Detection method of two-dimensional code, detection device for the same, and storage medium storing detection program for the same

• US 8,061,615 B2
• Filed: 09/20/2006
• Issued: 11/22/2011
• Est. Priority Date: 09/20/2005
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Yada, Shinichi
• Primary Examiner(s): Le; Thien M.
• Assistant Examiner(s): Stanford; Christopher
• Application Number:
  US11/523,570
• Publication Number:
  US 20070071320A1
• Time in Patent Office: 1,889 Days
• Field of Search: 235/462.09, 235/462.1, 235/462.11
• US Class Current: 235/462.08
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1456 determining the orientation of the optical code with respect to the reader and correcting therefore

Abstract

A method for detecting a two-dimensional code in which three position detection patterns are provided in positions corresponding to respective apices of a right angled isosceles triangle, and a data region is provided in a region defined by the position detection patterns is provided. The method includes detecting plural position detection patterns included in an image; identifying center points of the detected position detection patterns; selecting, from among the center points that positions are identified, three center points that constitute apices of a right angled isosceles triangle; extracting a feature as a two-dimensional code from a two-dimensional code region defined by the position detection patterns corresponding to the selected center points, or the peripheral region thereof; and in case where the feature as a two-dimensional code is extracted, determining that a two-dimensional code exists in the two-dimensional code region.

Claims

1. A method for detecting a two-dimensional code of three position detection patterns provided in positions corresponding to respective apices of a right angled isosceles triangle, and a data region is provided in a region defined by the position detection patterns, the method comprising:

detecting a plurality of position detection patterns included in an image;

identifying positions of the center points of the detected position detection patterns;

detecting groups of three center points, the three center points of each group constituting apices of a corresponding right angled isosceles triangle;

detecting, from among the groups of three center points, combinations of three center points, the three center points of each combination being included in a corresponding same two-dimensional code from among the identified center point positions, by

defining a candidate two-dimensional code region as a square formed by a combination of three center points,

setting a virtual line that forms a square that is separated by a predetermined distance from an outer periphery of the candidate two-dimensional code region, and

determining that a previously standardized blank region exists along the virtual line if the proportion of white pixels to the total number of pixels on the virtual line exceeds a threshold, and

determining the combination of three center points that forms the candidate two-dimensional code region with the virtual line having the blank region being included in the corresponding same two-dimensional code; and

determining the candidate two-dimensional code region in the combination of three center points included in the corresponding same two-dimensional code as a two-dimensional code region to be decoded.

2. The two-dimensional code detection method of claim 1, wherein the blank region is a region that exists around all four sides of the two-dimensional code region.

3. The two-dimensional code detection method of claim 2, wherein a virtual line is set that is separated by a predetermined distance from the outer periphery of the two-dimensional code region in a region around all four sides of the two-dimensional code region, and if the proportion of white pixels to the total number of pixels on the virtual line exceeds a threshold a region is determined to be a blank region.

4. The two-dimensional code detection method of claim 3, wherein the threshold is a value which is determined according to a symbol size of the two-dimensional code.

5. The two-dimensional code detection method of claim 1, wherein the threshold value is a value which is determined according to a symbol size of the two dimensional code.

6. The two-dimensional code detection method of claim 2, wherein a virtual region inside by a predetermined distance from the outer periphery of the two-dimensional code region is set in a region around all sides of the two-dimensional code region, and when the proportion of white pixels to the total number of pixels in the virtual region exceeds a threshold it is determined to be a blank region.

7. The two-dimensional code detection method of claim 6, wherein the threshold is a value which is determined according to a symbol size of the two-dimensional code.

8. A method for detecting a two-dimensional code of three position detection patterns provided in positions corresponding to respective apices of a right angled isosceles triangle, and a data region is provided in a region defined by the position detection patterns, the method comprising:

detecting a plurality of position detection patterns included in an image;

identifying positions of the center points of the detected position detection patterns;

detecting groups of three center points, the three center points of each group constituting apices of a corresponding right angled isosceles triangle;

detecting, from among the groups of three center points, combinations of three center points, the three center points of each combination being included in a correspondence same two-dimensional code from among the identified center point positions, by

defining a candidate two-dimensional code region as a square formed by a combination of three center points,

setting a virtual region inside by a predetermined distance from the outer periphery of the candidate two-dimensional code region,

determining a previously standardized blank region exists in the virtual region if the proportion of white pixels to the total number of pixels in the virtual region exceeds a threshold region, and

determining the combination of three center points that forms the candidate two-dimensional code region with the virtual region having the blank region being included in the corresponding same two-dimensional code; and

determining the candidate two-dimensional code region in the combination of three center points included in the correspondence same two-dimensional code as a two-dimensional code region to be decoded.

9. The two-dimensional code detection method of claim 8, wherein the threshold is a value which is determined according to a symbol size of the two-dimensional code.

