Method and apparatus for recognizing boundary line in an image information

• US 8,582,888 B2
• Filed: 02/14/2008
• Issued: 11/12/2013
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tanaka, Hiroshi, Nakajima, Kenji, Minagawa, Akihiro, Takebe, Hiroaki, Fujimoto, Katsuhito
• Primary Examiner(s): Le, Vu
• Assistant Examiner(s): WOLDEMARIAM, AKLILU K
• Application Number:
  US12/071,050
• Publication Number:
  US 20080199082A1
• Time in Patent Office: 2,098 Days
• Field of Search: 382/151, 382/181, 382/182, 382/186, 382/190, 382/199, 382/202, 382/218
• US Class Current: 382/182
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/412 Layout analysis of documents structured with printed lines or input boxes, e.g. business forms or tables

Abstract

According to an aspect of an embodiment, a method of detecting boundary line information contained in image information comprising a plurality of pixels in either one of first and second states, comprising: detecting a first group of pixels in the first state disposed continuously in said image information to determine first line information and detecting a second group of pixels in the first state disposed adjacently with each other and surrounded by pixels in the second state to determine edge information based on the contour of the second group of pixels; and determining the boundary line information on the basis of the information of the relation of relative position of the line information and the edge information and the size of the first and second group of pixels.

Claims

1. A method of detecting ruled line information contained in image information including a plurality of pixels in either one of first and second states executed by a computer, the method comprising:

detecting, by the computer a first group of pixels in the first state disposed linearly continuously in said image information;

determining, by the computer, first line information based on the first group of pixels;

detecting, by the computer, a second group of pixels in the first state disposed adjacently with each other and surrounded by pixels in the second state;

determining, by the computer, edge information based on a contour of the second group of pixels;

determining, by the computer, at least one type of ruled line candidate in a table in a document image based on a positional relationship between the first line information and the edge information; and

generating the ruled line information in accordance with the at least one type of ruled line candidate.

2. The method according to claim 1, wherein said determining the at least one type of ruled line candidate determines a first type of ruled line candidate where a first line, indicated by the first line information, is sandwiched by a pair of edges indicated by the edge information and a distance among the first line and the pair of edges is less than a predetermined value.

9. The apparatus according to claim 2, wherein said determining of the at least one type of ruled line candidate determines a second type of ruled line candidate where a second line, indicated by the first line information, is substantially parallel and adjacent to a first edge, indicated by the edge information, within a predetermined distance from the edge.

10. The apparatus according to claim 9, wherein said determining of the at least one type of ruled line candidate determines a third type of ruled line candidate where a second edge is indicated by the edge information and the first line information does not indicate any line within a predetermined distance from the second edge.

11. The apparatus according to claim 1, wherein said determining of the edge information includes

smoothing the image information to produce a smoothed image with the contour;

and

extracting the edge information from the contour of the smoothed image.

12. The apparatus according to claim 1, wherein said determining of the at least one type of ruled line candidate includes superimposing a first line, indicated by the first line information, on at least one edge indicated by the edge information.

3. An apparatus for detecting ruled line information contained in image information including a plurality of pixels in either one of first and second states, comprising:

a memory storing image information; and

a processor executing a process comprising;

detecting a first group of pixels in the first state disposed linearly continuously in said image information;

determining first line information based on the first group of pixels;

detecting a second group of pixels in the first state disposed adjacently with each other and surrounded by pixels in the second state

determining edge information based on the contour of the second group of pixels;

determining at least one type of ruled line candidate in a table in a document image based on a positional relationship between the first line information and the edge information; and

generating the ruled line information in accordance with the at least one type of ruled line candidate.

4. The apparatus according to claim 3, wherein the determining of the at least one type of ruled line candidate determines a first type of ruled line candidate where a first line, indicated by the first line information, is sandwiched by a pair of edges, indicated by the edge information, and a distance among the first line and the pair of edges is less than a predetermined value.

5. The apparatus according to claim 4, wherein the determining of the at least one type of ruled line candidate determines a second type of ruled line candidate where a second line, indicated by the first line information, is substantially parallel and adjacent to a first edge, indicated by the edge information, within a predetermined distance from the edge.

6. The apparatus according to claim 5, wherein the determining of the at least one type of ruled line candidate determines a third type of ruled line candidate where a second edge is indicated by the edge information and the first line information does not indicate any line within a predetermined distance from the second edge.

7. The apparatus according to claim 3, wherein the determining of the edge information includes

smoothing the image information to produce a smoothed image with the contour;

and

extracting the edge information from the contour of the smoothed image.

8. The apparatus according to claim 3, wherein the determining of the at least one type of ruled line candidate includes superimposing a first line, indicated by the first line information, on at least one edge indicated by the edge information.