Sphere¶

class Sphere(*args, **kwargs)¶

Bases: ForwardProjection

Class that defines a 3D sphere in the object frame and allows forward projection of a 3D sphere in the camera frame and in the 2D image plane by perspective projection. All the parameters must be set in meter.

A sphere has the followings parameters:

in the object frame : the 3D coordinates oX, oY, oZ of the center and radius R. These parameters registered in vpForwardProjection::oP internal 4-dim vector are set using the constructors vpSphere (double oX, double oY, double oZ, double R), vpSphere(const vpColVector &oP) or the functions setWorldCoordinates(double oX, double oY, double oZ, double R) and setWorldCoordinates(const vpColVector &oP) . To get theses parameters use get_oP() .
in the camera frame : the coordinates cX, cY, cZ of the center and radius R. These parameters registered in vpTracker::cP internal 4-dim vector are computed using changeFrame(const vpHomogeneousMatrix &cMo, vpColVector &cP) const or changeFrame(const vpHomogeneousMatrix &cMo) . These parameters could be retrieved using getX() , getY() , getZ() and getR() . To get theses parameters use get_cP() .
in the image plane : here we consider the parameters of the ellipse corresponding to the perspective projection of the 3D sphere. The parameters are the ellipse centroid (x, y) and n20, n11, n02 which are the second order centered moments of the ellipse normalized by its area (i.e., such that \(n_{ij} = \mu_{ij}/a\) where \(\mu_{ij}\) are the centered moments and a the area). These parameters are registered in vpTracker::p internal 5-dim vector and computed using projection() and projection(const vpColVector &cP, vpColVector &p) const . They could be retrieved using get_x() , get_y() , get_n20() , get_n11() and get_n02() . They correspond to 2D normalized sphere parameters with values expressed in meters. To get theses parameters use get_p() .

Overloaded function.

__init__(self: visp._visp.core.Sphere) -> None

Default constructor.

__init__(self: visp._visp.core.Sphere, oP: visp._visp.core.ColVector) -> None

Create a sphere from a 4-dim vector that contains 3D coordinates of its center and its radius. The 3D coordinates of the center are defined in the sphere frame.

__init__(self: visp._visp.core.Sphere, oX: float, oY: float, oZ: float, R: float) -> None

Create a sphere from the 3D coordinates of its center and its radius. The 3D coordinates of the center are defined in the sphere frame.

Parameters:

oX: 3D coordinate of the sphere center along X axis in [m].
oY: 3D coordinate of the sphere center along X axis in [m].
oZ: 3D coordinate of the sphere center along X axis in [m].
R: Sphere radius in [m].

Methods

`__init__`	Overloaded function.
`changeFrame`	Overloaded function.
`display`	Overloaded function.
`getR`
`getX`
`getY`
`getZ`
`get_n02`
`get_n11`
`get_n20`
`get_x`
`get_y`
`projection`	Overloaded function.
`setWorldCoordinates`	Overloaded function.

Inherited Methods

`get_p`	Return object parameters expressed in the 2D image plane computed by perspective projection.
`user`
`vpDisplayForwardProjection`
`get_cP`	Return object parameters expressed in the 3D camera frame.
`getDeallocate`
`cP`
`track`	Track the feature parameters in the camera frame ( vpTracker::cP ) and than compute the projection of these parameters in the image plane ( vpTracker::p ).
`get_oP`	Return object parameters expressed in the 3D object frame.
`setDeallocate`
`p`
`project`	Overloaded function.
`cPAvailable`
`ForwardProjectionDeallocatorType`	Used for memory issue especially in the vpServo class.
`print`	Print to stdout the feature parameters in:
`oP`

Operators

`__doc__`
`__init__`	Overloaded function.
`__module__`

Attributes

`__annotations__`
`cP`
`cPAvailable`
`oP`
`p`
`user`
`vpDisplayForwardProjection`

class ForwardProjectionDeallocatorType(self, value: int)¶

Bases: pybind11_object

Used for memory issue especially in the vpServo class.

