jAudioFeatureExtractor.AudioFeatures
クラス PowerSpectrum

java.lang.Object
  上位を拡張 jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
      上位を拡張 jAudioFeatureExtractor.AudioFeatures.PowerSpectrum

public class PowerSpectrum
extends FeatureExtractor

A feature extractor that extracts the FFT power spectrum from a set of samples. This is a good measure of the power of different frequency components within a window.

The power spectrum is found by first calculating the FFT with a Hanning window. The magnitude spectrum value for each bin is found by first summing the squares of the real and imaginary components. The result is divided by the number of bins.

The dimensions of this feature depend on the number of FFT bins, which depend on the number of input samples. The dimensions are stored in the definition field are therefore 0, in order to indicate this variability.

No extracted feature values are stored in objects of this class.

作成者:
Cory McKay

フィールドの概要
 
クラス jAudioFeatureExtractor.AudioFeatures.FeatureExtractor から継承されたフィールド
definition, dependencies, offsets, parent
 
コンストラクタの概要
PowerSpectrum()
          Basic constructor that sets the definition and dependencies (and their offsets) of this feature.
 
メソッドの概要
 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.
 
クラス jAudioFeatureExtractor.AudioFeatures.FeatureExtractor から継承されたメソッド
getDepenedencies, getDepenedencyOffsets, getElement, getFeatureDefinition, setElement, setParent, setWindow
 
クラス java.lang.Object から継承されたメソッド
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

コンストラクタの詳細

PowerSpectrum

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

メソッドの詳細

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 and other_feature_values parameters are ignored.

定義:
クラス FeatureExtractor 内の extractFeature
パラメータ:
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.
戻り値:
The extracted feature value(s).
例外:
java.lang.Exception - Throws an informative exception if the feature cannot be calculated.

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.

定義:
クラス FeatureExtractor 内の clone