FeatureMomentCentered¶

class FeatureMomentCentered¶

Bases: FeatureMoment

Functionality computation for centered moment feature. Computes the interaction matrix associated with vpMomentCentered .

The interaction matrix for the feature is defined in [40] , equation (17). This vpFeatureMoment , as well as it’s corresponding moment primitive is double-indexed. The interaction matrix \(L_{\mu_{ij}}\) is obtained by calling vpFeatureMomentBasic::interaction (i,j) and is associated to \(\mu_{ij}\) obtained by vpFeatureMomentCentered::get (i,j).

vpFeatureMomentCentered computes interaction matrices all interaction matrices up to vpMomentObject::getOrder() -1.

Warning

The maximum order reached by vpFeatureMomentBasic is NOT the maximum order of the vpMomentObject , it is one unit smaller. For example if you define your vpMomentObject up to order n then vpFeatureMomentBasic will be able to compute interaction matrices up to order n-1 that is \(L_{m_{ij}}\) with \(i+j<=n-1\) .

This feature depends on:

vpFeatureMomentBasic
vpFeatureMomentGravityCenter
vpMomentGravityCenter

Methods

`__init__`
`compute_interaction`	Overloaded function.
`interaction`	Overloaded function.
`momentName`	Associated moment name
`name`	Feature name

Inherited Methods

`user`
`BasicFeatureSelect`	Indicates who should deallocate the feature.
`error`	Compute the error between two visual features from a subset of the possible features.
`setFlags`	Set feature flags to true to prevent warning when re-computing the interaction matrix without having updated the feature.
`FEATURE_ALL`
`getDimension`	Overloaded function.
`linkTo`	Links the feature to the feature's database.
`getDeallocate`
`init`	Initialize common parameters for moment features.
`dimension_s`	Return the dimension of the feature vector \(\bf s\) .
`setDeallocate`
`selectAll`	Select all the features.
`printDependencies`	Interface function to display the moments and other interaction matrices on which a particular vpFeatureMoment is dependent upon Not made pure to maintain compatibility Recommended : Types inheriting from vpFeatureMoment should implement this function.
`display`	Overloaded function.
`update`	Updates the interaction matrices with the image plane the camera is facing.
`get_s`	Get the feature vector \(\bf s\) .
`BasicFeatureDeallocatorType`	Indicates who should deallocate the feature.
`vpServo`
`print`	Outputs the content of the feature: it's corresponding selected moments.

Operators

`__doc__`
`__init__`
`__module__`
`__repr__`

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__(*args, **kwargs)¶

compute_interaction(*args, **kwargs)¶

Overloaded function.

compute_interaction(self: visp._visp.visual_features.FeatureMomentCentered) -> None

Interface to the interaction matrix computation for centered moments. Called internally. Calls compute_Lmu_pq() for main computation moments (upto order-1)

Dependencies to moment classes:

vpMomentBasic

Dependencies to interaction matrix classes:

vpMomentGravityCenter
vpFeatureMomentBasic
vpFeatureMomentGravityCenter

compute_interaction(self: visp._visp.visual_features.FeatureMoment) -> None

dimension_s(self) → int¶: Return the dimension of the feature vector \(\bf s\) .

display(*args, **kwargs)¶

Overloaded function.

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

Not implemented since visual representation of a moment doesn’t often make sense.

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

Not implemented since visual representation of a moment doesn’t often make sense.

error(self, 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.

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

getDimension(*args, **kwargs)¶

Overloaded function.

getDimension(self: visp._visp.visual_features.FeatureMoment, select: int = FEATURE_ALL) -> int

Feature’s dimension according to selection.

getDimension(self: visp._visp.visual_features.BasicFeature, select: int = FEATURE_ALL) -> int

Get the feature vector dimension.

get_s(self, select: int = FEATURE_ALL) → visp._visp.core.ColVector¶: Get the feature vector \(\bf s\) .

init(self) → None¶: Initialize common parameters for moment features.

interaction(*args, **kwargs)¶

Overloaded function.

interaction(self: visp._visp.visual_features.FeatureMomentCentered, select_one: int, select_two: int) -> visp._visp.core.Matrix

Parameters:

select_one: first index (i).
select_two: second index (j).

Returns:

Interaction matrix corresponding to the moment.

interaction(self: visp._visp.visual_features.FeatureMoment, select: int = FEATURE_ALL) -> visp._visp.core.Matrix

Retrieves the interaction matrix. No computation is done.

There is no rule about the format of the feature selector. It may be different for different features. For example, for vpFeatureMomentBasic or vpFeatureMomentCentered features, select may refer to the \((i,j)\) couple in the \(j \times order + i\) format, but for vpFeatureMomentCInvariant the selector allows to select couples \((i,j,k,l...)\) in the following format: 1 << i

1 << j + 1 << k + 1 << l.

Parameters:

select: Feature selector.

Returns:

The corresponding interaction matrix.

linkTo(self, featureMoments: visp._visp.visual_features.FeatureMomentDatabase) → None¶

Links the feature to the feature’s database.

Note

The feature’s database is different from the moment’s database.

Parameters:

featureMoments: visp._visp.visual_features.FeatureMomentDatabase¶: database in which the moment features are stored.

momentName(self) → str¶: Associated moment name

name(self) → str¶: Feature name

print(self, select: int = FEATURE_ALL) → None¶: Outputs the content of the feature: it’s corresponding selected moments.

printDependencies(self: visp._visp.visual_features.FeatureMoment, os: std::ostream) → None¶: Interface function to display the moments and other interaction matrices on which a particular vpFeatureMoment is dependent upon Not made pure to maintain compatibility Recommended : Types inheriting from vpFeatureMoment should implement this function.

static selectAll() → int¶: Select all the features.

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.

update(self, A: float, B: float, C: float) → None¶

Updates the interaction matrices with the image plane the camera is facing. The plane must be in the format: \(\frac{1}{Z}=Ax+By+C\) . The moment primitives MUST be updated before calling this function.

This method also computes the interaction matrix. Therefore, you must call vpFeatureMoment::update before calling vpFeatureMoment::interaction .

Warning

The behaviour of this method is not the same as vpMoment::update which only acknowledges the new object. This method also computes the interaction matrices.