Image analysis – Pattern recognition – Feature extraction
Reexamination Certificate
1997-04-07
2001-12-11
Ahmed, Samir (Department: 2623)
Image analysis
Pattern recognition
Feature extraction
C382S204000
Reexamination Certificate
active
06330360
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an image processing apparatus and method for extracting ruled lines present in the image of an entered original.
When ruled lines are to be extracted in the image of an original having a plurality of such lines using a conventional image processing apparatus, the conventional practice is to calculate a density histogram of the image of the original and extract the ruled lines based upon the density histogram calculated, or to extract the ruled lines based upon continuity of pixels in the image of the original.
With the conventional image processing apparatus described above, however, ruled lines in the image of an original cannot be extracted accurately or characters are mistakenly extracted as ruled lines if the ruled lines are skewed, blurred, positionally displaced or are of different sizes, by way of example.
Further, there are methods available in which the extraction of ruled lines on an original image having a specific format is performed with greater accuracy by acquiring information indicative of positions of the ruled lines from the format. However, such methods cannot be applied to an original image other than one having the specific format.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an image processing apparatus and method in which images of originals having formats of a plurality of types can be identified and ruled lines present in the original image can be extracted based upon the format identified, thereby making it possible to extract ruled lines more accurately.
According to the present invention, the foregoing object is attained by providing an image processing apparatus for extracting ruled lines present in an entered original image, comprising storage means for storing ruled-line information relating to ruled lines present in each original image of original images having formats of a plurality of types, identification means for identifying, based upon consecutive pixels present in the entered original image, the format of this original image as one format of formats stored in the storage means, and extraction means for extracting the ruled lines present in the entered original image based upon the ruled-line information of the format identified by the identification means.
In a preferred embodiment, the apparatus further comprises correction means for correcting skewing of the entered original image. Correcting for skewing of the original image makes it possible to extract ruled lines more accurately.
In a preferred embodiment, the ruled-line information includes key ruled-line information serving as a key for identifying formats of a plurality of types.
In a preferred embodiment, the identification means includes acquisition means for acquiring consecutive pixels defining a length greater than a predetermined length based upon a relative positional relationship of consecutive pixels present in the entered original image, and comparison means for comparing the consecutive pixels acquired by the acquisition means with the key ruled-line information, wherein the identification means identifies the format of the entered original image as one format of formats stored in the storage mean based upon results of comparison performed by said comparison means.
In a preferred embodiment, the apparatus further comprises re-acquisition means for re-acquiring consecutive pixels defining a length greater than the predetermined length present in the entered original image based upon the key ruled-line information in a case where numbers of consecutive pixels acquired by the acquisition means are less than the numbers of consecutive pixels in the key ruled-line information of the format identified by the identification means. Providing the re-acquisition means makes it possible to acquire blurred consecutive pixels.
In a preferred embodiment, the key ruled-line information indicates ruled lines having a prescribed direction.
According to the present invention, the foregoing object is attained by providing an image processing method for extracting ruled lines present in an entered original image, comprising a storage step of storing, on a storage medium, ruled-line information relating to ruled lines present in each original image of original images having formats of a plurality of types, an identification step of identifying, based upon consecutive pixels present in the entered original image, the format of this original image as one format of formats stored on the storage medium at the storage step, and an extraction step of extracting the ruled lines present in the entered original image based upon the ruled-line information of the format identified by the identification step.
According to the present invention, the foregoing object is attained by providing a computer readable memory storing program codes of image processing, comprising a program code of a storage step of storing, on a storage medium, ruled-line information relating to ruled lines present in each original image of original images having formats of a plurality of types, a program code of an identification step of identifying, based upon consecutive pixels present in the entered original image, the format of this original image as one format of formats stored on the storage medium at the storage step, and a program code of an extraction step of extracting the ruled lines present in the entered original image based upon the ruled-line information of the format identified at the identification step.
Thus, in accordance with the present invention as described above, it possible to provide an image processing apparatus and method in which images of originals having formats of a plurality of types can be identified and ruled lines present in the original image can be extracted based upon the format identified, thereby making it possible to extract ruled lines more accurately.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.
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patent: 5048107 (1991-09-01), Tachikawa
patent: 5075895 (1991-12-01), Bessho
patent: 5101448 (1992-03-01), Kawachiya et al.
patent: 5129012 (1992-07-01), Abe
patent: 5159667 (1992-10-01), Borrey et al.
Ahmed Samir
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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