Bar code reading device with global electronic shutter control

• US 20060202036A1
• Filed: 03/11/2005
• Published: 09/14/2006
• 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
• Granted Patent: US 7,568,628 B2
• Time in Patent Office: Days
• US Class Current: 235/462.70
• 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

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 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 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;

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; 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.

2. The bar code image reader according to claim 1, wherein the two-dimensional image sensor array is a complementary metal oxide (CMOS) image sensor.

3. The bar code image reader according to claim 1, wherein processing the image data to generate output data comprises automatically discriminating between a plurality of bar code types.

4. A complementary metal oxide semiconductor (CMOS) based image reader for collecting image data from a target, the CMOS based bar code reading device 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; and

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

5. 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 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 light sources 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; and

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

6. The CMOS based image reader according to claim 5, wherein illuminating the target comprises overdriving light sources in the illumination module.

7. The CMOS based image reader according to claim 6, wherein the light sources comprise light emitting diodes.

8. The CMOS based image reader according to claim 5, wherein the exposure control timing pulse has a shorter duration than the illumination control timing pulse.

9. The CMOS based image reader according to claim 5, wherein the illumination control timing pulse has a shorter duration than the exposure control timing pulse.

10. The CMOS based image reader according to claim 5, 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.

11. The CMOS based image reader according to claim 5, wherein the exposure control timing pulse has a duration of less than 3.7 milliseconds.

12. The CMOS based image reader according to claim 5, wherein the target includes a symbology.

13. The CMOS based image reader according to claim 12, wherein the symbology is a one-dimensional bar code.

14. The CMOS based image reader according to claim 12, wherein the symbology is a two-dimensional bar code.

15. The CMOS based image reader according to claim 14, wherein the two-dimensional bar code is a PDF417 bar code.

16. A portable bar code reading device for collecting image data from a bar code symbol, the bar code reading device comprising:

a hand held housing;

an integrated circuit including at least a two-dimensional image sensor array, the two-dimensional image sensor array including a plurality of active pixels, and being disposed within said hand held housing each active pixel including at least a shielded data storage area, the two-dimensional image sensor array capable of employing a transfer function to convert an incident light intensity into an output voltage, the transfer function having a first region with a first slope and a second region with a second slope, the two-dimensional image sensor array capable of employing the second region of the transfer function when the incident light intensity is above a specified level and the two-dimensional image sensor array capable of employing the first region of the transfer function when the incident intensity is below a specified level;

a manual trigger, wherein said bar code reading device is configured so that depressing said manual trigger generates a trigger signal and drives said bar code reading device from an idle state to an active reading state; and

an exposure timing control circuitry, the exposure timing control circuitry configured to generate an exposure control timing pulse that is capable of simultaneously exposing all or substantially all of the pixels in the image sensor array to photoconvert incident radiation, wherein said portable bar code reading device is configured so that subsequent to depression of said manual trigger, said bar code reading device collects image data and transfers said image data to a bar code decode module.

17. The bar code image reader according to claim 16, wherein the exposure control timing pulse has a duration of less than 3.7 milliseconds.

18. The bar code image reader according to claim 16, wherein a dynamic range of the two-dimensional image array sensor is greater than 65 decibels.

19. The bar code image reader according to claim 16, wherein the bar code image reader collects image data from a two-dimensional bar code.

20. The bar code image reader according to claim 19, wherein the two-dimensional bar code is a PDF417 bar code.