Method and apparatus for scanning with controlled spherical aberration

• US 9,158,953 B2
• Filed: 02/14/2014
• Issued: 10/13/2015
• Est. Priority Date: 02/14/2014
• Status: Active Grant

• Current Assignee: Intermec Technologies Corporation (Honeywell International Inc.)
• Original Assignee: Intermec Technologies Corporation (Honeywell International Inc.)
• Inventors: Gillet, Alain, Bessettes, Vincent
• Primary Examiner(s): LEE, SEUNG H
• Application Number:
  US14/181,550
• Publication Number:
  US 20150235068A1
• Time in Patent Office: 606 Days
• Field of Search: 235/436, 235/454, 235/462.15, 235/462.1, 235/462.11
• US Class Current: 1/1
• CPC Class Codes: G02B 27/0075 with means for altering, e.g. increasing, the depth of field or depth of focus
• CPC Class Codes: G06K 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/1413 1D bar codes
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G06K 7/1439 including a method step for retrieval of the optical code
• CPC Class Codes: G06K 7/146 the method including quality enhancement steps
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device

Abstract

A reader obtains image data corresponding to an image of optically encoded information that is received via a lens unit that causes controlled spherical aberration blurring that is precisely known. The reader may perform deconvolution processing on the image data to render it decodable. The deconvolution processing may implement a Weiner filter that uses data corresponding to a near-field point spread function of the lens unit. The depth of field of the reader is greater than that of conventional reader in all lighting conditions.

Claims

1. A method of decoding optically encoded information performed by an image processing system, the method comprising:

obtaining first image data corresponding to an image of optically encoded information received via a lens unit that causes controlled spherical aberration;

performing first processing on the first image data;

responsive to the first processing on the first image data not producing data corresponding to the optically encoded information, obtaining second image data by performing second processing on the first image data and performing the first processing on the second image data; and

responsive to the first processing on the second image data not producing the data corresponding to the optically encoded information, obtaining third image data by performing third processing on the first image data and performing the first processing on the third image data;

wherein the lens unit causes predetermined spherical aberration blurring in the image of the optically encoded information.

2. The method of claim 1 wherein the second processing includes deconvolution processing.

3. The method of claim 1 wherein the second processing includes Weiner filter deconvolution processing.

4. The method of claim 3 wherein the Weiner filter deconvolution processing is performed using data corresponding to a point spread function of the lens unit.

5. The method of claim 3 wherein the Weiner filter deconvolution processing is performed using data corresponding to a near-field point spread function of the lens unit.

6. The method of claim 3 wherein the Weiner filter deconvolution processing is performed using a one-dimensional deconvolution kernel.

7. The method of claim 1 wherein the third processing includes deconvolution processing.

8. The method of claim 1 wherein the third processing includes Weiner filter deconvolution processing.

9. The method of claim 8 wherein the Weiner filter deconvolution processing is performed using data corresponding to a point spread function of the lens unit.

10. The method of claim 8 wherein the Weiner filter deconvolution processing is performed using data corresponding to a near-field point spread function of the lens unit.

11. The method of claim 8 wherein the Weiner filter deconvolution processing is performed using two one-dimensional deconvolution kernels.

12. The method of claim 8 wherein the Weiner filter deconvolution processing is performed using a first deconvolution kernel matrix and a second deconvolution kernel matrix that is orthogonal to the first deconvolution kernel matrix.

13. The method of claim 12 wherein the second deconvolution kernel matrix corresponds to the first deconvolution kernel matrix rotated by ninety degrees.

14. The method of claim 1 wherein the optically encoded information includes a one-dimensional barcode symbol.

15. The method of claim 1 wherein the optically encoded information includes a two-dimensional machine-readable symbol.

16. The method of claim 1 wherein the lens unit causes more near-field spherical aberration blurring than far-field spherical aberration blurring.

17. The method of claim 1 wherein the lens unit produces spherical aberration blurring such that offsetting fifth order effects are added to third order solutions to a spherical aberration equation.

18. The method of claim 1, further comprising:

outputting the data corresponding to the optically encoded information.

19. An image processing system, the method comprising:

one or more processors; and

one or more processor-readable storage media storing processor-executable instructions that, when executed by the one or more processors, causes the one or more processors to;

obtain first image data corresponding to an image of optically encoded information received via a lens unit that causes controlled spherical aberration;

perform first processing on the first image data;

responsive to the first processing on the first image data not producing data corresponding to the optically encoded information, perform second

processing on the first image data to obtain second image data and perform the first processing on the second image data; and

responsive to the first processing on the second image data not producing the data corresponding to the optically encoded information, perform third processing on the first image data to obtain third image data and perform the first processing on the third image data;

wherein the lens unit causes predetermined spherical aberration blurring in the image of the optically encoded information.

