Image reader comprising CMOS based image sensor array

• US 10,171,767 B2
• Filed: 01/09/2017
• Issued: 01/01/2019
• 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: Wang, Ynjiun P., Havens, William H.
• Primary Examiner(s): Haupt, Kristy A
• Application Number:
  US15/401,779
• Publication Number:
  US 20170353684A1
• Time in Patent Office: 722 Days
• Field of Search: None
• 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 method for capturing and decoding at least a two dimensional bar code in image data captured by an image reader, the image reader comprising an image sensor array comprising plurality of pixels in a two-dimensional array, and the image reader further comprising at least one illumination light source, the method comprising:

exposing all or substantially all of the pixels in the image sensor array in a global shutter mode, wherein exposing the all or substantially all of the pixels in the global shutter mode comprises exposing the all or substantially all of the pixels in response to an exposure control timing pulse; and

illuminating at least a portion of the bar code in response to an illumination control timing pulse;

wherein the exposure control timing pulse and the illumination control timing pulse are interdependent.

2. The method of claim 1, further comprising selecting a decoding algorithm for decoding the representation of the bar code from a plurality of decoding algorithms each configured to decode a different one dimensional bar code or a two dimensional bar code.

3. The method of claim 1, further comprising projecting a two-dimensional observable illumination pattern over the target with the at least one illumination light source.

4. The method of claim 1, further comprising operating the at least one illumination light source at a substantially peak power level during at least a portion of the exposure control timing pulse.

5. The method of claim 1, further comprising operating the at least one illumination light source at a substantially peak power level during at least a portion of the exposure control timing pulse and deactivating the at least one illumination light source during another portion of the exposure control timing pulse.

6. The method of claim 1, further comprising determining whether the image data comprises a one dimensional bar code or a two dimensional bar code.

7. The method of claim 1, further comprising decoding two or more of a one dimensional universal product code bar code, a two dimensional PDF417 bar code or a bar code having abutting bar code symbols.

8. The method of claim 1, wherein the at least one illumination light source is configured to be substantially bright and the exposure control timing pulse is configured to be substantially short so as to enable the image data to be substantially non-distorted.

9. The method of claim 1, further comprising:

reading out a set of digital values corresponding to incident light on a plurality of pixels of the image sensor array simultaneously exposed to capture the image data, a frame of image data comprises a plurality of pixel values, wherein the read out is controlled by a read out timing control pulse.

10. The method of claim 9, wherein a read out control timing pulse begins at the conclusion of the illumination control timing pulse.

11. The method of claim 9, wherein a read out control timing pulse begins at the conclusion of the exposure control timing pulse.

12. The method of claim 1, wherein the image reader further comprises:

a lens driver module, wherein the lens sensor driver module has a plurality of discrete settings, each discrete setting being configured to cause the image data to be collected by the image sensor for objects located at a particular distance from the image reader.

13. The method of claim 1, further comprising:

reading the image data from one or more exposed rows;

analyzing the image data with a focusing algorithm operable to determine an auto-focus setting; and

moving a lens according to the auto-focus setting.

14. The method of claim 1, wherein the image reader comprises one or more of a magnetic stripe reader, a biometric reader, a printer, a radio-frequency identification tag reader, a radio-frequency payment reader, or a smart card reader.

15. The method of claim 1, further comprising performing feature extraction such that a quiet zone is identifiable in the image data.

16. The method of claim 1, further comprising performing feature extraction such that a finder pattern is identifiable in the image data.

17. The method of claim 1, wherein the illumination control timing pulse occurs in response to the exposure control timing pulse.

18. The method of claim 1, wherein the exposure control timing pulse occurs in response to the illumination control timing pulse.

19. The method of claim 1, further comprising operating the at least one illumination light source at a peak power level during at least a portion of the exposure control timing pulse in accordance with a power budget.

20. The method of claim 1, wherein the image sensor array comprises an infrared filter.

21. The method of claim 1, wherein an exposure time is the time between the pixels being reset and a value of the pixels being read out, and wherein the illumination control timing pulse is shorter than the exposure time.

