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java.lang.Objectedu.cmu.sphinx.frontend.BaseDataProcessor
edu.cmu.sphinx.frontend.transform.DiscreteCosineTransform
public class DiscreteCosineTransform
Applies a logarithm and then a Discrete Cosine Transform (DCT) to the input data. The input data is normally the mel
spectrum. It has been proven that, for a sequence of real numbers, the discrete cosine transform is equivalent to the
discrete Fourier transform. Therefore, this class corresponds to the last stage of converting a signal to cepstra,
defined as the inverse Fourier transform of the logarithm of the Fourier transform of a signal. The property PROP_CEPSTRUM_LENGTH
refers to the dimensionality of the coefficients that are actually returned, defaulting to
13. When the input is mel-spectrum, the vector returned is the MFCC (Mel-Frequency
Cepstral Coefficient) vector, where the 0-th element is the energy value.
Field Summary | |
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static java.lang.String |
PROP_CEPSTRUM_LENGTH
The name of the sphinx property for the size of the ceptrum |
static java.lang.String |
PROP_NUMBER_FILTERS
The name of the Sphinx Property for the number of filters in the filterbank. |
Constructor Summary | |
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DiscreteCosineTransform()
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Method Summary | |
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Data |
getData()
Returns the next DoubleData object, which is the mel cepstrum of the input frame. |
void |
initialize()
Initializes this DataProcessor. |
void |
newProperties(PropertySheet ps)
This method is called when this configurable component needs to be reconfigured. |
Methods inherited from class edu.cmu.sphinx.frontend.BaseDataProcessor |
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getPredecessor, getTimer, setPredecessor, toString |
Methods inherited from class java.lang.Object |
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equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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@S4Integer(defaultValue=40) public static final java.lang.String PROP_NUMBER_FILTERS
@S4Integer(defaultValue=13) public static final java.lang.String PROP_CEPSTRUM_LENGTH
Constructor Detail |
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public DiscreteCosineTransform()
Method Detail |
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public void newProperties(PropertySheet ps) throws PropertyException
Configurable
newProperties
in interface Configurable
newProperties
in class BaseDataProcessor
ps
- a property sheet holding the new data
PropertyException
- if there is a problem with the properties.public void initialize()
BaseDataProcessor
initialize
in interface DataProcessor
initialize
in class BaseDataProcessor
public Data getData() throws DataProcessingException
getData
in interface DataProcessor
getData
in class BaseDataProcessor
DataProcessingException
- if a data processing error occurred
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