20. The image processing system of claim 19 wherein the second processing includes deconvolution processing.

21. The image processing system of claim 19 wherein the second processing includes Weiner filter deconvolution processing.

22. The image processing system of claim 21 wherein the Weiner filter deconvolution processing is performed using data corresponding to a point spread function of the lens unit.

23. The image processing system of claim 21 wherein the Weiner filter deconvolution processing is performed using data corresponding to a near-field point spread function of the lens unit.

24. The image processing system of claim 21 wherein the Weiner filter deconvolution processing is performed using a one-dimensional deconvolution kernel.

25. The image processing system of claim 19 wherein the third processing includes deconvolution processing.

26. The image processing system of claim 19 wherein the third processing includes Weiner filter deconvolution processing.

27. The image processing system of claim 26 wherein the Weiner filter deconvolution processing is performed using data corresponding to a point spread function of the lens unit.

28. The image processing system of claim 27 wherein the Weiner filter deconvolution processing is performed using data corresponding to a near-field point spread function of the lens unit.

29. The image processing system of claim 27 wherein the Weiner filter deconvolution processing is performed using two one-dimensional deconvolution kernels.

30. The image processing system of claim 27 wherein the Weiner filter deconvolution processing is performed using a first deconvolution kernel matrix and a second deconvolution kernel matrix that is orthogonal to the first deconvolution kernel matrix.

31. The image processing system of claim 30 wherein the second deconvolution kernel matrix corresponds to the first deconvolution kernel matrix rotated by ninety degrees.

32. The image processing system of claim 19 wherein the optically encoded information includes a one-dimensional barcode symbol.

33. The image processing system of claim 19 wherein the optically encoded information includes a two-dimensional machine-readable symbol.

34. The image processing system of claim 19 wherein the lens unit causes more near-field spherical aberration blurring than far-field spherical aberration blurring.

35. The image processing system of claim 19, further comprising:

the lens unit.

36. The image processing system of claim 19 wherein the lens unit produces spherical aberration blurring such that offsetting fifth order effects are added to third order solutions to a spherical aberration equation.

37. An imager, comprising:

a lens unit that produces predetermined spherical aberration blurring, the lens unit producing spherical aberration blurring such that offsetting fifth order effects are added to the third order solutions to a spherical aberration equation; and

an image sensor that obtains images through the lens unit and produces corresponding image data.

38. The imager of claim 37 wherein the lens unit includes a first lens, a second lens, a third lens, and a diaphragm disposed between the first lens and the second lens.

39. The imager of claim 38 wherein the first lens is a biconvex lens, the second lens is a convex-concave lens, and the third lens is a biconvex lens.

40. The imager of claim 39, further comprising:

an aimer that produces a visible marker.

41. The imager of claim 40, further comprising:

a light source that produces light.

42. The imager of claim 41, further comprising:

a controller that controls operation of the image sensor, the aimer, and the light source.

43. The imager of claim 37 wherein respective points of an optical field entering the lens unit that are offset by respective angles from an optical axis of the lens unit converge in respective regions of an image plane of the image sensor.

44. An imager, comprising:

a lens unit that produces predetermined spherical aberration blurring, the lens unit producing spherical aberration blurring with third order solutions to a spherical aberration equation;

an image sensor that obtains images through the lens unit and produces corresponding image data;

and one or more processors; and

one or more processor-readable storage media storing processor-executable instructions that, when executed by the one or more processors, cause the one or more processors to;

obtain first image data corresponding to an image of optically encoded information received via the lens unit;

perform first processing on the first image data;

responsive to the first processing on the first image data not producing data corresponding to the optically encoded information, perform second processing on

the first image data to obtain second image data and perform the first processing on the

second image data.

45. The imager of claim 44 wherein the lens unit includes a first lens, a second lens, a third lens, and a diaphragm disposed between the first lens and the second lens.

46. The imager of claim 45 wherein the first lens is a biconvex lens, the second lens is a convex-concave lens, and the third lens is a biconvex lens.

47. The imager of claim 46, further comprising:

an aimer that produces a visible marker.

48. The imager of claim 47, further comprising:

a light source that produces light.

49. The imager of claim 48, further comprising:

a controller that controls operation of the image sensor, the aimer, and the light source.

50. The imager of claim 49 wherein respective points of an optical field entering the lens unit that are offset by respective angles from an optical axis of the lens unit converge in respective regions of an image plane of the image sensor.