyzing and adjusting substantially simultaneously with at least one of the retrieving by the frame grabber module and the performing a decode operation by the decode module.

4. The optical code reader in accordance with claim 2, wherein the imager module includes an image sensor array for sensing incident light reflected from a target image and generating a plurality of image signals corresponding to the sensing, and at least one of gain circuitry for processing gain of the plurality of image signals in accordance with a gain parameter that determines the gain, exposure circuitry for controlling exposure time of the image sensor array in accordance with an exposure parameter that determines the exposure time, and an illumination assembly for providing illumination during the sensing in accordance with at least one of an illumination intensity parameter that determines the intensity of the illumination, and an illumination duration parameter that determines the duration of the illumination;

and

wherein the at least one parameter includes at least one of the gain parameter, the exposure parameter, the illumination intensity parameter and the illumination duration parameter.

5. The optical code reader in accordance with claim 1, wherein performance of at least one of retrieving at least a portion of the image data corresponding to Frame (N−

1) from the at least one storage medium and performing the decode operation on the retrieved image data is performed before the beginning of Frame(N+1).

6. The optical code reader in accordance with claim 1, wherein:

the processor assembly further performs at least one iteration of;

determining if the decode operation performed on the previously retrieved image data was successful; and

if not;

the frame grabber module retrieves different image data than the previously retrieved image data from the at least one storage medium, and the decoder module performs a decode operation on the retrieved different image data.

7. The optical code reader in accordance with claim 2, wherein at least one of the analyzing the ambient light signal and adjusting the at least one parameter is performed before the beginning of Frame(N+1).

8. The optical code reader in accordance with claim 1, wherein a successful decode operation is performed before the beginning of Frame(N+2).

9. The optical code reader in accordance with claim 2, wherein a successful decode operation is performed on image data that was at least one of acquired and processed in accordance with the adjusted at least one parameter before the beginning of Frame(N+4).

10. The optical code reader in accordance with claim 2, wherein prior to initiating the read operation, the settings for the at least one parameter are initialized to default settings which are optimized for at least one of acquiring and processing image data in a state of motion.

11. An optical code reader device comprising:

an imaging module for imaging at least one target, including acquiring and processing image data corresponding to a series of at least one frame;

at least one storage medium for storing image data corresponding to respective acquired frames of the at least one frame, including at least image data corresponding to a current frame (Frame(N)) and image data corresponding to a previous frame (Frame(N−

1)); and

a processor assembly including at least one processor for receiving an actuation signal during Frame(N) indicating initiation of a read operation, the processor assembly comprising;

a frame grabber module executable on the at least one processor for retrieving at least a portion of the image data corresponding to Frame (N) from the at least one storage medium; and

a decoder module executable on the at least on processor for performing a decode operation on the retrieved image data.

12. The optical code reader in accordance with claim 11, wherein the frame grabber module retrieves the data corresponding to Frame(N−

1) and the decoder module performs a decode operation on the retrieved image data corresponding to Frame(N−

1).

13. A method for reading an optical code comprising the steps of:

imaging at least one target, including acquiring and processing image data corresponding to a series of at least one frame;

storing image data corresponding to respective acquired frames of the at least one frame, including at least image data corresponding to a current frame (Frame(N)) and image data corresponding to a previous frame (Frame(N−

1));

receiving an actuation signal during Frame(N) indicating initiation of a read operation;

retrieving at least a portion of the image data corresponding to Frame (N−

1); and

performing a decode operation on the retrieved image data.

14. The method in accordance with claim 13, further comprising the steps of:

sensing at least one property of ambient light;

generating an ambient light signal corresponding to the sensing;

analyzing the ambient light signal; and

adjusting settings of at least one parameter of the imaging module used for at least one of acquiring and processing the image data in accordance with the analyzing.

15. The method in accordance with claim 14, further comprising the steps of:

sensing incident light reflected from a target image;

generating a plurality of image signals corresponding to the sensing; and

at least one of processing gain of the plurality of image signals in accordance with a gain parameter that determines the gain, controlling exposure time of for sensing the reflected light in accordance with an exposure parameter that determines the exposure time, generating illumination during the sensing in accordance with at least one of an illumination intensity parameter that determines the intensity of the illumination and an illumination duration parameter that determines the duration of the illumination;

wherein the at least one parameter includes at least one of the gain parameter, the exposure parameter, the illumination intensity parameter and the illumination duration parameter.

