org.openimaj.image.feature.local.detector.dog.extractor

Class DominantOrientationExtractor

java.lang.Object

org.openimaj.image.feature.local.detector.dog.extractor.AbstractDominantOrientationExtractor

org.openimaj.image.feature.local.detector.dog.extractor.DominantOrientationExtractor

All Implemented Interfaces:

FeatureVectorExtractor<FloatFV,GradientScaleSpaceImageExtractorProperties<FImage>>

public class DominantOrientationExtractor
extends AbstractDominantOrientationExtractor

Extract the dominant orientations of a scale-space interest point by looking for peaks in its orientation histogram.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Field Summary

Fields

Modifier and Type	Field and Description
static float	DEFAULT_PEAK_THRESHOLD Default value for the threshold at which other peaks are detected relative to the biggest peak.
protected OrientationHistogramExtractor	oriHistExtractor
protected float	peakThreshold Threshold for peak detection.

Constructor Summary

Constructors

Constructor and Description
DominantOrientationExtractor() Construct with default values.
DominantOrientationExtractor(float peakThreshold, OrientationHistogramExtractor oriHistExtractor) Construct with given parameters.

Method Summary

Modifier and Type	Method and Description
float[]	extractFeatureRaw(GradientScaleSpaceImageExtractorProperties<FImage> properties) Extract an orientation histogram and find the dominant orientations by looking for peaks.
OrientationHistogramExtractor	getOriHistExtractor()

Methods inherited from class org.openimaj.image.feature.local.detector.dog.extractor.AbstractDominantOrientationExtractor

extractFeature

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PEAK_THRESHOLD

public static float DEFAULT_PEAK_THRESHOLD

Default value for the threshold at which other peaks are detected relative to the biggest peak. Lowe's IJCV paper suggests a value of 80%.

oriHistExtractor

protected OrientationHistogramExtractor oriHistExtractor

peakThreshold

protected float peakThreshold

Threshold for peak detection. A value of 1.0 would result in only a single peak being detected.

Constructor Detail

DominantOrientationExtractor

public DominantOrientationExtractor()

Construct with default values.

DominantOrientationExtractor

public DominantOrientationExtractor(float peakThreshold,
                                    OrientationHistogramExtractor oriHistExtractor)

Construct with given parameters.

Parameters:

peakThreshold - threshold at which other peaks are detected relative to the biggest peak

oriHistExtractor - the orientation histogram extractor

Method Detail

extractFeatureRaw

public float[] extractFeatureRaw(GradientScaleSpaceImageExtractorProperties<FImage> properties)

Extract an orientation histogram and find the dominant orientations by looking for peaks.

Specified by:

extractFeatureRaw in class AbstractDominantOrientationExtractor

Parameters:

properties - Properties describing the interest point in scale space.

Returns:

an array of the angles of the dominant orientations [-PI to PI].

getOriHistExtractor

public OrientationHistogramExtractor getOriHistExtractor()

Returns:

the orientation histogram extractor