Apparatus for correcting skew, distortion and luminance when imaging books and the like
First Claim
1. A picture processing apparatus comprising:
- first edge detection means for detecting an edge of a document image from a picture obtained by imaging the document;
skew detection means for detecting a skew of the document from the edge detected by the first edge detection means;
rotation correction means for rotating the picture on the basis of the skew;
second edge detection means for detecting an edge of the document image from the picture rotated by the rotation correction means;
magnification calculation means for calculating a magnification of the picture from the edge detected by the second edge detection means;
height calculation means for calculating a height of the document from a reference plane on the basis of the edge detected by the second edge detection means; and
distortion correction means for correcting a distortion of the picture through magnification/reduction of the picture rotated by the rotation correction means on the basis of the magnification and the height of the document.
1 Assignment
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Accused Products
Abstract
An object of the invention is to correct a distortion due to inclination of a document and to correct a luminance.
First, an edge detection section detects an edge of a document image from a picture obtained by imaging the document. Then, a skew detection section detects a skew of the document from the edge. A rotation correction section causes the picture to rotate on the basis of the skew detected by the skew detection section. Subsequently, the edge detection section again extracts a document image edge from the picture rotated by the rotation correction section. Further, a height calculation section calculates from the edge a height of the document. Simultaneously, a magnification calculation section calculates from the edge a magnification of the picture. Next, a distortion correction section corrects a distortion by magnification/reduction of the picture rotated by the rotation correction section on the basis of the document height and the magnification. Lastly, a luminance correction section corrects the luminance of pixels of the distortion-corrected picture. Whereby, even when the document suffers from skew added thereto, distortion correction and luminance correction can be performed.
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Citations
10 Claims
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1. A picture processing apparatus comprising:
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first edge detection means for detecting an edge of a document image from a picture obtained by imaging the document; skew detection means for detecting a skew of the document from the edge detected by the first edge detection means; rotation correction means for rotating the picture on the basis of the skew; second edge detection means for detecting an edge of the document image from the picture rotated by the rotation correction means; magnification calculation means for calculating a magnification of the picture from the edge detected by the second edge detection means; height calculation means for calculating a height of the document from a reference plane on the basis of the edge detected by the second edge detection means; and distortion correction means for correcting a distortion of the picture through magnification/reduction of the picture rotated by the rotation correction means on the basis of the magnification and the height of the document. - View Dependent Claims (4, 6, 7, 10)
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2. A picture processing apparatus comprising:
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first edge detection means for detecting an edge of a document image from a picture obtained by imaging the document; skew detection means for detecting a skew of the document from the edge detected by the first edge detection means; picture reshaping means for reshaping a predetermined region of the picture on the basis of the skew; second edge detection means for detecting an edge of the document image from the picture reshaped by the picture reshaping means; magnification calculation means for calculating a magnification of the picture from the edge detected by the second edge detection means; height calculation means for calculating a height of the document from a reference plane on the basis of the edge detected by the second edge detection means; and distortion correction means for correcting a distortion of the picture through a magnification/reduction of the picture reshaped by the picture reshaping means on the basis of the magnification and the height of the document. - View Dependent Claims (8)
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3. A picture processing apparatus comprising:
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edge detection means for detecting an edge of a document image from a picture obtained by imaging the document; skew detection means for detecting a skew of the document from the edge; magnification calculation means for calculating a magnification of the picture from the edge; height calculation means for calculating a height of the document from a reference plane on the basis of the edge; distortion correction means for correcting a distortion of the picture by subdividing a predetermined region of the picture into a plurality of trapezoidal segments on the basis of the skew to individually perform magnification/reduction for each trapezoidal segment on the basis of the skew, magnification, and height of the document. - View Dependent Claims (5, 9)
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Specification