Code type determining method and code boundary detecting method

• US 20050121520A1
• Filed: 05/26/2004
• Published: 06/09/2005
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Noda, Tsugio, Chiba, Hirotaka, Yamaguchi, Nobuyasu, Takakura, Hiroyuki
• Granted Patent: US 7,636,483 B2
• Time in Patent Office: Days
• US Class Current: 235/462.90
• 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 7/1452 detecting bar code edges

Abstract

A code type determining method comprises a block selecting step of selecting input image data in units of rectangular blocks, a block determining step of determining whether or not the selected block satisfies a predetermined condition, and a code determining step of determining a type of code included in the block which satisfies the predetermined condition.

Claims

1. A code type determining method, comprising:

a block selecting step of selecting input image data in units of rectangular blocks;

a block determining step of determining whether or not the selected block satisfies a predetermined condition; and

a code determining step of determining a type of code included in the block which satisfies the predetermined condition.

2. The code type determining method according to claim 1, wherein:

a distinction between one-dimensional code and two-dimensional code is made as a type of code in said code determining step.

3. The code type determining method according to claim 2, further comprising:

a rotation detecting step of determining whether or not the one-dimensional code is in a rotated state when the type of the code is determined to be one-dimensional code.

4. The code type determining method according to claim 1, wherein:

whether or not dispersion of grayscale values of pixels within a block is within a predetermined range is determined as the predetermined condition in said block determining step.

5. The code type determining method according to claim 1, wherein:

whether or not a ratio of black pixels to white pixels within a block is within a predetermined range is determined as the predetermined condition in said block determining step.

6. The code type determining method according to claim 1, wherein

whether a number of edges at each of which a grayscale value of a pixel suddenly changes in a line in a horizontal direction or a vertical direction within a block is within a predetermined range is determined as the predetermined condition and/or a code type determination condition in said block determining step and/or said code determining step.

7. The code type determining method according to claim 1, wherein:

whether a correlation of grayscale values of pixels between two or more horizontal lines, and/or between two or more vertical lines within a block is within a predetermined range is determined as the predetermined condition and/or a code type determination condition in said block determining step and/or said code determining step.

8. A method detecting a boundary of two-dimensional code where data put into cells is arranged in a two-dimensional state, comprising:

a first white successive length detecting step of scanning input image data, and detecting a successive length of white cells;

a second white successive length detecting step of scanning the input image data in a direction which intersects with a first white successive length, and detecting a successive length of white cells, which has an intersection with the first white successive length, and exceeds a predetermined length; and

a boundary detecting step of detecting an intersection of the first white successive length and a second white successive length as a code boundary position.

9. The code boundary detecting method according to claim 8, wherein:

the input image data is scanned in an upward, downward, leftward, or rightward direction from a point within a code in correspondence with a position of the code, which is identified beforehand, in said first white successive length detecting step; and

an upward, downward, leftward, or rightward code boundary is detected in said boundary detecting step.

10. The code boundary detecting method according to claim 8, further comprising

a cell width detecting step of detecting a cell width, wherein

a successive length is decided by using the detected cell width as a reference in detection of the successive length of white cells.

11. The code boundary detecting method according to claim 10, wherein:

said cell width detecting step comprises

a step of scanning input image data in an upward, downward, leftward, or rightward direction from a point within a code in correspondence with a position of the code, which is identified beforehand, and creating a histogram which indicates a frequency of a successive length of white cells and/or a successive length of black cells,

a step of deciding a minimum successive length as a cell width among successive lengths having a frequency equal to or greater than a predetermined value in the histogram.

12. The code boundary detecting method according to claim 8, further comprising

a threshold value deciding step of deciding a threshold value used in detection of the successive length of white cells, wherein

a cell having a grayscale value equal to or larger than the threshold value is detected as a white cell.

13. The code boundary detecting method according to claim 12, wherein

in said first white successive length detecting step,

said threshold value deciding step is repeated for each scanning at a predetermined distance when the input image data is scanned, and

a cell having a grayscale value equal to or larger than the threshold value updated by the repetition is detected as a white cell.

14. The code boundary detecting method according to claim 13, wherein

said threshold value deciding step comprises

a step of creating a histogram which indicates frequencies of grayscale values of cells within a predetermined range,

a step of obtaining a first grayscale value corresponding to a peak having a frequency equal to or greater than a predetermined value on a side of a large grayscale value in the histogram,

a step of obtaining a second grayscale value corresponding to a peak having a frequency equal to or greater than a predetermined value on a side of a low grayscale value, and

a step of deciding an average value of the first grayscale value and the second grayscale value as a threshold value.

15. The code boundary detecting method according to claim 8, wherein

a comparison is made among grayscale values of an observed cell and its peripheral cells, and a cell having a large grayscale value is detected as a white cell if a difference among the grayscale values is equal to or greater than a predetermined value, in detection of the successive length of white cells.

16. A computer-readable portable storage medium, which is used by a computer determining a type of a code included in input image data, and on which is recorded a program for causing the computer to execute a process, the process comprising:

a step of selecting input image data in units of rectangular blocks;

a step of determining whether or not the selected block satisfies a predetermined condition; and

a step of determining a type of code included in the block which satisfies the predetermined condition.

17. The computer-readable portable storage medium according to claim 16, the process further comprising

a step of determining whether or not the one-dimensional code is in a rotated state if the type of the code is determined to be the one-dimensional code.

18. A computer-readable portable storage medium, which is used by a computer detecting a boundary of two-dimensional code where data put into cells is arranged in a two-dimensional state, and on which is recorded a program for causing the computer to execute a process, the process comprising:

a first white successive length detecting step of scanning input image data, and detecting a successive length of white cells;

a second white successive length detecting step of scanning the input image data in a direction which intersects with a first white successive length, and detecting a successive length of white cells, which has an intersection with the first white successive length, and exceeds a predetermined length; and

a boundary detecting step of detecting an intersection of the first white successive length and a second white successive length as a code boundary position.