Image processing device and image processing method

• US 7,545,993 B2
• Filed: 12/28/2005
• Issued: 06/09/2009
• Est. Priority Date: 07/04/2005
• Status: Expired due to Fees

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Matsuda, Yoichi, Yamashita, Shigeki
• Primary Examiner(s): PATEL, KANJIBHAI B
• Application Number:
  US11/318,541
• Publication Number:
  US 20070003159A1
• Time in Patent Office: 1,259 Days
• Field of Search: 382/260, 382/261, 382/274, 382/275, 382/289, 382/291, 382/294, 382/295, 382/298, 382/305, 382/3.26, 382/528, 382/312, 382/1.2, 358/1.2, 358/3.26, 358/528, 345/660, 345/662, 348/240.99
• US Class Current: 382/275
• CPC Class Codes: G06T 5/80 Geometric correction
• CPC Class Codes: G06T 5/92 based on global image properties

Abstract

An image processing device for correcting a deformation of a photographic image of an object to be photographed, the deformation resulting from a photographic position of the object, comprises an inputting unit that inputs the photographic image; an image correcting unit that corrects a deformation of the photographic image inputted by the inputting to produce a corrected image; and an image processing unit that performs different image processings that are different from each other for the corrected image corrected by the image correcting unit, the different image processings being performed in different manners in accordance with correction amount by the image correcting unit.

Claims

1. An image processing device for correcting a deformation of a deformed photographic image of an object photographed by a camera, the deformation resulting from a photographic position of the object with respect to the camera, the device comprising:

an inputting unit that inputs the deformed photographic image;

an image correcting unit that corrects the deformation of the deformed photographic image to produce a corrected image; and

an image processing unit that performs different image processing operations that are different from each other for the corrected image, the different image processing operations being performed in different manners in accordance with an amount of correction the image correcting unit makes to the deformed photographic image,

wherein the deformation results from different angles of incidence of light, from different points of the object, onto the camera.

2. The image processing device according to claim 1, wherein the image correcting unit comprises:

a magnification determining unit that respectively determines magnifications in prescribed directions of image data corresponding to the photographic image; and

a magnification processing unit that performs magnification processing of the image data in the prescribed directions using the magnifications determined by the magnification determining unit,

wherein the image processing unit performs respectively different image processing operations for the image data that has been subjected to the magnification processing performed by the magnification processing unit in accordance with the magnifications of the magnification processing.

3. The image processing device according to claim 2, wherein

the object to be photographed is a square, and

the magnification determining unit comprises:

a scanning unit that sequentially scans the image data along lines parallel to a prescribed side of the square of the image data;

an inputting unit that inputs coordinates of vertexes of a square of the object before the correction; and

a determining unit that determines vertexes of the square after the correction from the coordinates of the vertexes inputted by the inputting unit, and determines the magnifications for each scan line.

4. The image processing device according to claim 1, wherein the image processing unit performs the different image processing operations by digital filtering processes with different filter coefficients.

5. The image processing device according to claim 1, wherein the image processing unit performs the different image processing operations by digital filtering processes with different filter sizes.

6. The image processing device according to claim 1, wherein the image processing unit performs the different image processing operations by contrast processes with different look-up tables.

7. An image processing method for correcting a deformation in a deformed photographic image of an object photographed by a camera, resulting from a photographic position of the object with respect to the camera, the method comprising:

inputting the deformed photographic image by an inputting unit;

correcting, by an image correcting unit, the deformation of the deformed photographic image to produce a corrected image; and

performing, by an image processing unit, image processing operations, which differs from each other in accordance with an amount of correction the image correcting unit makes to the deformed photographic image, for the corrected image

wherein the deformation results from different angles of incidence of light, from different points of the object, onto the camera.

8. The method of claim 7, wherein the different angles of incidence result from a non-zero angle between the camera and a surface of the object.

9. The method of claim 7,

wherein the photographic image is of a rectangle, and

wherein the deformed photographic image is a trapezoid.

10. The method of claim 9, wherein the inputting the deformed photographic image includes:

receiving coordinates of four corners of the trapezoid;

setting one of the four corners as an origin of a coordinate system having a first axis and a second axis perpendicular to the first axis;

setting a first line through the origin and parallel to two parallel sides of the trapezoid as the first axis;

setting a second line through the origin as the second axis;

determining coordinates of the four corners of the trapezoid as a first coordinate (0,0), a second coordinate (0,xt), a third coordinate (xa,yt) and a fourth coordinate (xb,yt), where xt is longest of the coordinates along the first axis and yt is longest of the coordinates along the second axis; and

deducing from the coordinates of the four corners of the trapezoid, rectangle coordinates of four corners of the rectangle as (0,0), (xt,0), (0,yt), and (xt,yt) by treating the first coordinate (0,0) and a point (xt,yt) as corners of the rectangle.

11. The method of claim 10, wherein the correcting of the deformation of the rectangle includes:

modifying a width Bn of the trapezoid at yn to arrive at a rectangle width Wn parallel to the first axis at yn, the width Bn of the trapezoid being a width parallel to the first axis at the distance yn from the origin, 0≦

yn≦

yt, by determining a correction factor Ln from a relationship as follows;

Wn=Bn*Ln, where;

Ln=xt/Bn,

Bn=xt−

An−

Cn,

An=xa*yn/yt, and

Cn=(xt−

xb)*yn/yt, and

wherein the amount of correction is a function of the correction factor Ln.

12. The method of claim 11, wherein the performing of the image processing includes:

applying a filter to the corrected image; and

varying a filter type of the filter according to the correction factor Ln.