jAudioFeatureExtractor.AudioFeatures
Class FractionOfLowEnergyWindows

java.lang.Object
  extended by jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
      extended by jAudioFeatureExtractor.AudioFeatures.FractionOfLowEnergyWindows

public class FractionOfLowEnergyWindows
extends FeatureExtractor

A feature extractor that extracts the Fraction Of Low Energy Windows from window to window. This is a good measure of how much of a signal is quiet relative to the rest of a signal. No extracted feature values are stored in objects of this class.

Daniel McEnnis 05-07-05 added number_of_windows as editable property. Added getElement, setElement, and clone

Daniel McEnnis 05-08-05 added setWindow to permit this feature to be edited by GlobalWindow frame.

Author:
Cory McKay

Field Summary
 
Fields inherited from class jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
definition, dependencies, offsets, parent
 
Constructor Summary
FractionOfLowEnergyWindows()
          Basic constructor that sets the definition and dependencies (and their offsets) of this feature.
 
Method Summary
 java.lang.Object clone()
          Create an identical copy of this feature.
 double[] extractFeature(double[] samples, double sampling_rate, double[][] other_feature_values)
          Extracts this feature from the given samples at the given sampling rate and given the other feature values.
 java.lang.String getElement(int index)
          Function permitting an unintelligent outside function (ie.
 void setElement(int index, java.lang.String value)
          Function permitting an unintelligent outside function (ie.
 void setWindow(int n)
          Function that must be overridden to allow this feature to be set globally by GlobalChange frame.
 
Methods inherited from class jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
getDepenedencies, getDepenedencyOffsets, getFeatureDefinition, setParent
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FractionOfLowEnergyWindows

public FractionOfLowEnergyWindows()
Basic constructor that sets the definition and dependencies (and their offsets) of this feature.

Method Detail

extractFeature

public double[] extractFeature(double[] samples,
                               double sampling_rate,
                               double[][] other_feature_values)
                        throws java.lang.Exception
Extracts this feature from the given samples at the given sampling rate and given the other feature values.

In the case of this feature the sampling_rate is ignored.

Specified by:
extractFeature in class FeatureExtractor
Parameters:
samples - The samples to extract the feature from.
sampling_rate - The sampling rate that the samples are encoded with.
other_feature_values - The values of other features that are needed to calculate this value. The order and offsets of these features must be the same as those returned by this class's getDependencies and getDependencyOffsets methods respectively. The first indice indicates the feature/window and the second indicates the value.
Returns:
The extracted feature value(s).
Throws:
java.lang.Exception - Throws an informative exception if the feature cannot be calculated.

setWindow

public void setWindow(int n)
               throws java.lang.Exception
Function that must be overridden to allow this feature to be set globally by GlobalChange frame.

Overrides:
setWindow in class FeatureExtractor
Parameters:
n - the number of windows of offset to be used in calculating this feature
Throws:
java.lang.Exception

getElement

public java.lang.String getElement(int index)
                            throws java.lang.Exception
Function permitting an unintelligent outside function (ie. EditFeatures frame) to get the default values used to populate the table's entries. The correct index values are inferred from definition.attribute value.

Overrides:
getElement in class FeatureExtractor
Parameters:
index - which of AreaMoment's attributes should be edited.
Throws:
java.lang.Exception

setElement

public void setElement(int index,
                       java.lang.String value)
                throws java.lang.Exception
Function permitting an unintelligent outside function (ie. EditFeatures frame) to set the default values used to popylate the table's entries. Like getElement, the correct index values are inferred from the definition.attributes value.

Overrides:
setElement in class FeatureExtractor
Parameters:
index - attribute to be set
value - new value of the attribute
Throws:
java.lang.Exception

clone

public java.lang.Object clone()
Create an identical copy of this feature. This permits FeatureExtractor to use the prototype pattern to create new composite features using metafeatures.

Specified by:
clone in class FeatureExtractor