Time division exposure of a data reader

• US 9,141,842 B2
• Filed: 02/14/2013
• Issued: 09/22/2015
• Est. Priority Date: 02/15/2012
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Gao, WenLiang
• Primary Examiner(s): LE, THIEN MINH
• Application Number:
  US13/767,652
• Publication Number:
  US 20130206839A1
• Time in Patent Office: 950 Days
• Field of Search: 23547201-47203, 23546201-46245
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10861 sensing of data fields affixed to objects or articles, e.g. coded labels postal sorting B07C3/14, conveying articles B65G47/48
• CPC Class Codes: G06K 7/1096 the scanner having more than one scanning window, e.g. two substantially orthogonally placed scanning windows for integration into a check-out counter of a super-market

Abstract

Disclosed systems and methods generate a sequence of images using a data reader having an imager exposed to multiple fields of view that are alternately illuminated to coincide with exposure periods forming an image capture rate. In one configuration, a first illumination source illuminates a first field of view of the data reader with a first series of illumination pulses at a first pulse repetition rate. The imager captures in an alternating manner a first set of images of the first field of view and a second set of images of a second field of view. The first pulse repetition rate and the image capture rate are set such that the imager captures the first set of images at approximately the same time as the first illumination source illuminates the first field of view with an illumination pulse.

Claims

1. A method for generating image data using a data reader having an imager with multiple fields of view, the method comprising:

directing a first field of view of the imager along a first path;

directing a second field of view of the imager along a second path;

illuminating, via a first illumination source, the first field of view of the data reader with a first series of illumination pulses at a first pulse repetition rate;

capturing at the imager a sequence of images at an image capture rate and in an alternating manner with a first set of images of the first field of view and a second set of images of the second field of view and wherein the first pulse repetition rate and the image capture rate are set such that the imager captures the first set of images during the first illumination source illuminating the first field of view with an illumination pulse; and

in response to receiving a request to capture images of one of the first and second illuminated fields of view, causing the imager to capture images of the one of the first and second illuminated fields of view without capturing images of the other one of the first and second illuminated fields of view.

2. The method of claim 1, further comprising:

illuminating, via a second illumination source, the second field of view of the data reader with a second series of illumination pulses at a second pulse repetition rate, wherein the second pulse repetition rate and the image capture rate are set such that the imager captures the second set of images during the second illumination source illuminating the second field of view with an illumination pulse.

3. The method of claim 2, wherein the first pulse repetition rate and the second pulse repetition rate are set to approximately 90 hertz and the image capture rate is set to approximately 60 frames per second.

4. The method of claim 2, wherein the first pulse repetition rate and the second pulse repetition rate are set to approximately 1.5 times the image capture rate.

5. The method of claim 2, wherein the first pulse repetition rate and the second pulse repetition rate are set to approximately 60 hertz and the image capture rate is set to approximately 60 frames per second, the method further comprising:

delaying every other illumination pulse in the first series of illumination pulses such that the imager captures the first set of images at approximately the same time as the first illumination source illuminates the first field of view with an illumination pulse and the first illumination source does not illuminate the first field of view with an illumination pulse when the imager captures the second set of images; and

delaying every other illumination pulse in the second series of illumination pulses such that the imager captures the second set of images at approximately the same time as the second illumination source illuminates the second field of view with an illumination pulse and the second illumination source does not illuminate the second field of view with an illumination pulse when the imager captures the first set of images.

6. The method of claim 2, wherein the first pulse repetition rate and the second pulse repetition rate are set approximately equal to the image capture rate, the method further comprising:

delaying every other illumination pulse in the first series of illumination pulses such that the imager captures the first set of images at approximately the same time as the first illumination source illuminates the first field of view with an illumination pulse and the first illumination source does not illuminate the first field of view with an illumination pulse when the imager captures the second set of images; and

delaying every other illumination pulse in the second series of illumination pulses such that the imager captures the second set of images at approximately the same time as the second illumination source illuminates the second field of view with an illumination pulse and the second illumination source does not illuminate the second field of view with an illumination pulse when the imager captures the first set of images.

