Selecting illumination characteristics that will be most suitable for reading a barcode

• US 8,820,643 B1
• Filed: 07/19/2013
• Issued: 09/02/2014
• Est. Priority Date: 07/19/2013
• Status: Expired due to Fees

• Current Assignee: The Code Corporation (Brady Corporation)
• Original Assignee: The Code Corporation (Brady Corporation)
• Inventors: Lei, Ming, Hoobler, Ryan
• Primary Examiner(s): LEE, SEUNG H
• Application Number:
  US13/946,862
• Time in Patent Office: 410 Days
• Field of Search: 235/454, 235/462.2, 235/462.22, 235/462.25, 235/462.41, 235/462.42
• US Class Current: 235/462.06
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/1465 using several successive scans of the optical code

Abstract

A barcode reader may be configured to capture at least one test image of at least a portion of a barcode. The at least one test image may include a plurality of window images. Each window image may be smaller than a full photo sensor array image. Illumination for each window image may be provided by a distinct one of the plurality of illumination systems. The barcode reader may also be configured to determine a selected illumination system. The selected illumination system may be the illumination system that yielded a window image having highest quality among the plurality of window images. The barcode reader may also be configured to cause the photo sensor array to capture a subsequent image using the selected illumination system.

Claims

1. A barcode reader, comprising:

a photo sensor array;

a plurality of illumination systems having different illumination characteristics; and

circuitry that is configured to;

cause the photo sensor array to capture at least one test image of at least a portion of a barcode, wherein the at least one test image comprises a plurality of window images, each window image being smaller than a full photo sensor array image, wherein illumination for each window image is provided by a distinct configuration of the plurality of illumination systems;

determine a selected illumination system configuration, the selected illumination system configuration being a configuration of the plurality of illumination systems that yielded a window image having highest quality among the plurality of window images; and

cause the photo sensor array to capture a subsequent image using the selected illumination system configuration.

2. The barcode reader of claim 1, wherein determining the selected illumination system configuration comprises:

determining which window image of the plurality of window images has highest contrast between light and dark cells of the barcode; and

determining which configuration of the plurality of illumination systems was activated when the window image having the highest contrast was captured.

3. The barcode reader of claim 1, wherein determining the selected illumination system configuration comprises:

determining which window image of the plurality of window images has a most favorable score based on features or patterns of the barcode; and

determining which configuration of the plurality of illumination systems was activated when the window image having the most favorable score was captured.

4. The barcode reader of claim 1, wherein:

the circuitry is configured to cause the photo sensor array to capture a single test image using a rolling shutter mode of operation; and

each window image corresponds to a distinct band within the single test image.

5. The barcode reader of claim 4, wherein the circuitry is configured to cycle through a plurality of configurations of the plurality of illumination systems while the single test image is being captured, so that each illumination system configuration is activated for a distinct time period while the single test image is being captured and is not otherwise activated while the single test image is being captured.

6. The barcode reader of claim 1, wherein:

the circuitry is configured to cause the photo sensor array to capture a plurality of test images, each test image being smaller than a full photo sensor array image; and

each window image corresponds to a different one of the plurality of test images.

7. The barcode reader of claim 6, wherein the photo sensor array captures the plurality of test images using a rolling shutter mode of operation.

8. The barcode reader of claim 7, wherein the plurality of test images correspond to different sections of the photo sensor array.

9. The barcode reader of claim 7, wherein the plurality of test images correspond to the same section of the photo sensor array.

10. The barcode reader of claim 6, wherein the photo sensor array captures the plurality of test images using a global shutter mode of operation.

11. The barcode reader of claim 10, wherein the plurality of test images correspond to different sections of the photo sensor array.

12. The barcode reader of claim 10, wherein the plurality of test images correspond to the same section of the photo sensor array.

13. The barcode reader of claim 1, wherein:

the at least one test image comprises only a portion of the barcode; and

the subsequent image comprises the entire barcode.

