FeatureVanishingPoint¶

class FeatureVanishingPoint(self)¶

Bases: BasicFeature

Class that defines 2D vanishing point visual features. Various features can be considered:

• Either the cartesian coordinates \((x, y)\) of the vanishing point obtained from the intersection of two lines; in that case \({\bf s} = (x, y)\) and the corresponding interaction matrices are:

  \[L_x = \left[ \begin{array}{cccccc} 0 & 0 & 0 & x y & -(1 + x^2) & y \end{array} \right] \]
  \[L_y = \left[ \begin{array}{cccccc} 0 & 0 & 0 & 1 + y * y & -xy & -x \end{array} \right] \]

• Rather features function of the polar coordinates of the vanishing point obtained themselves from the polar coordinates of the two lines \((\rho_1, \theta_1)\) and \((\rho_2, \theta_2)\) ; in that case \({\bf s} = (\arctan(1/\rho), 1/\rho, \alpha)\) with:

  \[1/\rho = \frac{\sin(\theta_1 - \theta_2)}{\sqrt{\rho_1^2 + \rho_2^2 - 2 \rho_1 \rho_2 cos(\theta_1 - \theta_2)}} \]
  \[\alpha = \frac{\rho_1 \cos \theta_2 - \rho_2 cos \theta_1}{\sqrt{\rho_1^2 + \rho_2^2 - 2 \rho_1 \rho_2 cos(\theta_1 - \theta_2)}} \]

The corresponding interaction matrices are:

\[L_{\arctan(\frac{1}{\rho})} = \left[ \begin{array}{cccccc} 0 & 0 & 0 & - \sin \alpha & \cos \alpha & 0 \end{array} \right] \]

\[L_{\frac{1}{\rho}} = \left[ \begin{array}{cccccc} 0 & 0 & 0 & -(1 + \frac{1}{\rho^2}) \sin \alpha & (1 + \frac{1}{\rho^2}) \cos \alpha & 0 \end{array} \right] \]

\[L_{\alpha} = \left[ \begin{array}{cccccc} 0 & 0 & 0 & \frac{\cos \alpha}{\rho} & \frac{\sin \alpha}{\rho} & -1 \end{array} \right] \]

Default constructor that calls init() .

Methods

__init__	Default constructor that calls init() .
buildFrom	Set vanishing point visual feature \({\bf s} = (x, y)\) from cartesian coordinates.
display	Overloaded function.
error	Overloaded function.
getAlpha	Get vanishing point feature \(\alpha\) value.
getAtanOneOverRho	Get vanishing point feature \(\arctan(1/\rho)\) value.
getOneOverRho	Get vanishing point feature \(1/\rho\) value.
get_x	Get vanishing point feature \(x\) value.
get_y	Get vanishing point feature \(y\) value.
init	Vanishing point visual feature initialization.
interaction	Compute the interaction matrix from a subset of the possible features.
print	Print vanishing point features values to stdout.
selectAlpha	Select \(s = \theta\) visual feature.
selectAtanOneOverRho	Select visual feature \(s = \arctan(1/\rho)\) .
selectOneOverRho	Select visual feature \(s = 1/\rho\) .
selectX	Select visual feature \(s = x\) .
selectY	Select visual feature \(s = y\) .
setAlpha	Set vanishing point feature \(\alpha\) value.
setAtanOneOverRho	Set vanishing point feature \(\arctan(1/\rho)\) value.
setOneOverRho	Set vanishing point feature \(1/\rho\) value.
set_x	Set vanishing point feature \(x\) value.
set_xy	Set vanishing point visual feature \({\bf s} = (x, y)\) from cartesian coordinates.
set_y	Set vanishing point feature \(y\) value.

Inherited Methods

user
BasicFeatureSelect	Indicates who should deallocate the feature.
setFlags	Set feature flags to true to prevent warning when re-computing the interaction matrix without having updated the feature.
FEATURE_ALL
getDimension	Get the feature vector dimension.
getDeallocate
dimension_s	Return the dimension of the feature vector \(\bf s\) .
setDeallocate
selectAll	Select all the features.
get_s	Get the feature vector \(\bf s\) .
BasicFeatureDeallocatorType	Indicates who should deallocate the feature.
vpServo

Operators

__doc__
__init__	Default constructor that calls init() .
__module__

Attributes

FEATURE_ALL
__annotations__
user
vpServo

class BasicFeatureDeallocatorType(self, value: int)¶

Bases: pybind11_object

Indicates who should deallocate the feature.

Values:

• user

• vpServo

__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¶

class BasicFeatureSelect(self, value: int)¶

Bases: pybind11_object

Indicates who should deallocate the feature.

