cameraIntrinsics
Object for storing intrinsic camera parameters
Description
Store information about a camera’s intrinsic calibration parameters, including the lens distortion parameters.
Creation
Syntax
Description
returns a camera intrinsics object that contains the focal length specified as
[fx,fy], and the camera's principal point
specified as [cx, cy]. See intrinsics
= cameraIntrinsics(focalLength
,principalPoint
,imageSize
)cameraParameters
for more details.
uses additional options specified by one or name-value pairs. Enclose each property name
in quotes. For example, intrinsics
= cameraIntrinsics(___,Name,Value
)intrinsics =
cameraIntrinsics('RadialDistortion',[0,0])
Input Arguments
focalLength
— Camera focal length
two-element vector
Camera focal length, specified as a two-element vector, [fx, fy].
F is the focal length in world units, typically millimeters
[sx, sy] are the number of pixels per world unit in the x and y direction respectively
fx and fy are in pixels
principalPoint
— Optical center of camera
two-element vector
Optical center of camera, specified as a two-element vector, [cx,cy], in pixels.
imageSize
— Image size produced by the camera
two-element vector
Image size produced by the camera, specified as a two-element vector, [mrows,ncols].
Properties
RadialDistortion
— Radial lens distortion
[0,0]
(default) | two-element vector | three-element vector
Radial lens distortion, specified as the comma-separated pair consisting of
RadialDistortion
and a two-element vector,
[k1,k2], or a three-element vector,
[k1,k2,k3].
k1,k2, and k3 are radial
distortion coefficients.
Radial distortion is the displacement of image points along radial lines extending from the principal point.
As image points move away from the principal point (positive radial displacement), image magnification decreases and a pincushion-shaped distortion occurs on the image.
As image points move toward the principal point (negative radial displacement), image magnification increases and a barrel-shaped distortion occurs on the image.
The camera parameters object calculates the radial distorted location of a point. You can denote the distorted points as (xdistorted, ydistorted), as follows:
xdistorted = x(1 + k1*r2 + k2*r4 + k3*r6) | (1) |
ydistorted= y(1 + k1*r2 + k2*r4 + k3*r6) | (2) |
x, y = undistorted pixel locations |
k1, k2, and k3 = radial distortion coefficients of the lens |
r2 = x2 + y2 |
TangentialDistortion
— Tangential distortion coefficients
[0,0]
(default) | two-element vector
Tangential distortion coefficients, specified as the comma-separated pair consisting
of 'TangentialDistortion
' and a 2-element vector,
[p1,p2].
Tangential distortion occurs when the lens and the image plane are not parallel.
The camera parameters object calculates the tangential distorted location of a point. You can denote the distorted points as (xdistorted, ydistorted), as follows:
xdistorted = x + [2 * p1 * x * y + p2 * (r2 + 2 * x2)] | (3) |
ydistorted = y + [p1 * (r2 + 2*y2) + 2 * p2 * x * y] | (4) |
x, y = undistorted pixel locations |
p1 and p2 = tangential distortion coefficients of the lens |
r2 = x2 + y2 |
Skew
— Camera axes skew
0
(default) | angle
Camera axes skew, specified as the comma-separated pair consisting of
'skew
' and an angle. If the x and the
y axes are exactly perpendicular, then the skew must be
0
.
FocalLength
— Focal length
2-element vector
This property is read-only.
Focal length in x and y, stored as a 2-element vector [fx, fy] in pixels.
fx = F * sx |
fy = F * sy |
The focal length F influences the angle of view and thus affects the area of the scene that appears focused in an image. For a fixed subject distance:
A short focal length offers a wide angle of view allowing to capture large area of the scene under focus. It emphasizes both the subject and the scene background.
A long focal length offers a narrow angle of view, thus reducing the area of the scene under focus. It emphasizes more on the subject and restricts the amount of background from being captured.
PrincipalPoint
— Optical center of camera
two-element vector
This property is read-only.
Optical center of camera, stored as a two-element vector [cx,cy] in pixels. The vector contains the coordinates of the optical center of the camera.
ImageSize
— Image size produced by the camera
two-element vector
This property is read-only.
Image size produced by the camera, stored as a two-element vector, [mrows,ncols].
IntrinsicMatrix
— Projection matrix
3-by-3 identity matrix (default) | 3-by-3 intrinsic matrix
This property is read-only.
Projection matrix, stored as the comma-separated pair consisting of
'IntrinsicMatrix
' and a 3-by-3 matrix. For the matrix format, the
object uses the following format:
The coordinates [cx
cy] represent the optical center (the
principal point), in pixels. When the x and y axis
are exactly perpendicular, the skew parameter, s, equals
0
.
fx = F*sx |
fy = F*sy |
F, is the focal length in world units, typically expressed in millimeters. |
[sx, sy] are the number of pixels per world unit in the x and y direction respectively. |
fx and fy are expressed in pixels. |
Examples
Create an Object Containing Fundamental Camera Parameters
Define camera parameters without lens distortion or skew.
Specify the focal length and principal point in pixels.
focalLength = [800, 800]; principalPoint = [320, 240]; imageSize = [480, 640];
Create a camera intrinsics object.
intrinsics = cameraIntrinsics(focalLength,principalPoint,imageSize)
intrinsics = cameraIntrinsics with properties: FocalLength: [800 800] PrincipalPoint: [320 240] ImageSize: [480 640] RadialDistortion: [0 0] TangentialDistortion: [0 0] Skew: 0 IntrinsicMatrix: [3x3 double]
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Version History
MATLAB 명령
다음 MATLAB 명령에 해당하는 링크를 클릭했습니다.
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