Correction method of document inclination angle

Details Correction method of document inclination angle Correction method of document inclination angle

1998-03-27

2001-10-09

Lee, Cheukfan (Department: 2722)

Facsimile and static presentation processing

Facsimile

Picture signal generator

C358S496000

Reexamination Certificate

active

06301022

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a correction method of document inclination angle for an image reading apparatus such as a scanner, facsimile device, digital copier in which a document is placed on an image reading position, and an image of the document is read, and specifically to an image reading apparatus in which, even when the placed document is inclined, it can be corrected.
In an image reading apparatus such as a scanner, facsimile device, digital copier in which a document is placed on an image reading position, and an image of the document is read, there is a case in which the document is placed while being inclined. When the inclined document is read, for example, copied (image formation), as it is, there is a possibility that some portions of the image are lost.
Accordingly, in the conventional image reading apparatus, an inclination angle of the document is detected by detecting an inclination of a row of characters from image information obtained from the inclined document, and the inclination angle is corrected corresponding to obtained image information.
In the above method, in order to detect the inclination angle of the document, it is necessary that image information is read (pre-scanned) after the document is previously set on a reading position. Therefore, a long period of time is necessary for detecting the inclination angle, and thereby, image reading efficiency is lowered. Further, in order to detect the inclination of a character row, it takes a long time because complicated calculation is necessary, and further, cost is increased because many memories are used for calculation.
SUMMARY OF THE INVENTION
An object of the present invention is to shorten a time necessary for detecting the inclination angle of the document, and to increase the efficiency of image reading. Further, another object of the present invention is to shorten a time necessary for inclination angle correction, and to reduce a cost.
The above objects can be attained by the following structure.
In the structure, a correction method of the document inclination angle has the following steps: the first detection step to detect an edge of the document; the second detection step to find an inclination value corresponding to the inclination (&thgr;) of the document based on the detected document edge information, wherein the inclination of the document is the inclination of the document with respect to the first direction (X direction), which is the reference, and the second direction (Y direction) perpendicular to the first direction, and a correction step to correct the inclination with respect to the first direction and the second direction of the image data, wherein the correction step comprises the following processing: the first shift processing to shift the image data to one direction of the first direction and the second direction corresponding to the inclination value; and the second shift processing to shift the image data to another direction of the first direction and the second direction corresponding to the inclination value.


REFERENCES:
patent: 4618991 (1986-10-01), Tabata et al.
patent: 4687944 (1987-08-01), Mitsuka et al.
patent: 4759076 (1988-07-01), Tanaka et al.
patent: 4802229 (1989-01-01), Yamada
patent: 4953230 (1990-08-01), Kurosu
patent: 4975977 (1990-12-01), Kurosu et al.
patent: 5149977 (1992-09-01), Mita
patent: 5181260 (1993-01-01), Kurosu et al.
patent: 5191438 (1993-03-01), Katsurada et al.
patent: 0432723 (1991-06-01), None
patent: 61203781 (1986-09-01), None
patent: 8192939 (1996-07-01), None
patent: 95 12271 (1995-05-01), None
European Search Report EP 98 10 5835.
Patent Abstracts of Japan, Publication #08192939, Publication Abstracts of Japan, Publication date Jul. 30, 1996 (1 page).
Patent Abstacts of Japan, Publication #61203781, Publication date: Sep. 9, 1986.

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