14. The barcode reader of claim 1, wherein the different illumination characteristics are selected from the group consisting of angle of illumination with respect to an optical axis, intensity of illumination, wavelength of illumination, and diffusion characteristics of the illumination.

15. The barcode reader of claim 1, wherein the width of the at least one test image and the width of the plurality of window images are equal to the width of the photo sensor array.

16. The barcode reader of claim 1, wherein the width of the at least one test image and the width of the plurality of window images are less than the width of the photo sensor array.

17. The barcode reader of claim 1, wherein the subsequent image comprises pixels corresponding to substantially all photo sensors in the photo sensor array.

18. The barcode reader of claim 1, wherein:

the at least one test image comprises pixels corresponding to a first subset of photo sensors in the photo sensor array;

the subsequent image comprises pixels corresponding to a second subset of the photo sensors in the photo sensor array; and

the second subset is greater than the first subset.

19. A barcode reader, comprising:

a photo sensor array;

at least one illumination system that is configured to provide illumination having different illumination characteristics; and

illumination selection circuitry that is configured to;

cause the photo sensor array to capture, using one or more test images, a plurality of window images of at least a portion of a barcode, the plurality of window images including a first window image and a second window image, each window image being smaller than a full photo sensor array image, wherein illumination having a first set of illumination characteristics is used for capturing the first window image, and wherein illumination having a second set of illumination characteristics different than the first set of illumination characteristics is used for capturing the second window image;

determine a selected set of illumination characteristics, the selected set of illumination characteristics being a set of illumination characteristics that yielded a window image having highest quality among the plurality of window images; and

cause the photo sensor array to capture a subsequent image using the selected set of illumination characteristics.

20. The barcode reader of claim 19, wherein determining the selected set of illumination characteristics comprises:

determining which window image of the plurality of window images has highest contrast between light and dark cells of the barcode; and

determining which illumination characteristic was utilized when the window image having the highest contrast was captured.

21. The barcode reader of claim 19, wherein determining the selected set of illumination characteristics comprises:

determining which window image of the plurality of window images has a most favorable score based on features or patterns of the barcode; and

determining which illumination characteristic was utilized when the window image having the most favorable score was captured.

22. The barcode reader of claim 19, wherein:

the circuitry is configured to cause the photo sensor array to capture a single test image using a rolling shutter mode of operation; and

each window image corresponds to a distinct band within the single test image.

23. The barcode reader of claim 22, wherein the circuitry is configured to cycle through a plurality of sets of illumination characteristics while the single test image is being captured, so that each set of illumination characteristics is utilized for a distinct time period while the single test image is being captured and is not otherwise utilized while the single test image is being captured.

24. The barcode reader of claim 19, wherein:

the circuitry is configured to cause the photo sensor array to capture a plurality of test images, each test image being smaller than a full photo sensor array image; and

each window image corresponds to a different one of the plurality of test images.

25. The barcode reader of claim 24, wherein the photo sensor array captures the plurality of test images using a rolling shutter mode of operation.

26. The barcode reader of claim 25, wherein the plurality of test images correspond to different sections of the photo sensor array.

27. The barcode reader of claim 25, wherein the plurality of test images correspond to the same section of the photo sensor array.

28. The barcode reader of claim 24, wherein the photo sensor array captures the plurality of test images using a global shutter mode of operation.

29. The barcode reader of claim 28, wherein the plurality of test images correspond to different sections of the photo sensor array.

30. The barcode reader of claim 28, wherein the plurality of test images correspond to the same section of the photo sensor array.

31. The barcode reader of claim 19, wherein:

the one or more test images comprise only a portion of the barcode; and

the subsequent image comprises the entire barcode.

32. The barcode reader of claim 19, wherein the different illumination characteristics are selected from the group consisting of from angle of illumination with respect to an optical axis, intensity of illumination, wavelength of illumination, and diffusion characteristics of the illumination.