System for locating and determining the orientation of bar codes in a two-dimensional image

• US 5,296,690 A
• Filed: 09/26/1991
• Issued: 03/22/1994
• Est. Priority Date: 03/28/1991
• Status: Expired due to Term

• Current Assignee: Omniplanar, Inc. (Honeywell International Inc.)
• Original Assignee: Omniplanar, Inc. (Honeywell International Inc.)
• Inventors: Batterman, Eric P., Chandler, Donald G.
• Primary Examiner(s): Willis, Davis L.
• Assistant Examiner(s): Sikorski, Edward
• Application Number:
  US07/766,909
• Time in Patent Office: 908 Days
• Field of Search: 235/454, 235/462, 235/471, 235/472, 235/470, 250/566, 250/568, 356/71, 382/10, 382/48
• US Class Current: 235/462.1
• CPC Class Codes: G06K 7/1093 sensing, after transfer of the image of the data-field to an intermediate store, e.g. storage with cathode ray tube
• CPC Class Codes: G06K 7/1443 locating of the code in an image
• CPC Class Codes: G06K 7/1456 determining the orientation of the optical code with respect to the reader and correcting therefore

Abstract

A bar code reader includes an image capture means for storing a two dimensional image in memory, which stored image may include a bar code symbol within the field of view of said image. The present bar code reader further includes method and apparatus for determining the location and orientation of said bar code symbol within the field of view of said image, and then filtering said located and oriented bar code symbol along an axis perpendicular to said detected orientation. Thereafter, the filtered bar code symbol is scanned and applied to a decoder to produce a decoded bar code output.

Claims

1. A method for reading a bar code symbol, said method comprising:

capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

locating an area within the field of view of said stored two dimensional image, said located area being likely to contain a bar code image, said locating step including the step of comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments;

examining the image within said located area to determine the orientation of said bar code image within said located area of said stored two dimensional image;

filtering said bar code image along an axis substantially perpendicular to said detected orientation of said bar code image; and

scanning said filtered bar code image to read out information contained in said bar code image.

2. A method for reading a bar code symbol, said method comprising:

capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

locating an area within the field of view of said stored two dimensional image, said located area being likely to contain a bar code image, said locating step including the step of comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments;

examining the image within said located area to determine the orientation of said bar code image within said located area of said stored two dimensional image; and

scanning said located area along an angle substantially equal to said determined orientation of bar code image to read out information contained in said bar code image.

3. A method for reading a bar code symbol, said method comprising:

capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

a first image processing phase including locating an area within the field of view of said stored two dimensional image, said first processing phase including the step of comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments wherein said located area is more likely to contain a bar code image as compared to the other areas of said stored two dimensional image; and

a second image processing phase including scanning said located area of said stored two dimensional image to read out information contained in said bar code image.

4. A method for reading a bar code symbol, said method comprising:

capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

locating said bar code by comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments; and

scanning said stored two dimensional image in an omnidirectional manner in order to read out information contained in said stored two dimensional image of said bar code symbol.

5. A method in accordance with claim 4, wherein said step of scanning said stored two dimensional image in an omnidirectional manner further includes:

examining the image within said located area to determine the orientation of said bar code image within said located area of said stored two dimensional image.

6. A method in accordance with claim 5, wherein said step of scanning said stored two dimensional image in an omnidirectional manner further includes:

filtering said bar code image along an axis substantially perpendicular to said detected orientation of said bar code image.

7. A method in accordance with claim 6, wherein said step of scanning said stored two dimensional image in an omnidirectional manner further includes:

extracting sequential values from said bar code image to read out information contained in said bar code image.

8. An apparatus for reading a bar code symbol, said apparatus comprising:

means for capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

means for locating an area within the field of view of said stored two dimensional image, said located area being likely to contain a bar code image, said locating means including means for comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments;

means for examining the image within said located area to determine the orientation of said bar code image within said located area of said stored two dimensional image;

means for filtering said bar code image along an axis substantially perpendicular to said detected orientation of said bar code image; and

means for scanning said filtered bar code image to read out information contained in said bar code image.

9. An apparatus for reading a bar code symbol, said apparatus comprising:

means for capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

means for locating an area within the field of view of said stored two dimensional image, said located area being likely to contain a bar code image, said locating means including means for comparing tow substantially parallel scan line segments by comparing corresponding points of a function of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments;

means for examining the image within said located area to determine the orientation of said bar code image within said located area of said stored two dimensional image; and

means for scanning said located area along an angle substantially equal to said determined orientation of said bar code image to read out information contained in said bar code image.

10. An apparatus for reading a bar code symbol, said apparatus comprising:

means for capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

first phase image processing means including means for locating an area within the field of view of said stored two dimensional image, said first phase processing means including means for comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments, wherein said located area is more likely to contain a bar code image as compared to the other areas of said stored two dimensional image; and

second phase image processing means including means for scanning said located area of said stored two dimensional image to read out information contained in said bar code image.

