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## jAudioFeatureExtractor.AudioFeatures
クラス MagnitudeSpectrum

    java.lang.Object
      jAudioFeatureExtractor.AudioFeatures.FeatureExtractor
          jAudioFeatureExtractor.AudioFeatures.MagnitudeSpectrum

    public class MagnitudeSpectrum

extends FeatureExtractor

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

The magnitude 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 square root of this is then found and 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
`MagnitudeSpectrum()` 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

### MagnitudeSpectrum

    public MagnitudeSpectrum()

  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`

概要 | パッケージ | クラス | 階層ツリー | 非推奨 API | 索引 | ヘルプ
前のクラス 次のクラス | フレームあり フレームなし
概要: 入れ子 | フィールド | コンストラクタ | メソッド | 詳細: フィールド | コンストラクタ | メソッド