Systems and methods for forming a composite image of multiple portions of an object from multiple perspectives

• US 8,746,569 B2
• Filed: 01/15/2013
• Issued: 06/10/2014
• Est. Priority Date: 02/12/2008
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Olmstead, Bryan L.
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): LY, TOAN C
• Application Number:
  US13/742,273
• Publication Number:
  US 20130126617A1
• Time in Patent Office: 511 Days
• Field of Search: 235/462.41
• US Class Current: 235/462.41
• CPC Class Codes: G06K 7/10 by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
• CPC Class Codes: G06K 7/10732 Light sources

Abstract

Various improved imager-based optical code readers and associated methods are disclosed herein. According to one embodiment, an imager-based method reads an optical code (which may be, for example, a linear optical code such as a bar code) on an object in a viewing volume. The method comprises dividing an image plane into a plurality of strip-shaped sections, viewing the object in the viewing volume from a plurality of perspectives, forming a plurality of strip-shaped images corresponding to the plurality of perspectives, respectively, thereby creating a composite image containing data from a plurality of perspectives, and processing at least a portion of the composite image so as to ascertain the information encoded in the optical code on the object in the viewing volume. Certain embodiments can mimic the performance of a laser-based scanner without a laser or moving parts but instead utilizing an electronic imaging device such as an imager.

Claims

1. An imager-based method for reading an optical code on an object in a viewing volume, the method comprising:

dividing an image plane into a plurality of strip-shaped sections;

viewing a side of the object in the viewing volume from a plurality of crossing perspectives, the crossing perspectives forming pseudo scan lines with a plurality of angular crossings on the side of the object in the viewing volume;

forming a plurality of strip-shaped images corresponding to the plurality of crossing perspectives, respectively, wherein the strip-shaped images are in the strip-shaped sections of the image plane, thereby creating a composite image containing data from the plurality of crossing perspectives; and

processing at least a portion of the composite image so as to ascertain the information encoded in the optical code on the object in the viewing volume.

2. A method according to claim 1, wherein the optical code is a linear optical code, and the method further comprises:

processing a virtual scan line across at least one of the strip-shaped sections to decode the linear optical code.

3. A method according to claim 1, wherein the composite image comprises a rectangular array of pixels arranged as horizontal rows, wherein the imager is a row-wise rolling-reset imager, and wherein the strip-shaped sections are sets of N contiguous rows, wherein N is a positive integer.

4. A method according to claim 3, wherein the imager is a rolling-reset imager characterized by a frame rate, and wherein the step of forming a plurality of strip-shaped images corresponding to the plurality of perspectives, respectively, comprises:

sequentially forming the strip-shaped images on successive sets of N contiguous rows; and

repeating the step of forming a plurality of strip-shaped images corresponding to the plurality of perspectives, respectively, a whole number of times per frame of the rolling-reset imager.

5. A method according to claim 1, further comprising:

illuminating the object in the viewing volume from said plurality of crossing perspectives in respective synchronicity with forming said plurality of strip-shaped images.

6. A method according to claim 1 wherein the crossing perspectives comprise at least a first group of a first plurality of parallel perspectives and a second group of a second plurality of parallel perspectives, the first group being non-parallel to the second group with at least some perspectives of the first group angularly crossing at least some perspectives of the second group.

7. A method according to claim 1 wherein the crossing perspectives form a plurality of angular crossings on the side of the object in the viewing volume.

8. A method for generating useful image data for an optical code on an object in a viewing volume using an imager and one or more fixed mirrors, the method comprising:

projecting onto a first portion of the imager via a first set of fixed mirrors a first partial view of a side of the object from a first perspective into the viewing volume;

projecting onto a second portion of the imager via a second set of fixed mirrors a second partial view of the side of the object from a second perspective into the viewing volume, wherein the second perspective is different from the first perspective in at least one of viewing position and viewing angle, and wherein the second portion of the imager is different from the first portion of the imager;

projecting onto a third portion of the imager via a third set of fixed mirrors a third partial view of the side of the object from a third perspective into the viewing volume, wherein the third perspective is different from both the first perspective and the second perspective in at least viewing angle, the third perspective angularly crossing both the first perspective and the second perspective on the side of the object in the viewing volume, and wherein the third portion of the imager is different from both the first portion and the second portion of the imager, wherein the first, second and third portions of the imager are substantially aligned in a common direction across the imager thereby creating a composite image from the first, second and third partial views of the side of the object; and

processing at least a portion of the composite image so as to ascertain information encoded in the optical code on the object in the viewing volume.