Values:

• user

• vpServo

__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__(self)¶

Default constructor that calls init() .

buildFrom(self, x: float, y: float) → None¶

Set vanishing point visual feature \({\bf s} = (x, y)\) from cartesian coordinates. Same as set_xy() .

dimension_s(self) → int¶

Return the dimension of the feature vector \(\bf s\) .

display(*args, **kwargs)¶

Overloaded function.

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

Display vanishing point feature.

Parameters:

cam

Camera parameters.

I

Image.

color

Color to use for the display.

thickness

Thickness of the feature representation.

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

Display vanishing point feature.

Parameters:

cam

Camera parameters.

I

color Image.

color

Color to use for the display.

thickness

Thickness of the feature representation.

error(*args, **kwargs)¶

Overloaded function.

1. error(self: visp._visp.visual_features.FeatureVanishingPoint, s_star: visp._visp.visual_features.BasicFeature, select: int = (vpFeatureVanishingPoint::selectX()|vpFeatureVanishingPoint::selectY())) -> visp._visp.core.ColVector

Compute the error between two visual features from a subset of the possible features.

Parameters:

s_star

Desired visual feature \({\bf s}^*\) .

select

Feature selector. Value is either selectX() to select x visual feature, selectY() for y visual feature, selectOneOverRho() for \(1/\rho\) , or selectAlpha() for \(\alpha\) visual feature. You can also use a combination like selectX() | selectY() to select x and y visual features.

2. error(self: visp._visp.visual_features.BasicFeature, s_star: visp._visp.visual_features.BasicFeature, select: int = FEATURE_ALL) -> visp._visp.core.ColVector

Compute the error between two visual features from a subset of the possible features.

getAlpha(self) → float¶

Get vanishing point feature \(\alpha\) value.

getAtanOneOverRho(self) → float¶

Get vanishing point feature \(\arctan(1/\rho)\) value.

getDeallocate(self) → visp._visp.visual_features.BasicFeature.BasicFeatureDeallocatorType¶

getDimension(self, select: int = FEATURE_ALL) → int¶

Get the feature vector dimension.

getOneOverRho(self) → float¶

Get vanishing point feature \(1/\rho\) value.

get_s(self, select: int = FEATURE_ALL) → visp._visp.core.ColVector¶

Get the feature vector \(\bf s\) .

get_x(self) → float¶

Get vanishing point feature \(x\) value.

get_y(self) → float¶

Get vanishing point feature \(y\) value.

init(self) → None¶

Vanishing point visual feature initialization.

interaction(self: visp._visp.visual_features.FeatureVanishingPoint, select: int = (vpFeatureVanishingPoint::selectX()|vpFeatureVanishingPoint::selectY())) → visp._visp.core.Matrix¶

Compute the interaction matrix from a subset of the possible features.

Parameters:

select

Feature selector. Value is either selectX() to select x visual feature, selectY() for y visual feature, selectOneOverRho() for \(1/\rho\) , or selectAlpha() for \(\alpha\) visual feature. You can also use a combination like selectX() | selectY() to select x and y visual features.

print(self: visp._visp.visual_features.FeatureVanishingPoint, select: int = (vpFeatureVanishingPoint::selectX()|vpFeatureVanishingPoint::selectY())) → None¶

Print vanishing point features values to stdout.

Parameters:

select

Use either selectX() to display x value, selectY() to display y value, select selectOneOverRho() to display \(1/\rho\) value, or selectAlpha() to display \(\alpha\) value. You can also use a combination like selectX() | selectY() to display x and y values.

static selectAll() → int¶

Select all the features.

static selectAlpha() → int¶

Select \(s = \theta\) visual feature.

static selectAtanOneOverRho() → int¶

Select visual feature \(s = \arctan(1/\rho)\) .

static selectOneOverRho() → int¶

Select visual feature \(s = 1/\rho\) .

static selectX() → int¶

Select visual feature \(s = x\) .

static selectY() → int¶

Select visual feature \(s = y\) .

setAlpha(self, alpha: float) → None¶

Set vanishing point feature \(\alpha\) value.

setAtanOneOverRho(self, atan_one_over_rho: float) → None¶

Set vanishing point feature \(\arctan(1/\rho)\) value.

setDeallocate(self, d: visp._visp.visual_features.BasicFeature.BasicFeatureDeallocatorType) → None¶

setFlags(self) → None¶

Set feature flags to true to prevent warning when re-computing the interaction matrix without having updated the feature.

setOneOverRho(self, one_over_rho: float) → None¶

Set vanishing point feature \(1/\rho\) value.

set_x(self, x: float) → None¶

Set vanishing point feature \(x\) value.

set_xy(self, x: float, y: float) → None¶

Set vanishing point visual feature \({\bf s} = (x, y)\) from cartesian coordinates. Same as buildFrom() .

set_y(self, y: float) → None¶

Set vanishing point feature \(y\) value.