7. The method of claim 2, wherein a wavelength of the first and second illumination sources are approximately equal to each other.

8. The method of claim 1, wherein the imager is configured to capture the first and second set of images over respective first and second exposure durations and the second exposure duration is greater than the first exposure duration.

9. The method of claim 1, further comprising:

processing, via a processor, the sequence of images to detect decodable data corresponding to an optical code.

10. The method of claim 1, wherein light from the second field of view is not prevented from reaching the imager while the imager captures the first set of images.

11. The method of claim 1, wherein the imager captures in the alternating manner the first and second sets of images independent of any mechanical moving parts.

12. The method of claim 1, wherein the imager includes a set of pixel imaging elements and wherein the first and second fields of view are directed toward the imager such that the first and second fields of view are focused onto substantially all of the set of pixel imaging elements of the imager.

13. The method of claim 1, wherein the first and second fields of view are directed toward a common portion of the imager.

14. The method of claim 1, wherein the first and second fields of view are not directed toward different portions of the imager.

15. The method of claim 1, wherein the first set of images comprises a single image and the second set of images comprises two or more images.

16. The method of claim 1, further comprising:

in response to receiving a request to adjust the first pulse repetition rate from a first value to a second value that is different from the first value, adjusting the first pulse repetition rate to the second value.

17. The method of claim 1, further comprising:

in response to receiving a request to adjust the image capture rate from a first value to a second value that is different from the first value, adjusting the image capture rate to the second value.

18. The method of claim 1, wherein at least a portion of the first and second fields of view do not overlap.

19. The method of claim 1, wherein the first and second fields of view do not overlap.

20. A method for generating image data using a data reader having an imager with multiple fields of view, the method comprising:

directing a first field of view of the imager along a first path;

directing a second field of view of the imager along a second path;

illuminating, via a first illumination source, the first field of view of the data reader with a first series of illumination pulses at a first pulse repetition rate;

capturing at the imager a sequence of images at an image capture rate and in an alternating manner with a first set of images of the first field of view and a second set of images of the second field of view and wherein the first pulse repetition rate and the image capture rate are set such that the imager captures the first set of images during the first illumination source illuminating the first field of view with an illumination pulse, wherein one of the first or second fields of view corresponds to a checker side of the data reader and the other one of the first or second fields of view corresponds to a customer side of the data reader.

21. A data reader, comprising:

a first illumination source configured to illuminate a first field of view of the data reader with a first series of illumination pulses at a first pulse repetition rate;

an imager including a set of pixel imaging elements arranged in a two-dimensional imaging plane;

a lens in optical association with the imager and configured to focus one or more fields of view onto substantially all of the pixel imaging elements of the imager;

a beam splitter in optical association with the lens and the imager, wherein the beam splitter is configured to direct light from the first field of view of the data reader along a first path to the lens and the imager and to direct light from a second field of view of the data reader along a second path to the lens and the imager; and

a controller configured to be in operative association with the first illumination source and the imager, the controller configured to cause the imager to capture a sequence of images at an image capture rate, wherein the imager captures in an alternating manner a first set of images of the first field of view and a second set of images of the second field of view and wherein the first pulse repetition rate and the image capture rate are set such that the imager captures the first set of images at approximately the same time as the first illumination source illuminates the first field of view with an illumination pulse.

22. The data reader of claim 21, further comprising:

a second illumination source configured to illuminate the second field of view of the data reader with a second series of illumination pulses at a second pulse repetition rate, wherein the second pulse repetition rate and the image capture rate are set such that the imager captures the second set of images at approximately the same time as the second illumination source illuminates the second field of view with an illumination pulse.

23. The data reader of claim 21, further comprising:

one or more fixed mirrors in optical association with the beam splitter, the lens, and the imager, wherein the one or more fixed mirrors are configured to redirect the second field of view toward the beam splitter.

24. The data reader of claim 21, wherein at least a portion of the first and second fields of view do not overlap.

25. The data reader of claim 21, wherein the first and second fields of view do not overlap.