IMAGE CONVERTER
First Claim
1. An image converter for performing processes of cutting out a part of a distorted circular image photographed by use of a fisheye lens and converting said part into a planar regular image, the image converter comprising:
- a distorted circular image memory for storing a distorted circular image constituted with an aggregate of many pixels arranged at a position indicated by coordinates (x, y) on a two-dimensional XY orthogonal coordinate system and having a radius R taking an origin O of the two-dimensional XY orthogonal coordinate system as a center;
a planar regular image memory for storing a planar regular image constituted with an aggregate of many pixels arranged at a position indicated by coordinates (u, v) on a two-dimensional UV orthogonal coordinate system;
a parameter input unit in which in a three-dimensional XYZ orthogonal coordinate system including the two-dimensional XY orthogonal coordinate system, a visual line vector n facing any given direction, with the origin O given as a starting point, is input as a parameter indicating a cut-out position of the planar regular image, a predetermined planar inclination angle φ
is input as a parameter indicating a cut-out orientation of the planar regular image, and a predetermined magnification m is input as a parameter indicating a cut-out dimension of the planar regular image;
a corresponding coordinate calculating unit calculating corresponding coordinates (x, y) which correspond to any given coordinates (u, v) by using predetermined correspondence relationship equations showing a correspondence relationship between coordinates (u, v) on a two-dimensional UV curved coordinate system and coordinates (x, y) on the two-dimensional XY orthogonal coordinate system, wherein said two-dimensional UV curved coordinate system is defined by curving a two-dimensional UV orthogonal coordinate system which is arranged on a plane passing through a point G given as an origin and orthogonal to the visual line vector n to have an orientation according to the planar inclination angle φ
, said point G being away from the origin O by “
a product m·
R of the magnification m and the radius R”
on the visual line vector n, along a side face of a “
virtual cylindrical column in which the point G gives one point on the side face thereof to have a central axis parallel to a V axis of the two-dimensional UV orthogonal coordinate system,”
; and
a planar regular image forming unit giving coordinates (u, v) of a target pixel constituting the planar regular image to the corresponding coordinate calculating unit to obtain corresponding coordinates (x, y), reading out a pixel value of a pixel arranged in the vicinity of the obtained corresponding coordinates (x, y) inside the distorted circular image memory, determining a pixel value of the target pixel on the basis of a read pixel value, thereby forming the planar regular image by determining pixel values of individual pixels, and writing the pixel values into the planar regular image memory.
1 Assignment
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Accused Products
Abstract
Any given part is cut out from a distorted circular image photographed by use of a fisheye lens and converted into a planar regular image with less distortion. A virtual sphere H having a radius R on a distorted circular image S on an XY plane is defined, thereby allowing a user to designate a cut-out center point P, a magnification m, and a planar inclination angle φ. A visual line vector n passing through an intersecting point Q immediately above the point P is determined to define an UV orthogonal coordinate system having an orientation depending on the angle φ on a plane orthogonal to a visual line vector n at a point G in which a distance between two points OG is given as m·R. The UV orthogonal coordinate system is curved along the side face C of a “virtual cylindrical column in which the point G forms one point on the side face to have a straight line V′ parallel to the V axis and also passing through the point O as a central axis,” thereby defining the UV curved coordinate system. Correspondence relationship equations between a point Ci (ui, vi) on the UV curved coordinate system and a point Si (xi, yi) on the XY coordinate system are used to obtain an image in the vicinity of a point P on the UV curved coordinate system, and the image is expanded on a plane T to obtain a planar regular image.
