Bar code reading device with global electronic shutter control

• US 7,568,628 B2
• Filed: 03/11/2005
• Issued: 08/04/2009
• Est. Priority Date: 03/11/2005
• Status: Active Grant

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: Havens, William H., Wang, Ynjiun
• Primary Examiner(s): Lee; Michael G
• Assistant Examiner(s): Haupt; Kristy A
• Application Number:
  US11/077,975
• Publication Number:
  US 20060202036A1
• Time in Patent Office: 1,607 Days
• Field of Search: 235/462.45, 235/462.1, 235/462.11, 235/462.25, 235/462.41, 235/462.07
• US Class Current: 235/462.45
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/1439 including a method step for retrieval of the optical code
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 25/70 SSIS architectures; Circuits associated therewith
• CPC Class Codes: H04N 25/745 Circuitry for generating timing or clock signals
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/7795 Circuitry for generating timing or clock signals
• CPC Class Codes: H04N 25/78 Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters

Abstract

The invention features an image reader and a corresponding method for capturing a sharp distortion free image of a target, such as a one or two-dimensional bar code. In one embodiment, the image reader comprises a two-dimensional CMOS based image sensor array, a timing module, an illumination module, and a control module. The time during which the target is illuminated is referred to as the illumination period. The capture of the image by the image sensor array is driven by the timing module that, in one embodiment, is able to simultaneously expose substantially all of the pixels in the array. The time during which the pixels are collectively activated to photo-convert incident light into charge defines the exposure period for the sensor array. In one embodiment, at least a portion of the exposure period occurs during the illumination period.

Claims

1. A complementary metal oxide semiconductor (CMOS) based image reader for collecting image data from a target, the CMOS based image reader comprising:

a CMOS based image sensor array, the CMOS based image sensor array comprising a plurality of rows of pixels, each of the pixels of the CMOS based image sensor array being an active pixel comprising a pixel amplifier, a photosensitive region and an opaque shielded data storage region;

a hand held housing encapsulating said image sensor array;

a timing module in electrical communication with the CMOS based image sensor array, the timing module configured to simultaneously expose a full frame of pixels of the CMOS based image sensor array during an exposure period;

an illumination module configured to illuminate the target during an illumination period, the illumination module in electrical communication with the timing module;

a control module in electrical communication with the timing module and the illumination module, the control module configured to cause at least a portion of the exposure period to occur during the illumination period;

wherein said CMOS based image sensor array is capable of being controlled so that exposure of pixels of a plurality of different rows of said CMOS based image sensor array is initiated simultaneously, and wherein said illumination period is less than a frame time of said CMOS based image reader; and

a bar code processing module capable of identifying representations of bar code symbols in collected image data.

2. The CMOS based image reader according to claim 1, wherein said illumination module for illuminating said target overdrives a light source of said illumination module.

3. The CMOS based image reader according to claim 1, wherein said illumination module comprises a light emitting diode.

4. The CMOS based image reader according to claim 1, wherein said exposure period is shorter than said illumination period.

5. The CMOS based image reader according to claim 1, wherein said illumination period is shorter than said exposure period.

6. The CMOS based image reader according to claim 1, wherein said illumination period commences before the start of said exposure period and said illumination period ends before the end of said exposure period.

7. The CMOS based image reader according to claim 1, wherein said illumination period commences before the start of said exposure period and said illumination period ends after the end of said exposure period.

8. The CMOS based image reader according to claim 1, wherein said illumination period commences after the start of said exposure period and said illumination period ends before the end of said exposure period.

9. The CMOS based image reader according to claim 1, wherein said illumination period commences after the start of said exposure period and said illumination period ends after the end of said exposure period.

10. The CMOS based image reader according to claim 1, wherein said illumination period commences before the start of said exposure period.

11. The CMOS based image reader according to claim 1, wherein said illumination period commences after the start of said exposure period.

12. The CMOS based image reader according to claim 1, wherein said illumination period ends before the end of said exposure period.

13. The CMOS based image reader according to claim 1, wherein said illumination period ends after the end of said exposure period.

14. The CMOS based image reader according to claim 1, wherein the exposure period is less than 3.7 milliseconds.

15. The CMOS based image reader according to claim 1, wherein the illumination period is less than 3.7 milliseconds.

16. The CMOS based image reader according to claim 1, wherein said illumination module during said illumination period is controlled utilizing a DC driving signal.

17. The CMOS based image reader according to claim 1, wherein said illumination module during said illumination period is controlled utilizing a strobed pulse.