16. The method in accordance with claim 13, further comprising the step of determining if the decode operation performed on the image data corresponding to Frame(N−

1) was successful; and

if not;

retrieving at least a portion of the image data corresponding to Frame(N); and

performing a decode operation on the retrieved image data corresponding to Frame(N).

17. The method in accordance with claim 13, wherein the performing a decode operation step is performed successfully before the beginning of Frame(N+1).

18. The method in accordance with claim 14, wherein the performing a decode operation step is performed successfully on image data that was at least one of acquired and processed in accordance with the adjusted at least one parameters before the beginning of Frame(N+3).

19. The method in accordance with claim 14, further comprising the step of prior to initiating the read operation, initializing settings for the at least one parameter to default settings which are optimized for at least one of acquiring and processing image data in a state of motion.

20. The method in accordance with claim 14, wherein at least one of the analyzing and adjusting steps is performed before the beginning of Frame(N+2).

21. An optical code reading device comprising:

an imaging module for imaging at least one target, including acquiring and processing image data corresponding to a series of at least one frame, wherein at least one of the acquiring and processing is performed in accordance with at least one adjustable parameter;

an ambient light sensor assembly for sensing at least one property of ambient light and generating an ambient light signal that corresponds to the sensing; and

a processor assembly including at least one processor, wherein the processor assembly comprises;

at least one module executable on the at least one processor for receiving an actuation signal during Frame(N) indicating initiation of a read operation, and in response to receipt of the actuation signal accessing at least a portion of image data corresponding to a frame of the series of at least one frame and decoding the accessed image data; and

a parameter adjuster module executable on the at least one processor for in response to receipt of the actuation signal, analyzing the ambient light signal in accordance with the analysis adjusting settings of the at least one adjustable parameter before the beginning of Frame(N+2).

22. The optical code reader device according to claim 21, wherein the parameter adjustment module adjusts the settings of the at least one adjustable parameter before the beginning of Frame(N+1).

23. The optical code reader device according to claim 21, wherein the imager module includes an image sensor array for sensing incident light reflected from a target image and generating a plurality of image signals corresponding to the sensing and at least one of gain circuitry for processing gain of the plurality of image signals in accordance with a gain parameter that determines the gain, exposure circuitry for controlling exposure time of the image sensor array in accordance with an exposure parameter that determines the exposure time, and an illumination assembly for providing illumination during the sensing in accordance with at least one of an illumination intensity parameter that determines the intensity of the illumination, and an illumination duration parameter that determines the duration of the illumination;

and

wherein the at least one adjustable parameter includes at least one of the gain parameter, the exposure parameter, the illumination intensity parameter and the illumination duration parameter.

24. A method for imaging an optical code comprising the steps of:

imaging at least one target, including acquiring and processing image data corresponding to a series of at least one frame, wherein at least one of the acquiring and processing is performed in accordance with at least one adjustable parameter;

sensing at least one property of ambient light;

generating an ambient light signal corresponding to the sensing;

receiving an actuation signal during Frame(N) indicating initiation of a read operation;

accessing at least a portion of image data corresponding to a frame of the series of at least one frame and decoding the accessed image data in response to receipt of the actuation signal;

analyzing the ambient light signal in response to receipt of the actuation signal; and

adjusting settings of the at least one adjustable parameter in accordance with results of the analyzing step before the beginning of Frame(N+2).

25. The method according to claim 24, wherein adjusting settings step is performed before the beginning of Frame(N+1).

26. The method in accordance with claim 24, further comprising the steps of:

sensing incident light reflected from a target image;

generating a plurality of image signals corresponding to the sensing; and

at least one of processing gain of the plurality of image signals in accordance with a gain parameter that determines the gain, controlling exposure time of for sensing the reflected light in accordance with an exposure parameter that determines the exposure time, generating illumination during the sensing in accordance with at least one of an illumination intensity parameter that determines the intensity of the illumination and an illumination duration parameter that determines the duration of the illumination;

wherein the at least one adjustable parameter includes at least one of the gain parameter, the exposure parameter, the illumination intensity parameter and the illumination duration parameter.