10. A two-dimensional code detection device for detecting a two-dimensional code of three position detection patterns provided in positions corresponding to respective apices of a right angled isosceles triangle, and a data region is provided in a region defined by the position detection patterns, the device comprising:

a reference position identification section that detects the position detection patterns included in an image, and identifies center points of the detected position detection patterns;

detecting groups of three center points, the three center points of each group constituting apices of a corresponding right angled isosceles triangle;

a feature extracting section that detects, from among the groups of three center points, combinations of three center points, the three center points of each combination being included in a corresponding same two-dimensional code from among the identified center point positions identified by the reference position identification section, by being configured to;

define a candidate two-dimensional code region as a square formed by a combination of three center points,

set a virtual line that forms a square that is separated by a predetermined distance from an outer periphery of the candidate two-dimensional code region, and

determine that a previously standardized blank region exists along the virtual line if the proportion of white pixels to the total number of pixels on the virtual line exceeds a threshold, and

determine the combination of three center points that forms the candidate two-dimensional code region with the virtual line having the blank region being included in the corresponding same two-dimensional code; and

a determination section that determines the candidate two-dimensional code region in the combination of three center points included in the corresponding same two-dimensional code as a two-dimensional code region to be decoded by the feature extraction section.

11. The two-dimensional code detection device of claim 10, further comprising a decoding section that decodes the two-dimensional code detected by the detection device.

12. The two-dimensional code detection device of claim 11, further comprising a position correction section that, before the decoding of the two-dimensional code by the decoding section, corrects a rotation position of the two-dimensional code such that pixel arrangement orientation of the two-dimensional code is parallel or orthogonal to a scanning direction.

13. A non-transitory storage medium storing a program to detect, by a computer, a two-dimensional code of three position detection patterns provided in positions corresponding to respective apices of a right angled isosceles triangle, and a data region is provided in a region defined by the position detection patterns, the program causing the computer to perform a two-dimensional code detection process comprising:

detecting a plurality of position detection patterns included in a binary image;

identifying positions of the center points of the detected position detection patterns;

detecting groups of three center points, the three center points of each group constituting apices of a corresponding right angled isosceles triangle;

detecting, from among the groups of three center points, combinations of three center points, the three center points of each combination being included in a corresponding same two-dimensional code from among the identified center point positions, by

defining a candidate two-dimensional code region as a square formed by a combination of three center points,

setting a virtual line that forms a square that is separated by a predetermined distance from an outer periphery of the candidate two-dimensional code region, and

determining that a previously standardized blank region exists along the virtual line if the proportion of white pixels to the total number of pixels on the virtual line exceeds a threshold, and

determining the combination of three center points that forms the candidate two-dimensional code region with the virtual line having the blank region being included in the corresponding same two-dimensional code; and

determining the candidate two-dimensional code region in the combination of three center points included in the corresponding same two-dimensional code as a two-dimensional code region to be decoded.

14. A two-dimensional code detection method, comprising:

storing in a storage section in advance a contrast pattern of a position detection pattern that is disposed at three corners of a square;

identifying all image regions that match the contrast pattern on the basis of read image data obtained by reading a document; and

detecting groups of three image regions from all of the identified image regions, the three image regions of each group constituting apices of a corresponding right angled isosceles triangle figure by connecting the centers thereof to one another with a line;

detecting, from among the groups of three image regions, combinations of three image regions, the three image regions of each combination being included in a corresponding same two-dimensional code, by

defining a candidate two-dimensional code region as a square formed by a combination of three center points,

setting a virtual line that forms a square that is separated by a predetermined distance from an outer periphery of the candidate two-dimensional code region, and

determining that a previously standardized blank region exists along the virtual line if the proportion of white pixels to the total number of pixels on the virtual line exceeds a threshold, and

determining the combination of three center points that forms the candidate two-dimensional code region with the virtual line having the blank region being included in the corresponding same two-dimensional code; and

detecting, for each of the combinations, a region specified by the three position detection patterns as the two-dimensional code.

15. The two-dimensional code detection method of claim 14, further comprising setting in advance the size of the right angled isosceles triangle obtained by connecting the centers to one another with a line.

16. The two-dimensional code detection method of claim 14, further comprising setting in advance an orientation angle of the right angled isosceles triangle obtained by connecting the centers to one another with a line to a vertical direction of the read image data.

17. The two-dimensional code detection method of claim 14, further comprising setting in advance a region where the two-dimensional code exists in the read image data.

18. The two-dimensional code detection method of claim 14, further comprising setting in advance a number of two-dimensional codes included in the read image data.

19. A two-dimensional code detection device, comprising:

a storage section that stores in advance a contrast pattern of a position detection pattern that is disposed at three corners of a square;

a position detection pattern identifying section that, on the basis of read image data obtained by reading a document, identifies all image regions that match the contrast pattern; and

a group detection section that detects groups of three image regions, the three image regions of each group constituting apices of a corresponding right angled isosceles triangle figure by connecting the centers thereof to one another with a line;

a combination detection section that detects, from among the groups of three image regions, combinations of three image regions, the three image regions of each combination being included in a corresponding same two-dimensional code, by being configured to;

define a candidate two-dimensional code region as a square formed by a combination of three center points,

set a virtual line that forms a square that is separated by a predetermined distance from an outer periphery of the candidate two-dimensional code region, and

determine that a previously standardized blank region exists along the virtual line if the proportion of white pixels to the total number of pixels on the virtual line exceeds a threshold, and

determine the combination of three center points that forms the candidate two-dimensional code region with the virtual line having the blank region being included in the corresponding same two-dimensional code;

wherein the

detect, for each of the combinations, a region specified by the three position detection patterns as the two-dimensional code.