Package com.tagtraum.audiokern.audioprocessor

Class SpectralCentroidProcessor

java.lang.Object

com.tagtraum.jipes.AbstractSignalProcessor<LinearFrequencySpectrum,SpectralCentroidProcessor.Centroid>

com.tagtraum.audiokern.audioprocessor.SpectralCentroidProcessor

All Implemented Interfaces:

SignalProcessor<LinearFrequencySpectrum,SpectralCentroidProcessor.Centroid>, SignalPullProcessor<LinearFrequencySpectrum,SpectralCentroidProcessor.Centroid>, SignalSource<SpectralCentroidProcessor.Centroid>

public class SpectralCentroidProcessor
extends AbstractSignalProcessor<LinearFrequencySpectrum,SpectralCentroidProcessor.Centroid>

Computes the frequency of the centroid of a given power spectrum. The centroid is computed as the ratio of the weighted sum of all power coefficients and the regular sum of all power coefficients. Note that the SpectralCentroidProcessor.WeightFunction can be redefined. By default it's INDEX_PLUS_1.

Author:

Hendrik Schreiber

See Also:

FFT

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SpectralCentroidProcessor.Centroid
static interface	SpectralCentroidProcessor.WeightFunction	Weight function to be used when computing the weighted sum of all powers.

Field Summary

Fields

Modifier and Type	Field	Description
static SpectralCentroidProcessor.WeightFunction	DEFAULT_WEIGHT_FUNCTION
static SpectralCentroidProcessor.WeightFunction	INDEX_PLUS_1	index+1 (, because in beaTunes all indexes are zero-based).
static SpectralCentroidProcessor.WeightFunction	LOG2_FREQ_DIV_1000	log2(frequency/1000).

Fields inherited from class com.tagtraum.jipes.AbstractSignalProcessor

lastOut, signalProcessorSupport

Constructor Summary

Constructors

Constructor	Description
SpectralCentroidProcessor()

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
SpectralCentroidProcessor.WeightFunction	getWeightFunction()
int	hashCode()
boolean	isCollapseSub62_5Hz()
protected SpectralCentroidProcessor.Centroid	processNext(LinearFrequencySpectrum origSpectrum)
void	setCollapseSub62_5Hz(boolean collapseSub62_5Hz)	Collapses (sums) all coefficients below 62.5Hz into a single coefficient, in order to prevent non-zero DC-component or very low frequency components from having a disproportionate weight.
void	setWeightFunction(SpectralCentroidProcessor.WeightFunction weightFunction)
String	toString()

Methods inherited from class com.tagtraum.jipes.AbstractSignalProcessor

connectTo, connectTo, connectTo, disconnectFrom, flush, getConnectedProcessors, getConnectedSource, getId, getOutput, process, read, reset, setId

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

LOG2_FREQ_DIV_1000

public static final SpectralCentroidProcessor.WeightFunction LOG2_FREQ_DIV_1000

log2(frequency/1000). Used by the MPEG7 Audio Spectral Centroid, together with setCollapseSub62_5Hz(boolean).

INDEX_PLUS_1

public static final SpectralCentroidProcessor.WeightFunction INDEX_PLUS_1

index+1 (, because in beaTunes all indexes are zero-based).

See Also:

McKay, C. 2010. Automatic music classification with jMIR. Ph.D. Dissertation. McGill University, Canada., 3.2.6, p. 134

DEFAULT_WEIGHT_FUNCTION

public static final SpectralCentroidProcessor.WeightFunction DEFAULT_WEIGHT_FUNCTION

Constructor Detail

SpectralCentroidProcessor

public SpectralCentroidProcessor()

Method Detail

isCollapseSub62_5Hz

public boolean isCollapseSub62_5Hz()

getWeightFunction

public SpectralCentroidProcessor.WeightFunction getWeightFunction()

setWeightFunction

public void setWeightFunction(SpectralCentroidProcessor.WeightFunction weightFunction)

setCollapseSub62_5Hz

public void setCollapseSub62_5Hz(boolean collapseSub62_5Hz)

Collapses (sums) all coefficients below 62.5Hz into a single coefficient, in order to prevent non-zero DC-component or very low frequency components from having a disproportionate weight. See MPEG-7 ASC.

This is set to false by default.

Parameters:

collapseSub62_5Hz - true if you want to collapse the coefficients

processNext

protected SpectralCentroidProcessor.Centroid processNext(LinearFrequencySpectrum origSpectrum)
                                                  throws IOException

Specified by:

processNext in class AbstractSignalProcessor<LinearFrequencySpectrum,SpectralCentroidProcessor.Centroid>

Throws:

IOException

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object