Two-dimensional code recognition method
First Claim
1. A two-dimensional code recognition apparatus comprising:
- an image reading section for optically reading an image including a rectangular two-dimensional code figure and for converting the read image into image information of a dot matrix form corresponding to coordinates of reading points;
an image memory section for storing the image information produced by said image reading section;
an image processing section for extracting a part of the image information stored in said image memory section which corresponds to the two-dimensional code figure, and for detecting two-dimensional code data from the extracted part of the image information;
wherein said image processing section includes;
(i) edge point detecting means for detecting edge points forming an outline of the two-dimensional code figure by scanning rows and columns of the image information which are respectively separated by a predetermined number in column and row directions, (ii) straight line approximating means for performing an approximating operation of obtaining straight lines corresponding to the detected edge points by Hough transform and for determining two perpendicularly intersecting straight lines within a result of the Hough transform by a least square approximation, and (iii) specifying means for specifying the part of the image information corresponding to the two-dimensional code figure based on positions of the determined two perpendicularly intersecting straight lines.
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Abstract
According to a two-dimensional code recognition method of the present invention, first, a two-dimensional image is input in step S1, and an edge is detected in step S2. This edge detection is performed by scanning pixels on a scanning line every several dots. A straight line is extracted in accordance with the Hough transform and the least square approximation in step S3, and a combination of straight lines is selected in step S4. Then, the size of a figure is detected in step S5. In step S6, two remaining straight lines are extracted, and the figure is extracted. In step S7, matrix information is extracted from the extracted figure, and codes are recognized. The flow returns to the selection of a combination of straight lines in step S4 until the straight line detection and the figure recognition can be accurately performed in steps S5, S6, and S7.
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Citations
28 Claims
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1. A two-dimensional code recognition apparatus comprising:
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an image reading section for optically reading an image including a rectangular two-dimensional code figure and for converting the read image into image information of a dot matrix form corresponding to coordinates of reading points; an image memory section for storing the image information produced by said image reading section; an image processing section for extracting a part of the image information stored in said image memory section which corresponds to the two-dimensional code figure, and for detecting two-dimensional code data from the extracted part of the image information; wherein said image processing section includes;
(i) edge point detecting means for detecting edge points forming an outline of the two-dimensional code figure by scanning rows and columns of the image information which are respectively separated by a predetermined number in column and row directions, (ii) straight line approximating means for performing an approximating operation of obtaining straight lines corresponding to the detected edge points by Hough transform and for determining two perpendicularly intersecting straight lines within a result of the Hough transform by a least square approximation, and (iii) specifying means for specifying the part of the image information corresponding to the two-dimensional code figure based on positions of the determined two perpendicularly intersecting straight lines. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A two-dimensional code recognition apparatus comprising:
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an image reading section for optically reading an image including a rectangular two-dimensional code figure and for converting the read image into image information of a dot matrix form corresponding to coordinates of reading points; an image memory section for storing the image information produced by said image reading section; an image processing section for extracting a part of the image information stored in said image memory section, which corresponds to the two-dimensional code figure, and for detecting two-dimensional code data from the extracted part of the image information; wherein said image processing section includes;
(i) edge point detecting means for detecting edge points forming an outline of the two-dimensional code figure by scanning rows and columns of the image information which are respectively separated by a predetermined number in column and row directions, (ii) straight line approximating means for performing an approximating operation of obtaining straight lines corresponding to the detected edge points by Hough transform and for determining four perpendicularly intersecting straight lines within a result of Hough transform by a least square approximation, and (iii) specifying means for specifying the part of the image information corresponding to the two-dimensional code figure based on positions of the four perpendicularly intersecting straight lines. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A two-dimensional code recognition method comprising steps of:
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optically reading an image including a rectangular two-dimensional code figure and converting the read image into image information of a dot matrix form corresponding to coordinates of reading points; storing the image information in an image memory section; performing an image processing operation of extracting a part of the image information stored in said image memory section which corresponds to the two-dimensional code figure, and detecting two-dimensional code data from the extracted part of the image information; wherein said image processing step includes the substeps of (i) detecting edge points forming an outline of the two-dimensional code figure by scanning rows and columns of the image information which are respectively separated by a predetermined number in column and row directions, (ii) performing an approximating operation of obtaining straight lines corresponding to the detected edge points by Hough transform and determining two perpendicularly intersecting straight lines within a result of Hough transform by a least square approximation, and (iii) specifying the part of the image information corresponding to the two-dimensional code figure based on positions of the two perpendicularly intersecting straight lines. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A two-dimensional code recognition method comprising steps of:
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optically reading an image including a rectangular two-dimensional code figure and converting the read image into image information of a dot matrix form corresponding to coordinates of reading points; storing the image information in an image memory section; performing an image processing operation of extracting a part of the image information stored in said image memory section which corresponds to the two-dimensional code figure, and detecting two-dimensional code data from the extracted part of the image information; wherein said image processing step includes the substeps of (i) detecting edge points forming an outline of the two-dimensional code figure by scanning rows and columns of the image information which are respectively separated by a predetermined number in column and row directions, (ii) performing an approximating operation of obtaining straight lines corresponding to the detected edge points by Hough transform and determining four perpendicularly intersecting straight lines within a result of Hough transform by a least square approximation, and (iii) specifying the part of the image information corresponding to the two-dimensional code figure based on positions of the four perpendicularly intersecting straight lines. - View Dependent Claims (24, 25, 26, 27, 28)
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Specification