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git-svn-id: svn+ssh://svn.code.sf.net/p/cmusphinx/code/trunk/SphinxTrain@9613 94700074-3cef-4d97-a70e-9c8c206c02f5
41 lines
1.1 KiB
Python
41 lines
1.1 KiB
Python
# Copyright (c) 2006 Carnegie Mellon University
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#
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# You may copy and modify this freely under the same terms as
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# Sphinx-III
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"""Compute Sphinx-III 1s_c_d_dd features.
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This module provides a compute() function to compute 39-dimensional
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single-stream features consisting of cepstra and their first and
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second time derivatives. This is the default feature type used for
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Sphinx-III continuous density acoustic models.
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"""
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__author__ = "David Huggins-Daines <dhuggins@cs.cmu.edu>"
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__version__ = "$Revision$"
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from numpy import zeros, concatenate
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def compute(mfcc):
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"""Compute 39-dimensional single-stream features consisting of cepstra
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and their first and second time derivatives."""
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r, c = mfcc.shape
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# Pad the features to compute dcep, ddcep
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pad = concatenate((zeros((3,c)), mfcc, zeros((3,c))))
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# Now create the output array
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feat = zeros((r, c*3),'d')
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# cep
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feat[:, 0:13] = mfcc
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# dcep = mfc[2] - mfc[-2]
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feat[:, 13:26] = (pad[5:-1] - pad[1:-5])
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# ddcep = (mfc[3] - mfc[-1]) - (mfc[1] - mfc[-3])
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feat[:, 26:] = (pad[6:] - pad[2:-4]) - (pad[4:-2] - pad[0:-6])
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return feat
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