9. A method according to claim 8, wherein the optical code is a one-dimensional optical code.

10. A method according to claim 9, further comprising:

attempting to decode the one-dimensional optical code along a virtual scan line traversing the first portion of the imager;

attempting to decode the one-dimensional optical code along a virtual scan line traversing the second portion of the imager; and

attempting to decode the one-dimensional optical code along a virtual scan line traversing the third portion of the imager.

11. A method according to claim 8, wherein each projecting step comprises reflecting the partial image off at least two mirrors and onto the imager.

12. A method according to claim 8, further comprising:

focusing each partial image onto the imager.

13. A method according to claim 8, further comprising:

illuminating the object in the viewing volume.

14. A method according to claim 13, wherein illuminating the object in the viewing volume comprises:

illuminating the area where the first portion of the object is at approximately the same time when the first portion of the imager is exposed for imaging;

illuminating the area where the second portion of the object is at approximately the same time when the second portion of the imager is exposed for imaging; and

illuminating the area where the third portion of the object is at approximately the same time when the third portion of the imager is exposed for imaging.

15. A method according to claim 14, wherein illuminating the area where the first portion of the object is comprises directing light at the object from the first perspective, illuminating the area where the second portion of the object is comprises directing light at the object from the second perspective, and illuminating the area where the third portion of the object is comprises directing light at the object from the third perspective.

16. A method according to claim 8, further comprising:

resetting the imager.

17. A method according to claim 8 wherein the first, second and third perspectives form a plurality of angular crossings on the side of the object in the viewing volume.

18. A system for generating useful image data for an optical code on an object in a viewing volume using an imager and one or more fixed mirrors, the system comprising:

means for projecting onto a first portion of the imager via a first set of fixed mirrors a first partial view of a side of the object from a first perspective into the viewing volume;

means for projecting onto a second portion of the imager via a second set of fixed mirrors a second partial view of the side of the object from a second perspective into the viewing volume, wherein the second perspective is different from the first perspective in at least one of viewing position and viewing angle, and wherein the second portion of the imager is different from the first portion of the imager;

means for projecting onto a third portion of the imager via a third set of fixed mirrors a third partial view of the side of the object from a third perspective into the viewing volume, wherein the third perspective is different from both the first perspective and the second perspective in at least and viewing angle, the third perspective angularly crossing both the first perspective and the second perspective on the side of the object in the viewing volume, and wherein the third portion of the imager is different from both the first portion and the second portion of the imager, wherein the first, second and third portions of the imager are substantially aligned in a common direction across the imager thereby creating a composite image from the first, second and third partial views of the side of the object; and

means for processing at least a portion of the composite image so as to ascertain information encoded in the optical code on the object in the viewing volume.

19. A system according to claim 18 wherein the first, second and third perspectives form a plurality of angular crossings on the side of the object in the viewing volume.

20. A imager-based system for reading an optical code on an object in a viewing volume, the system comprising:

means for viewing a side of the object in the viewing volume from a plurality of angular crossing perspectives;

means for forming a plurality of strip-shaped images corresponding to the plurality of angular crossing perspectives on the side of the object in the viewing volume, respectively;

means for creating a composite image by dividing an image into a plurality of strip-shaped sections, wherein the strip-shaped images are in the strip-shaped sections; and

means for ascertaining information encoded in the optical code on the object in the viewing volume.

21. A method according to claim 20 wherein the angular crossing perspectives comprise at least a first group of a first plurality of parallel perspectives and a second group of a second plurality of parallel perspectives, the first group being non-parallel to the second group with at least some perspectives of the first group angularly crossing at least some perspectives of the second group.

22. A method according to claim 20 wherein the angular crossing perspectives form a plurality of angular crossings on the side of the object in the viewing volume.