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java.lang.Objectedu.cmu.sphinx.frontend.BaseDataProcessor
edu.cmu.sphinx.frontend.transform.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
PROP_CEPSTRUM_LENGTH_DEFAULT
. 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 | |
static java.lang.String |
PROP_CEPSTRUM_LENGTH
The name of the sphinx property for the size of the ceptrum |
static int |
PROP_CEPSTRUM_LENGTH_DEFAULT
The default value for PROP_CEPSTRUM_LENGTH |
static java.lang.String |
PROP_NUMBER_FILTERS
The name of the Sphinx Property for the number of filters in the filterbank. |
static int |
PROP_NUMBER_FILTERS_DEFAULT
The default value for PROP_NUMBER_FILTERS. |
Constructor Summary | |
DiscreteCosineTransform()
|
Method Summary | |
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 has new data. |
void |
register(java.lang.String name,
Registry registry)
Register my properties. |
Methods inherited from class edu.cmu.sphinx.frontend.BaseDataProcessor |
getName, getPredecessor, getTimer, setPredecessor, toString |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
public static final java.lang.String PROP_NUMBER_FILTERS
public static final int PROP_NUMBER_FILTERS_DEFAULT
public static final java.lang.String PROP_CEPSTRUM_LENGTH
public static final int PROP_CEPSTRUM_LENGTH_DEFAULT
Constructor Detail |
public DiscreteCosineTransform()
Method Detail |
public void register(java.lang.String name, Registry registry) throws PropertyException
Configurable
register
in interface Configurable
register
in class BaseDataProcessor
PropertyException
public void newProperties(PropertySheet ps) throws PropertyException
Configurable
newProperties
in interface Configurable
newProperties
in class BaseDataProcessor
PropertyException
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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