29 Citations
17 Claims
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1. An image converter for performing processes of cutting out a part of a distorted circular image photographed by use of a fisheye lens and converting said part into a planar regular image, the image converter comprising:
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a distorted circular image memory for storing a distorted circular image constituted with an aggregate of many pixels arranged at a position indicated by coordinates (x, y) on a two-dimensional XY orthogonal coordinate system and having a radius R taking an origin O of the two-dimensional XY orthogonal coordinate system as a center; a planar regular image memory for storing a planar regular image constituted with an aggregate of many pixels arranged at a position indicated by coordinates (u, v) on a two-dimensional UV orthogonal coordinate system; a parameter input unit in which in a three-dimensional XYZ orthogonal coordinate system including the two-dimensional XY orthogonal coordinate system, a visual line vector n facing any given direction, with the origin O given as a starting point, is input as a parameter indicating a cut-out position of the planar regular image, a predetermined planar inclination angle φ
is input as a parameter indicating a cut-out orientation of the planar regular image, and a predetermined magnification m is input as a parameter indicating a cut-out dimension of the planar regular image;a corresponding coordinate calculating unit calculating corresponding coordinates (x, y) which correspond to any given coordinates (u, v) by using predetermined correspondence relationship equations showing a correspondence relationship between coordinates (u, v) on a two-dimensional UV curved coordinate system and coordinates (x, y) on the two-dimensional XY orthogonal coordinate system, wherein said two-dimensional UV curved coordinate system is defined by curving a two-dimensional UV orthogonal coordinate system which is arranged on a plane passing through a point G given as an origin and orthogonal to the visual line vector n to have an orientation according to the planar inclination angle φ
, said point G being away from the origin O by “
a product m·
R of the magnification m and the radius R”
on the visual line vector n, along a side face of a “
virtual cylindrical column in which the point G gives one point on the side face thereof to have a central axis parallel to a V axis of the two-dimensional UV orthogonal coordinate system,”
; anda planar regular image forming unit giving coordinates (u, v) of a target pixel constituting the planar regular image to the corresponding coordinate calculating unit to obtain corresponding coordinates (x, y), reading out a pixel value of a pixel arranged in the vicinity of the obtained corresponding coordinates (x, y) inside the distorted circular image memory, determining a pixel value of the target pixel on the basis of a read pixel value, thereby forming the planar regular image by determining pixel values of individual pixels, and writing the pixel values into the planar regular image memory. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An image conversion method for performing processes of cutting out a part of a distorted circular image photographed by use of a fisheye lens and converting said part into a planar regular image, the image conversion method including:
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an image preparation step for storing in a distorted circular image memory a distorted circular image constituted with an aggregate of many pixels arranged at a position indicated by coordinates (x, y) on a two-dimensional XY orthogonal coordinate system and having a radius R taking an origin O of the two-dimensional XY orthogonal coordinate system as a center; a parameter setting step for setting in a three-dimensional XYZ orthogonal coordinate system including the two-dimensional XY orthogonal coordinate system, a visual line vector n which faces any given direction with the origin O given as a starting point, as a parameter indicating a cut-out position of a planar regular image, a predetermined planar inclination angle φ
as a parameter indicating a cut-out orientation of the planar regular image, and a predetermined magnification m as a parameter indicating a cut-out dimension of the planar regular image;a corresponding coordinate calculating step in which an operation device calculates corresponding coordinates (x, y) which correspond to coordinates (u, v) of one target pixel for a planar regular image made up of an aggregate of many pixels arranged at a positioned indicated by coordinates (u, v) on the two-dimensional UV orthogonal coordinate system; a pixel value determining step in which the operation device reads out a pixel value of a pixel arranged in the vicinity of the corresponding coordinates (x, y) inside the distorted circular image memory, determining a pixel value of the target pixel on the basis of a thus read pixel value; and a pixel value writing step in which the operation device writes a pixel value determined with regard to the target pixel inside a planar regular image memory for storing the planar regular image; wherein, in the corresponding coordinate calculating step, a point G on the visual line vector n spaced away from the origin O by “
a product m·
R of the magnification m and the radius R”
being given as an origin, a two-dimensional UV orthogonal coordinate system arranged to have an orientation depending on the planar inclination angle φ
on a plane passing through the point G and orthogonal to the visual line vector n is curved along a side face of “
a virtual cylindrical column in which the point G gives one point on the side face to have a central axis parallel to the V axis of the two-dimensional UV orthogonal coordinate system,”
thereby defining a two-dimensional UV curved coordinate system, and predetermined correspondence relationship equations indicating a correspondence relationship between coordinates (u, v) on the two-dimensional UV curved coordinate system and coordinates (x, y) on the two-dimensional XY orthogonal coordinate system are used to calculate corresponding coordinates (x, y) which correspond to any given coordinates (u, v), thereby writing pixel values for all pixels necessary for constituting the planar regular image into the planar regular image memory.
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17. An image conversion method including:
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a step for preparing a distorted circular image photographed by use of a fisheye lens as an aggregate of many pixels arranged at a position indicated by coordinates (x, y) on an XY plane in a three-dimensional XYZ orthogonal coordinate system; a step for defining, at a desired position inside a space constituting the three-dimensional XYZ orthogonal coordinate system, a two-dimensional UV curved coordinate system constituted with a V axis arranged on a curved face along a side face of a virtual cylindrical column and parallel to a central axis of the virtual cylindrical column and a circular-arc U axis along a circumference of a circle constituting a cross section obtained by cutting the virtual cylindrical column with a face orthogonal to the V axis; a step for obtaining a curved regular image constituted with an aggregate of many pixels on the two-dimensional UV curved coordinate system by using a correspondence relationship equation for allowing coordinates (u, v) on the two-dimensional UV curved coordinate system to correspond to corresponding coordinates (x, y) on the XY plane one by one to determine a pixel value of a pixel arranged at coordinates (u, v) on the two-dimensional UV curved coordinate system on the basis of a pixel value of a pixel arranged in the vicinity of the corresponding coordinates (x, y); and a step for converting the curved regular image into a planar regular image by expanding the two-dimensional UV curved coordinate system on a plane.
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Specification