Values:

user
vpDisplayForwardProjection

__and__(self, other: object) → object¶

__eq__(self, other: object) → bool¶

__ge__(self, other: object) → bool¶

__getstate__(self) → int¶

__gt__(self, other: object) → bool¶

__hash__(self) → int¶

__index__(self) → int¶

__init__(self, value: int)¶

__int__(self) → int¶

__invert__(self) → object¶

__le__(self, other: object) → bool¶

__lt__(self, other: object) → bool¶

__ne__(self, other: object) → bool¶

__or__(self, other: object) → object¶

__rand__(self, other: object) → object¶

__ror__(self, other: object) → object¶

__rxor__(self, other: object) → object¶

__setstate__(self, state: int) → None¶

__xor__(self, other: object) → object¶

property name : str¶

__init__(*args, **kwargs)¶

Overloaded function.

__init__(self: visp._visp.core.Sphere) -> None

Default constructor.

__init__(self: visp._visp.core.Sphere, oP: visp._visp.core.ColVector) -> None

Create a sphere from a 4-dim vector that contains 3D coordinates of its center and its radius. The 3D coordinates of the center are defined in the sphere frame.

__init__(self: visp._visp.core.Sphere, oX: float, oY: float, oZ: float, R: float) -> None

Create a sphere from the 3D coordinates of its center and its radius. The 3D coordinates of the center are defined in the sphere frame.

Parameters:

oX: 3D coordinate of the sphere center along X axis in [m].
oY: 3D coordinate of the sphere center along X axis in [m].
oZ: 3D coordinate of the sphere center along X axis in [m].
R: Sphere radius in [m].

changeFrame(*args, **kwargs)¶

Overloaded function.

changeFrame(self: visp._visp.core.Sphere, cMo: visp._visp.core.HomogeneousMatrix, cP: visp._visp.core.ColVector) -> None

Perspective projection of the sphere. This method doesn’t modify internal sphere parameters cP.

Parameters:

cMo: Homogeneous transformation from camera frame to sphere frame.

changeFrame(self: visp._visp.core.Sphere, cMo: visp._visp.core.HomogeneousMatrix) -> None

Perspective projection of the sphere. Internal sphere parameters are modified in cP.

Parameters:

cMo: Homogeneous transformation from camera frame to object frame.

display(*args, **kwargs)¶

Overloaded function.

display(self: visp._visp.core.Sphere, I: visp._visp.core.ImageGray, cam: visp._visp.core.CameraParameters, color: visp._visp.core.Color = vpColor::green, thickness: int = 1) -> None

Display the projection of a 3D sphere in image I .

Parameters:

I: Image used as background.
cam: Camera parameters.
color: Color used to draw the sphere.
thickness: Thickness used to draw the sphere.

display(self: visp._visp.core.Sphere, I: visp._visp.core.ImageGray, cMo: visp._visp.core.HomogeneousMatrix, cam: visp._visp.core.CameraParameters, color: visp._visp.core.Color = vpColor::green, thickness: int = 1) -> None

Display the projection of a 3D sphere in image I . This method is non destructive wrt. cP and p internal sphere parameters.

Parameters:

I: Image used as background.
cMo: Homogeneous transformation from camera frame to object frame. The sphere is considered as viewed from this camera position.
cam: Camera parameters.
color: Color used to draw the sphere.
thickness: Thickness used to draw the sphere.

display(self: visp._visp.core.Sphere, I: visp._visp.core.ImageRGBa, cam: visp._visp.core.CameraParameters, color: visp._visp.core.Color = vpColor::green, thickness: int = 1) -> None

Display the projection of a 3D sphere in image I .

Parameters:

I: Image used as background.
cam: Camera parameters.
color: Color used to draw the sphere.
thickness: Thickness used to draw the sphere.

display(self: visp._visp.core.Sphere, I: visp._visp.core.ImageRGBa, cMo: visp._visp.core.HomogeneousMatrix, cam: visp._visp.core.CameraParameters, color: visp._visp.core.Color = vpColor::green, thickness: int = 1) -> None

Display the projection of a 3D sphere in image I . This method is non destructive wrt. cP and p internal sphere parameters.

