Image processing apparatus for correcting distortion of image and image shooting apparatus for correcting distortion of shot image
First Claim
1. An image processing apparatus which corrects distortion of an image, and comprises:
- a shot-image acquisition section which acquires a shot image of a subject to be shot, including a shooting target image which is an image portion corresponding to said subject to be shot, wherein a real shape of said subject to be shot is a rectangle;
a reduced-image acquisition section which acquires a reduced image that is said shot image with a reduced resolution;
a distortion information acquisition section which acquires a corrected reduced image by performing distortion correction on said reduced image according to a characteristic of a lens used in shooting, acquires a contour of said shooting target image based on said corrected reduced image, specifies four line portions of said contour, and acquires a shape of a trapezoid formed by said four line portions as distortion information;
a projection parameter acquisition section which acquires a projection parameter for converting said shooting target image to an ideal distortion-free image based on said distortion information; and
a projection transformation section which produces a projection-transformed image by performing projection transformation on said shot image using said projection parameter.
1 Assignment
0 Petitions
Accused Products
Abstract
A digital camera acquires the image of an original including an original from a shot image acquired by shooting. The digital camera reduces the image of the original and corrects distortion of the reduced image which is originated from the characteristic of a lens. As the digital camera performs distortion correction on the reduced image, the number of arithmetic operations in distortion correction is reduced, making distortion correction simpler. The digital camera acquires a rectangle defined by the contour of the original, extracts the image of the original to acquire an original image before reduction, and acquires an associated projection-transformed image by affine transformation. The digital camera acquires pixel positions of the original image using an affine parameter, and acquires pixel positions of the image before distortion correction using a relational expression of distortion correction performed on the reduced image.
35 Citations
15 Claims
-
1. An image processing apparatus which corrects distortion of an image, and comprises:
-
a shot-image acquisition section which acquires a shot image of a subject to be shot, including a shooting target image which is an image portion corresponding to said subject to be shot, wherein a real shape of said subject to be shot is a rectangle; a reduced-image acquisition section which acquires a reduced image that is said shot image with a reduced resolution; a distortion information acquisition section which acquires a corrected reduced image by performing distortion correction on said reduced image according to a characteristic of a lens used in shooting, acquires a contour of said shooting target image based on said corrected reduced image, specifies four line portions of said contour, and acquires a shape of a trapezoid formed by said four line portions as distortion information; a projection parameter acquisition section which acquires a projection parameter for converting said shooting target image to an ideal distortion-free image based on said distortion information; and a projection transformation section which produces a projection-transformed image by performing projection transformation on said shot image using said projection parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An image processing apparatus which corrects distortion of an image, comprising:
-
a shot-image acquisition section which acquires a shot image of a subject to be shot, including a shooting target image which is an image portion corresponding to said subject to be shot; a reduced-image acquisition section which acquires a reduced image that is said shot image with a reduced resolution; a distortion information acquisition section which acquires a corrected reduced image by performing distortion correction on said reduced image according to a characteristic of a lens used in shooting, and acquires distortion information indicative of linear distortion of said shooting target image based on said corrected reduced image; a projection parameter acquisition section which acquires a projection parameter for converting said shooting target image to an ideal distortion-free image based on said distortion information; and a projection transformation section which produces a projection-transformed image by performing distortion correction according to said characteristic of said lens concurrently with performing projection transformation on said shot image using said projection parameter.
-
-
10. An image shooting apparatus which corrects distortion of a shot image, comprising:
-
a lens having a predetermined characteristic; an image pickup section which shoots a subject to be shot through said lens, thereby acquiring a shot image, wherein a real shape of said subject to be shot is a rectangle; a corrected reduced-image acquisition section which acquires a corrected reduced image by reducing a resolution of said shot image and performing distortion correction according to said characteristic of said lens; a distortion information acquisition section which acquires a contour of said shot subject based on said corrected reduced image, specifies four line portions of said contour, and acquires a shape of a trapezoid formed by said four line portions as distortion information; and a projection transformation section which converts said shot image to an ideal distortion-free image based on said distortion information. - View Dependent Claims (11, 12)
-
-
13. An image processing method comprising:
-
acquiring a shot image of a subject to be shot, including a shooting target image which is an image portion corresponding to said subject to be shot, wherein a real shape of said subject to be shot is a rectangle; acquiring a reduced image that is said shot image with a reduced resolution; acquiring a corrected reduced image by performing distortion correction on said reduced image according to a characteristic of a lens used in shooting; acquiring a contour of said shooting target image based on said corrected reduced image, specifying four line portions of said contour, and acquiring a shape of a trapezoid formed by said four line portions as distortion information; acquiring a projection parameter for converting said shooting target image to an ideal distortion-free image based on said distortion information; and producing a projection-transformed image by performing projection transformation on said shot image using said projection parameter.
-
-
14. A recording medium having a program stored thereon which is executable by an image processing apparatus to execute functions comprising:
-
acquiring a shot image of a subject to be shot, including a shooting target image which is an image portion corresponding to said subject to be shot, wherein a real shape of said subject to be shot is a rectangle; acquiring a reduced image that is said shot image with a reduced resolution; acquiring a corrected reduced image by performing distortion correction on said reduced image according to a characteristic of a lens used in shooting; acquiring a contour of said shooting target image based on said corrected reduced image, specifying four line portions of said contour, and acquiring a shape of a trapezoid formed by said four line portions as distortion information; acquiring a projection parameter for converting said shooting target image to an ideal distortion-free image based on said distortion information; and producing a projection transformed image by performing projection transformation on said shot image using said projection parameter.
-
-
15. A recording medium having a program stored thereon which is executable by an image processing apparatus to execute functions comprising:
-
acquiring a shot image of a subject to be shot, including a shooting target image which is an image portion corresponding to said subject to be shot; acquiring a reduced image that is said shot image with a reduced resolution; acquiring a corrected reduced image by performing distortion correction on said reduced image according to a characteristic of a lens used in shooting; acquiring distortion information indicative of linear distortion of said shooting target image based on said reduced image; acquiring a projection parameter for converting said shooting target image to an ideal distortion-free image based on said distortion information; and producing a projection-transformed image by performing distortion correction according to said characteristic of said lens concurrently with performing projection transformation on said shot image using said projection parameter.
-
Specification