boofcv.alg.feature.detect.interest

Class FeaturePyramid<T extends boofcv.struct.image.ImageGray,D extends boofcv.struct.image.ImageGray>

java.lang.Object

boofcv.alg.feature.detect.interest.FeaturePyramid<T,D>

All Implemented Interfaces:

InterestPointScaleSpacePyramid<T>

public class FeaturePyramid<T extends boofcv.struct.image.ImageGray,D extends boofcv.struct.image.ImageGray>
extends java.lang.Object
implements InterestPointScaleSpacePyramid<T>

Detects scale invariant interest/corner points by computing the feature intensities across a pyramid of different scales. Features which are maximums with in a local 2D neighborhood and within the local scale neighbourhood are declared to be features. Maximums are checked for in scale space by comparing the feature intensity against features in the upper and lower layers.

NOTE: Features are not computed for the bottom and top most layers in the pyramid.
NOTE: See discussion of scalePower inside of FeatureLaplacePyramid.

[1] Krystian Mikolajczyk and Cordelia Schmid, "Indexing based on scale invariant interest points" ICCV 2001. Proceedings.
[2] Lindeberg, T., "Feature detection with automatic scale selection." IJCV 30(2) (1998) 79 – 116

See Also:

FactoryInterestPoint

Field Summary

Fields

Modifier and Type	Field and Description
protected boofcv.abst.filter.derivative.AnyImageDerivative<T,D>	computeDerivative
protected java.util.List<ScalePoint>	foundPoints
protected boofcv.struct.image.GrayF32[]	intensities
protected java.util.List<georegression.struct.point.Point2D_I16>[]	maximums
protected double	scalePower
protected int	spaceIndex

Constructor Summary

Constructors

Constructor and Description
FeaturePyramid(GeneralFeatureDetector<T,D> detector, boofcv.abst.filter.derivative.AnyImageDerivative<T,D> computeDerivative, double scalePower) Create a feature detector.

Method Summary

Modifier and Type	Method and Description
protected static boolean	checkMax(boofcv.core.image.border.ImageBorder_F32 inten, float bestScore, int c_x, int c_y)
void	detect(boofcv.struct.pyramid.PyramidFloat<T> ss) Searches for features inside the provided scale space
protected void	findLocalScaleSpaceMax(boofcv.struct.pyramid.PyramidFloat<T> ss, int layerID) Searches the pyramid layers up and down to see if the found 2D features are also scale space maximums.
java.util.List<ScalePoint>	getInterestPoints() Returns all the found interest points

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

intensities

protected boofcv.struct.image.GrayF32[] intensities

spaceIndex

protected int spaceIndex

maximums

protected java.util.List<georegression.struct.point.Point2D_I16>[] maximums

foundPoints

protected java.util.List<ScalePoint> foundPoints

computeDerivative

protected boofcv.abst.filter.derivative.AnyImageDerivative<T extends boofcv.struct.image.ImageGray,D extends boofcv.struct.image.ImageGray> computeDerivative

scalePower

protected double scalePower

Constructor Detail

FeaturePyramid

public FeaturePyramid(GeneralFeatureDetector<T,D> detector,
                      boofcv.abst.filter.derivative.AnyImageDerivative<T,D> computeDerivative,
                      double scalePower)

Create a feature detector.

Parameters:

detector - Point feature detector which is used to find candidates in each scale level

scalePower - Used to normalize feature intensity at different scales. For many features this should be one.

Method Detail

detect

public void detect(boofcv.struct.pyramid.PyramidFloat<T> ss)

Searches for features inside the provided scale space

Specified by:

detect in interface InterestPointScaleSpacePyramid<T extends boofcv.struct.image.ImageGray>

Parameters:

ss - Scale space of an image

findLocalScaleSpaceMax

protected void findLocalScaleSpaceMax(boofcv.struct.pyramid.PyramidFloat<T> ss,
                                      int layerID)

Searches the pyramid layers up and down to see if the found 2D features are also scale space maximums.

checkMax

protected static boolean checkMax(boofcv.core.image.border.ImageBorder_F32 inten,
                                  float bestScore,
                                  int c_x,
                                  int c_y)

getInterestPoints

public java.util.List<ScalePoint> getInterestPoints()

Description copied from interface: InterestPointScaleSpacePyramid

Returns all the found interest points

Specified by:

getInterestPoints in interface InterestPointScaleSpacePyramid<T extends boofcv.struct.image.ImageGray>

Returns:

List of found interest points.