Package boofcv.alg.feature.detect.interest

Class FeaturePyramid<T extends ImageGray<T>,D extends ImageGray<D>>

java.lang.Object

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

All Implemented Interfaces:

InterestPointScaleSpacePyramid<T>

public class FeaturePyramid<T extends ImageGray<T>,D extends ImageGray<D>>
extends 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	Description
protected AnyImageDerivative<T,D>	computeDerivative
protected List<ScalePoint>	foundPoints
protected GrayF32[]	intensities
protected List<Point2D_I16>[]	maximums
protected double	scalePower
protected int	spaceIndex

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
protected static boolean	checkMax(ImageBorder_F32 inten, float bestScore, int c_x, int c_y)
void	detect(PyramidFloat<T> ss)	Searches for features inside the provided scale space
protected void	findLocalScaleSpaceMax(PyramidFloat<T> ss, int layerID)	Searches the pyramid layers up and down to see if the found 2D features are also scale space maximums.
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 Details

intensities

protected GrayF32[] intensities

spaceIndex

protected int spaceIndex

maximums

protected List<Point2D_I16>[] maximums

foundPoints

protected List<ScalePoint> foundPoints

computeDerivative

protected AnyImageDerivative<T extends ImageGray<T>,D extends ImageGray<D>> computeDerivative

scalePower

protected double scalePower

Constructor Details

FeaturePyramid

public FeaturePyramid(GeneralFeatureDetector<T,D> detector,
 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 Details

detect

public void detect(PyramidFloat<T> ss)

Searches for features inside the provided scale space

Specified by:

detect in interface InterestPointScaleSpacePyramid<T extends ImageGray<T>>

Parameters:

ss - Scale space of an image

findLocalScaleSpaceMax

protected void findLocalScaleSpaceMax(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(ImageBorder_F32 inten,
 float bestScore,
 int c_x,
 int c_y)

getInterestPoints

public List<ScalePoint> getInterestPoints()

Description copied from interface: InterestPointScaleSpacePyramid

Returns all the found interest points

Specified by:

getInterestPoints in interface InterestPointScaleSpacePyramid<T extends ImageGray<T>>

Returns:

List of found interest points.