11. An apparatus for reading a bar code symbol, said apparatus comprising:

means for capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

means for locating said bar code by comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of said two substantially parallel scan line segments, said function having a plurality of output points for each of said scan line segments; and

means for scanning said stored two dimensional image in an omnidirectional manner in order to read out information contained in said stored two dimensional image of said bar code symbol.

12. A method in accordance with claim 11, wherein said means for scanning said stored two dimensional image in an omnidirectional manner further includes:

means for examining the image within said located area to determine the orientation of said bar code image within said located area of said stored two dimensional image.

13. An apparatus in accordance with claim 12, wherein said means for scanning said stored two dimensional image in an omnidirectional manner further includes:

means for filtering said bar code image along an axis substantially perpendicular to said detected orientation of said bar code image.

14. An apparatus in accordance with claim 13, wherein said means for scanning said stored two dimensional image in an omnidirectional manner further includes:

means for extracting sequential values from said bar code image to read out information contained in said bar code image.

15. A method for reading a bar code symbol, said method comprising:

capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

locating and coarsely orienting an area within the field of view of said stored two dimensional image, said located and coarsely oriented area being likely to contain a bar code image;

examining the image within said located and coarsely oriented area by comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of substantially parallel scan line segments at a multiplicity of shifts of one of said scan line segments relative to said other of said scan line segments along the direction of said scan line segments to determine the fine orientation of said bar code image within said located and coarsely oriented area of said stored two dimensional image; and

filtering said bar code image along an axis substantially perpendicular to said detected fine orientation of said bar code image by shifting at least two said substantially parallel scan line segments into substantial alignment, and combining corresponding data points of at least two said shifted substantially parallel scan line segments.

16. A method for reading a bar code symbol in accordance with claim 15, further comprising:

scanning said fine oriented and bar code image along an angle substantially equal to said determined fine orientation of bar code image to read out information contained in said bar code image.

17. A method for reading a bar code symbol, said method comprising:

capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

locating and orienting an area by comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of substantially parallel scan line segments at a multiplicity of shifts of one of said scan line segments relative to said other of said scan line segments along the direction of said scan line segments within the field of view of said stored two dimensional image, said located and oriented area being likely to contain a bar code image and;

filtering said ar code image along an axis substantially perpendicular to said detected orientation of said bar code image by shifting at least two said substantially parallel scan line segments into substantial alignment, and combining corresponding data points of at least two said shifted substantially parallels scan lines segments.

18. A method for reading a bar code symbol in accordance with claim 17, further comprising:

scanning said located and oriented area along an angle substantially equal to said determined orientation of bar code image to read out information contained in said bar code image.

19. An apparatus for reading a bar code symbol, said apparatus comprising:

means for capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image;

means for locating and coarsely orienting an area within the field of view of said stored two dimensional image, said located and coarsely oriented area being likely to contain a bar code image;

means for examining the image within said located and coarsely oriented area to determine the fine orientation of said bar code image by comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of substantially parallel scan line segments at a multiplicity of shifts of one of said scan line segments relative to said other of said scan line segments along the direction of said scan line segments within said located and coarsely oriented area of said stored two dimensional image; and

means for filtering said bar code image along an axis substantially perpendicular to said detected fine orientation of said bar code image, said filtering means including means for shifting at least two said substantially parallel scan line segments into substantial alignment, and means for combining corresponding data points of at least two said shifted substantially parallel scan line segments.

20. An apparatus for reading a bar code symbol in accordance with claim 19, further comprising:

means for scanning said fine oriented and bar code image along an angle substantially equal to said determined fine orientation of bar code image to read out information contained in said bar code image.

21. An apparatus of reading a bar code symbol, said apparatus comprising:

means for capturing and storing a two dimensional image in a memory, said stored two dimensional image containing an image of a bar code symbol anywhere within the field of view of said stored two dimensional image; and

means for locating and orienting an area by comparing two substantially parallel scan line segments by comparing corresponding points of a function of the reflectance waveforms of substantially parallel scan line segments at a multiplicity of shifts of one of said scan line segments relative to said other of said scan line segments along the direction of said scan line segments within the field of view of said stored two dimensional image, said located and oriented area being likely to contain a bar code image; and

;

means for filtering said bar code image along an axis substantially perpendicular to said detected orientation of said bar code image, including means for shifting at least two said substantially parallel scan line segments into substantial alignment, and means for combining corresponding data points of at least two said shifted substantially parallel scan line segments.

22. An apparatus for reading a bar code symbol in accordance with claim 21, further comprising:

means for scanning said located and oriented area along an angle substantially equal to said determined orientation of said bar code image to read out information contained in said bar code image.