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

• US 20070071320A1
• Filed: 09/20/2006
• Published: 03/29/2007
• Est. Priority Date: 09/20/2005
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Inventors: Yada, Shinichi
• Granted Patent: US 8,061,615 B2
• Time in Patent Office: Days
• US Class Current: 382/181
• 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;

selecting three center points that constitute apices of a right angled isosceles triangle from among the identified center point positions;

extracting for a feature of a two-dimensional code from a two-dimensional code region defined by the position detection patterns corresponding to the selected center points, or a peripheral region thereof, and

determining whether a two-dimensional code exists in the two-dimensional code region when the feature of a two-dimensional code is extracted.

2. The two-dimensional code detection method of claim 1, wherein the extracting comprises extracting as the feature a previously standardized blank region that exists in the peripheral region.

3. The two-dimensional code detection method of claim 2, wherein the blank region is a blank region that exists adjacent to at least one of the short sides of the right angled isosceles triangle of the two-dimensional code region.

4. The two-dimensional code detection method of claim 3, 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 at a side of the one of the short sides of the right angled isosceles triangle 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 then the region is determined to be a blank region.

5. The two-dimensional code detection method of claim 3, wherein a virtual region is set inside by a predetermined distance from the outer periphery of the two-dimensional code region in a region at a side of the one of the short sides of the right angled isosceles triangle of the two-dimensional code region, and if 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.

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

7. The two-dimensional code detection method of claim 6, 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.

8. The two-dimensional code detection method of claim 6, 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.

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

10. The two-dimensional code detection method of claim 1, wherein the extracting comprises extracting as the feature a ratio or difference between a number of white pixels and a number of black pixels in a region of the two-dimensional code region.

11. The two-dimensional code detection method of claim 10, wherein in the region of the two-dimensional code region the number of white pixels is substantially equal to the number of black pixels.

12. The two-dimensional code detection method of claim 1, wherein the extracting comprises extracting as the feature a number of white-black inversion times when the two-dimensional code region is scanned in a predetermined direction is within a predetermined range.

13. The two-dimensional code detection method of claim 1, further comprising:

selecting a further three center points which constitute apices of a right angled isosceles triangle from among the identified center point positions and are a different combination of center points from the three center points;

extracting for a feature of a two-dimensional code from a two-dimensional code region defined by the position detection patterns corresponding to the selected center points, and a peripheral region thereof; and

determining whether a two-dimensional code exists in the two-dimensional code region when the feature of a two-dimensional code is extracted; and

sequentially detecting a plurality of two-dimensional codes.

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

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

20. 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.

14. 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;

a feature extracting section that selects three center points that constitute apices of a right angled isosceles triangle from among the identified center point positions identified by the reference position identification section, and extracts for a feature of a two-dimensional code from a two-dimensional code region defined by the position detection patterns corresponding to the selected center points, and the peripheral region thereof; and

a determination section that determines whether a two-dimensional code exists in the two-dimensional code region when the feature of a two-dimensional code is extracted by the feature extraction section.

15. The two-dimensional code detection device of claim 14, further comprising a decoding section that decodes a two-dimensional code detected by the detection device.

16. The two-dimensional code detection device of claim 15, 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.

17. A 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;

selecting three center points that constitute apices of a right angled isosceles triangle from among the identified center point positions;

extracting for a feature of 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

determining whether a two-dimensional code exists in the two-dimensional code region when the feature of a two-dimensional code is extracted.

21. 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 three image regions, from all of the identified image regions, that form a right angled isosceles triangle figure by connecting the centers thereof to one another with a line so as to be respective position detection patterns of a two-dimensional code, and a region specified by the three position detection patterns of a two-dimensional code.

22. The two-dimensional code detection method of claim 21, further comprising setting in advance the size of the right angled isosceles triangle obtained by connecting the centers to one another with a line.

23. The two-dimensional code detection method of claim 21, 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 the vertical direction of the read image data.

24. The two-dimensional code detection method of claim 21, further comprising setting in advance a region where a two-dimensional code exists in the read image data.

25. The two-dimensional code detection method of claim 21, further comprising setting in advance the number of two-dimensional codes included in the read image data.

26. 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 detection section that detects three image regions, from all of the image regions that are identified by the identifying section, with which form a right angled isosceles triangle figure by connecting the centers thereof to one another with a line so as to be respective position detection patterns of a two-dimensional code, and detects a region specified by the three position detection patterns of a two-dimensional code.

27. A data signal embodied in a carrier wave for causing a computer to perform a process 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 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;

selecting three center points that constitute apices of a right angled isosceles triangle from among the identified center point positions;

extracting for a feature of a two-dimensional code from a two-dimensional code region defined by the position detection patterns corresponding to the selected center points, or a peripheral region thereof; and

determining whether a two-dimensional code exists in the two-dimensional code region when the feature of a two-dimensional code is extracted.