boofcv.alg.tracker.klt

Class KltTracker<InputImage extends ImageSingleBand,DerivativeImage extends ImageSingleBand>

java.lang.Object

boofcv.alg.tracker.klt.KltTracker<InputImage,DerivativeImage>

public class KltTracker<InputImage extends ImageSingleBand,DerivativeImage extends ImageSingleBand>
extends java.lang.Object

A Kanade-Lucas-Tomasi (KLT) [1,2,3,4] point feature tracker for a single layer gray scale image. It tracks point features across a sequence of images by having each feature individually follow the image's gradient. Feature locations are estimated to within sub-pixel accuracy.

For this particular implementation of KLT, image derivatives is only needed when setDescription() is called. Tracker quality will degrade if features change orientation, but this technique is significantly faster.

Citations:

[1] Bruce D. Lucas and Takeo Kanade. An Iterative Image Registration Technique with an Application to Stereo Vision. International Joint Conference on Artificial Intelligence, pages 674-679, 1981.
[2] Carlo Tomasi and Takeo Kanade. Detection and Tracking of Point Features. Carnegie Mellon University Technical Report CMU-CS-91-132, April 1991.
[3] Jianbo Shi and Carlo Tomasi. Good Features to Track. IEEE Conference on Computer Vision and Pattern Recognition, pages 593-600, 1994.
[4] Stan Birchfield, http://www.ces.clemson.edu/~stb/klt/

Author:

Peter Abeles

Field Summary

Fields

Modifier and Type	Field and Description
protected KltConfig	config
protected DerivativeImage	derivX
protected DerivativeImage	derivY
protected ImageFloat32	descFeature
protected float	Ex
protected float	Ey
protected float	Gxx
protected float	Gxy
protected float	Gyy
protected InputImage	image
protected InterpolateRectangle<DerivativeImage>	interpDeriv
protected InterpolateRectangle<InputImage>	interpInput
protected int	lengthFeature
protected int	widthFeature

Constructor Summary

Constructors

Constructor and Description
KltTracker(InterpolateRectangle<InputImage> interpInput, InterpolateRectangle<DerivativeImage> interpDeriv, KltConfig config)

Method Summary

Methods

Modifier and Type	Method and Description
KltConfig	getConfig()
boolean	isFullyInside(float x, float y) Returns true if the features is entirely enclosed inside of the image.
boolean	setDescription(KltFeature feature) Sets the features description using the current image and the location of the feature stored in the feature.
void	setImage(InputImage image, DerivativeImage derivX, DerivativeImage derivY) Sets the current image it should be tracking with.
KltTrackFault	track(KltFeature feature) Updates the feature's location inside the image.

Methods inherited from class java.lang.Object

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

Field Detail

image

protected InputImage extends ImageSingleBand image

derivX

protected DerivativeImage extends ImageSingleBand derivX

derivY

protected DerivativeImage extends ImageSingleBand derivY

interpInput

protected InterpolateRectangle<InputImage extends ImageSingleBand> interpInput

interpDeriv

protected InterpolateRectangle<DerivativeImage extends ImageSingleBand> interpDeriv

config

protected KltConfig config

Gxx

protected float Gxx

Gyy

protected float Gyy

Gxy

protected float Gxy

Ex

protected float Ex

Ey

protected float Ey

widthFeature

protected int widthFeature

lengthFeature

protected int lengthFeature

descFeature

protected ImageFloat32 descFeature

Constructor Detail

KltTracker

public KltTracker(InterpolateRectangle<InputImage> interpInput,
          InterpolateRectangle<DerivativeImage> interpDeriv,
          KltConfig config)

Method Detail

setImage

public void setImage(InputImage image,
            DerivativeImage derivX,
            DerivativeImage derivY)

Sets the current image it should be tracking with.

Parameters:

image - Original input image.

derivX - Image derivative along the x-axis

derivY - Image derivative along the y-axis

setDescription

public boolean setDescription(KltFeature feature)

Sets the features description using the current image and the location of the feature stored in the feature. If the feature is an illegal location and cannot be set then false is returned.

Parameters:

feature - Feature description which is to be set. Location must be specified.

Returns:

true if the feature's description was modified.

track

public KltTrackFault track(KltFeature feature)

Updates the feature's location inside the image. The feature's position can be modified even if tracking fails.

Parameters:

feature - Feature being tracked.

Returns:

If the tracking was successful or not.

isFullyInside

public boolean isFullyInside(float x,
                    float y)

Returns true if the features is entirely enclosed inside of the image.

getConfig

public KltConfig getConfig()