18. A complementary metal oxide semiconductor (CMOS) based bar code reading device for collecting image data from a target, the CMOS based bar code reading device comprising:

an integrated circuit including at least a CMOS based image sensor array, the CMOS based image sensor array comprising a first plurality of pixels and a second plurality of pixels, the bar code reading device being programmable to selectively address and read out the first plurality of pixels of the CMOS based image sensor array independently of the second plurality of pixels of the CMOS based image sensor array, each of the pixels of the CMOS based image sensor array comprising a photosensitive region, an amplifier, and an opaque shielded data storage region;

a portable housing encapsulating said image sensor array;

a global electronic shutter control circuitry, the global electronic shutter control circuitry configured to generate an exposure control timing pulse that is capable of causing the simultaneous exposure of all or substantially all of an entire frame of pixels of the CMOS based image sensor array;

at least one light source configured to illuminate the target in response to an illumination control timing pulse, the at least one light source in electrical communication with the integrated circuit,

wherein at least a portion of the illumination control timing pulse overlaps with at least a portion of the exposure control timing pulse;

wherein said CMOS based image sensor array is capable of being controlled so that exposure of pixels of a plurality of different rows of said CMOS based image sensor array is initiated simultaneously, and wherein said illumination control timing pulse has a duration of less than a frame time of said CMOS based bar code reading device; and

a bar code processing module capable of identifying representations of bar code symbols in collected image data.

19. The CMOS based bar code reading device according to claim 18, wherein said CMOS based bar code reading device is configured so that for illumination of said target said CMOS based bar code reading device overdrives said at least one light source.

20. The CMOS based bar code reading device according to claim 19, wherein said at least one light source comprises a light emitting diode.

21. The CMOS based bar code reading device according to claim 18, wherein the exposure control timing pulse has a shorter duration than the illumination control timing pulse.

22. The CMOS based bar code reading device according to claim 18, wherein the illumination control timing pulse has a shorter duration than the exposure control timing pulse.

23. The CMOS based bar code reading device according to claim 18, wherein the illumination control timing pulse starts before the start of the exposure control timing pulse and the illumination control timing pulse ends before the end of the exposure control timing pulse.

24. The CMOS based bar code reading device according to claim 18, wherein the exposure control timing pulse has a duration of less than 3.7 milliseconds.

25. The CMOS based bar code reading device according to claim 18, wherein said illumination control timing pulse is a DC driving signal.

26. The CMOS based bar code reading device according to claim 18, wherein said illumination control timing pulse is a strobed pulse.

27. The CMOS based bar code reading device according to claim 18, wherein said illumination control timing pulse has a duration of less than 3.7 milliseconds.

28. The CMOS based bar code reading device according to claim 18, wherein said illumination period commences before the start of said exposure period and said illumination period ends after the end of said exposure period.

29. The CMOS based bar code reading device according to claim 18, wherein said illumination period commences after the start of said exposure period and said illumination period ends before the end of said exposure period.

30. The CMOS based bar code reading device according to claim 18, wherein said illumination period commences after the start of said exposure period and said illumination period ends after the end of said exposure period.

31. The CMOS based bar code reading device according to claim 18, wherein said illumination period commences before the start of said exposure period.

32. The CMOS based bar code reading device according to claim 18, wherein said illumination period commences after the start of said exposure period.

33. The CMOS based bar code reading device according to claim 18, wherein said illumination period ends before the end of said exposure period.

34. The CMOS based bar code reading device according to claim 18, wherein said illumination period ends after the end of said exposure period.

35. A bar code reading device for collecting and processing bar code data from a bar code symbol, the bar code reading device comprising:

a two-dimensional array of pixels for receiving light radiation reflected from the bar code symbol, the two-dimensional array of pixels comprising a first plurality of pixels and a second plurality of pixels, the bar code reading device being configured so that said bar code reading device can be controlled to selectively address and read out from said two-dimensional array image data from a first plurality of pixels of said array independently of a second plurality of pixels of said array, each of the pixels comprising a photosensitive region and an opaque shielded data storage region;

a hand held housing encapsulating said two-dimensional array of pixels;

an illumination module configured to illuminate a target during an illumination period, the illumination module in electrical communication with a timing module;

optics for directing light radiation reflected from the bar code symbol onto the two-dimensional array of pixels;

a global electronic shutter associated with the two-dimensional array of pixels, the global electronic shutter capable of simultaneously exposing all or substantially all of the pixels in the two-dimensional array, said global electronic shutter being capable of controlling said two-dimensional array so that exposure of pixels of a plurality of different rows of said two-dimensional array is initiated simultaneously, and wherein said illumination period is less than a frame time of said bar code reading device; and

a bar code processing module, the bar code processing module in electronic communication with the two-dimensional array of pixels, the bar code processing module capable of identifying representations of bar code symbols in collected image data.