22. A method comprising:

exposing all or substantially all of the pixels in an image sensor array in a global shutter mode in response to an exposure control timing pulse to collect image data;

decoding representations of at least a two dimensional bar code in a grey level image captured by an image reader that is configured to operate an image sensor array operable in a global shutter mode to capture a substantially distortion free image;

wherein the image reader further comprises the image sensor array comprising a plurality of pixels in a two-dimensional array;

illuminating at least a portion of the bar code with at least one illumination light source in response to an illumination control timing pulse, wherein the exposure control timing pulse and the illumination control timing pulse are interdependent; and

searching the captured grey level image for one or more markers, wherein in an instance in which at least one marker of the one or more markers is detected, the method further comprises decoding the captured grey level image in accordance with a decoding algorithm associated with the at least one marker.

23. The method of claim 22, further comprising selecting a decoding algorithm for decoding the representation of the bar code from a plurality of decoding algorithms each configured to decode a different one dimensional bar code or a two dimensional bar code.

24. The method of claim 22, further comprising projecting a two-dimensional observable illumination pattern over the target with the at least one illumination light source.

25. The method of claim 22, further comprising operating the at least one illumination light source at a substantially peak power level during at least a portion of the exposure control timing pulse.

26. The method of claim 22, further comprising operating the at least one illumination light source at a substantially peak power level during at least a portion of the exposure control timing pulse and deactivating the at least one illumination light source during another portion of the exposure control timing pulse.

27. The method of claim 22, further comprising determining whether the image data comprises a one dimensional bar code or a two dimensional bar code.

28. The method of claim 22, further comprising decoding two or more of a one dimensional universal product code bar code, a two dimensional PDF417 bar code or a bar code having abutting bar code symbols.

29. The method of claim 22, wherein the at least one illumination light source is configured to be substantially bright and the exposure control timing pulse is configured to be substantially short so as to enable the image data to be substantially non-distorted.

30. The method of claim 22, further comprising:

reading out a set of digital values corresponding to incident light on a plurality of pixels of the image sensor array simultaneously exposed to capture the image data, a frame of image data comprises a plurality of pixel values, wherein the read out is controlled by a read out timing control pulse.

31. The method of claim 30, wherein a read out control timing pulse begins at the conclusion of the illumination control timing pulse.

32. The method of claim 30, wherein a read out control timing pulse begins at the conclusion of the exposure control timing pulse.

33. The method of claim 22, wherein the image reader further comprises:

a lens driver module, wherein the lens sensor driver module has a plurality of discrete settings, each discrete setting being configured to cause the image data to be collected by the image sensor for objects located at a particular distance from the image reader.

34. The method of claim 22, further comprising:

reading the image data from one or more exposed rows;

analyzing the image data with a focusing algorithm operable to determine an auto-focus setting; and

moving a lens according to the auto-focus setting.

35. The method of claim 22, wherein the image reader comprises one or more of a magnetic stripe reader, a biometric reader, a printer, a radio-frequency identification tag reader, a radio-frequency payment reader, or a smart card reader.

36. The method of claim 22, further comprising performing feature extraction such that a quiet zone is identifiable in the image data.

37. The method of claim 22, further comprising performing feature extraction such that a finder pattern is identifiable in the image data.

38. The method of claim 22, wherein the illumination control timing pulse occurs in response to the exposure control timing pulse.

39. The method of claim 22, wherein the exposure control timing pulse occurs in response to the illumination control timing pulse.

40. The method of claim 22, further comprising operating the at least one illumination light source at a peak power level during at least a portion of the exposure control timing pulse in accordance with a power budget.

41. The method of claim 22, wherein the image sensor array comprises an infrared filter.

42. The method of claim 22, wherein an exposure time is the time between the pixels being reset and a value of the pixels being read out, and wherein the illumination control timing pulse is shorter than the exposure time.

43. A method for capturing and decoding at least a two dimensional bar code in image data captured by an image reader, the image reader comprising an image sensor array comprising plurality of pixels in a two-dimensional array, and the image reader further comprising at least one illumination light source, the method comprising:

transmitting an exposure control timing pulse to cause exposure of all or substantially all of the pixels in the image sensor array in a global shutter mode in response to the exposure control timing pulse; and

transmitting an illumination control timing pulse to cause illumination of at least a portion of the bar code in response to an illumination control timing pulse;

wherein the exposure control timing pulse and the illumination control timing pulse are interdependent.

44. The method of claim 43, wherein an exposure time is the time between the pixels being reset and a value of the pixels being read out, and wherein the illumination control timing pulse is shorter than the exposure time.