net.beadsproject.beads.analysis.featureextractors
Class FFT

java.lang.Object
  net.beadsproject.beads.analysis.FeatureExtractor<float[],float[]>
      net.beadsproject.beads.analysis.featureextractors.FFT

Direct Known Subclasses:

PowerSpectrum

public class FFT
extends FeatureExtractor<float[],float[]>

FFT performs a Fast Fourier Transform and forwards half of the real part of the data to any listeners.

Field Summary

protected float[]	fftImag The imaginary part.
protected float[]	fftReal The real part.
protected java.util.ArrayList<FeatureExtractor<?,float[]>>	listeners

Fields inherited from class net.beadsproject.beads.analysis.FeatureExtractor

featureDescriptions, features, name, numFeatures

Constructor Summary

FFT()
Instantiates a new FFT.

Method Summary

void	addListener(FeatureExtractor<?,float[]> fe) Adds a FeatureExtractor as a listener.
protected static float[]	calculateImaginary(float[] spectrum, int length) Gets the imaginary part from the complex spectrum.
protected static float[]	calculateReal(float[] spectrum, int length) Gets the real part from the complex spectrum.
protected static void	fft(float[] data, int n, boolean isign) Perform FFT on data with given length, regular or inverse.
void	process(float[] data) Process some data of type P (specified by the class def).

Methods inherited from class net.beadsproject.beads.analysis.FeatureExtractor

getFeatureDescriptions, getFeatures, getName, getNumberOfFeatures, setName, setNumberOfFeatures

Methods inherited from class java.lang.Object

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

Field Detail

listeners

protected java.util.ArrayList<FeatureExtractor<?,float[]>> listeners

fftReal

protected float[] fftReal

The real part.

fftImag

protected float[] fftImag

The imaginary part.

Constructor Detail

FFT

public FFT()

Instantiates a new FFT.

Method Detail

process

public void process(float[] data)

Description copied from class: FeatureExtractor

Process some data of type P (specified by the class def). This method must be overidden by implementing classes.

Specified by:

process in class FeatureExtractor<float[],float[]>

Parameters:

data - the data.

addListener

public void addListener(FeatureExtractor<?,float[]> fe)

Adds a FeatureExtractor as a listener.

Parameters:

the - FeatureExtractor.

calculateReal

protected static float[] calculateReal(float[] spectrum,
                                       int length)

Gets the real part from the complex spectrum.

Parameters:

spectrum - complex spectrum.

length - length of data to use.

Returns:

real part of given length of complex spectrum.

calculateImaginary

protected static float[] calculateImaginary(float[] spectrum,
                                            int length)

Gets the imaginary part from the complex spectrum.

Parameters:

spectrum - complex spectrum.

length - length of data to use.

Returns:

imaginary part of given length of complex spectrum.

fft

protected static void fft(float[] data,
                          int n,
                          boolean isign)

Perform FFT on data with given length, regular or inverse.

Parameters:

data - the data.

length - the length.

isign - true for regular, false for inverse.