Parameters:

I: Image used as background.
cMo: Homogeneous transformation from camera frame to object frame. The sphere is considered as viewed from this camera position.
cam: Camera parameters.
color: Color used to draw the sphere.
thickness: Thickness used to draw the sphere.

getDeallocate(self) → visp._visp.core.ForwardProjection.ForwardProjectionDeallocatorType¶

getR(self) → float¶

getX(self) → float¶

getY(self) → float¶

getZ(self) → float¶

get_cP(self) → visp._visp.core.ColVector¶: Return object parameters expressed in the 3D camera frame.

get_n02(self) → float¶

get_n11(self) → float¶

get_n20(self) → float¶

get_oP(self) → visp._visp.core.ColVector¶: Return object parameters expressed in the 3D object frame.

get_p(self) → visp._visp.core.ColVector¶: Return object parameters expressed in the 2D image plane computed by perspective projection.

get_x(self) → float¶

get_y(self) → float¶

print(self) → None¶

Print to stdout the feature parameters in:

the object frame
the camera frame
the image plane.

project(*args, **kwargs)¶

Overloaded function.

project(self: visp._visp.core.ForwardProjection) -> None

Compute the feature parameters in the image plane ( vpTracker::p ) from the parameters in the camera frame ( vpTracker::cP ).

Warning

Be careful to update vpTracker::p and vpTracker::cP public attributes before the call of this method.

project(self: visp._visp.core.ForwardProjection, cMo: visp._visp.core.HomogeneousMatrix) -> None

Compute the feature parameters in the camera frame ( vpTracker::cP ) and than compute the projection of these parameters in the image plane ( vpTracker::p ).

Warning

The feature parameters in the object frame ( vpForwardProjection :oP) need to be set prior the use of this method. To initialize these parameters see setWorldCoordinates() .

Parameters:

cMo: The homogeneous matrix corresponding to the pose between the camera frame and the object frame.

projection(*args, **kwargs)¶

Overloaded function.

projection(self: visp._visp.core.Sphere) -> None

Perspective projection of the sphere. This method updates internal parameters (cP and p).

See vpSphere::projection(const vpColVector &, vpColVector &) const for a more detailed description of the parameters.

projection(self: visp._visp.core.Sphere, cP: visp._visp.core.ColVector, p: visp._visp.core.ColVector) -> None

Perspective projection of the sphere. Internal parameters (cP and p) are not modified.

setDeallocate(self, d: visp._visp.core.ForwardProjection.ForwardProjectionDeallocatorType) → None¶

setWorldCoordinates(*args, **kwargs)¶

Overloaded function.

setWorldCoordinates(self: visp._visp.core.Sphere, oP: visp._visp.core.ColVector) -> None

Set sphere 3D parameters from a 4-dim vector that contains 3D coordinates of its center and its radius. The 3D coordinates of the center are defined in the sphere frame.

setWorldCoordinates(self: visp._visp.core.Sphere, oX: float, oY: float, oZ: float, R: float) -> None

Set sphere 3D parameters from the 3D coordinates of its center and its radius. The 3D coordinates of the center are defined in the sphere frame.

Parameters:

oX: 3D coordinate of the sphere center along X axis in [m].
oY: 3D coordinate of the sphere center along X axis in [m].
oZ: 3D coordinate of the sphere center along X axis in [m].
R: Sphere radius in [m].

track(self, cMo: visp._visp.core.HomogeneousMatrix) → None¶

Track the feature parameters in the camera frame ( vpTracker::cP ) and than compute the projection of these parameters in the image plane ( vpTracker::p ).

This method is similar to project(const vpHomogeneousMatrix &) .

Warning

The feature parameters in the object frame ( vpForwardProjection :oP) need to be set prior the use of this method. To initialize these parameters see setWorldCoordinates() .

Parameters:

cMo: visp._visp.core.HomogeneousMatrix¶: The homogeneous matrix corresponding to the pose between the camera frame and the object frame.