contains the signal processing functionality More...

Functions
def	nabu.processing.processors.feature_computers.sigproc.framesig (sig, frame_len, frame_step, winfunc=lambda x:numpy.ones((x,)))
	Frame a signal into overlapping frames. More...

def	nabu.processing.processors.feature_computers.sigproc.deframesig (frames, siglen, frame_len, frame_step, winfunc=lambda x:numpy.ones((x,)))
	Does overlap-add procedure to undo the action of framesig. More...

def	nabu.processing.processors.feature_computers.sigproc.magspec (frames, nfft)
	Compute the magnitude spectrum of each frame in frames. More...

def	nabu.processing.processors.feature_computers.sigproc.powspec (frames, nfft)
	Compute the power spectrum of each frame in frames. More...

def	nabu.processing.processors.feature_computers.sigproc.logpowspec (frames, nfft, norm=1)
	Compute the log power spectrum of each frame in frames. More...

def	nabu.processing.processors.feature_computers.sigproc.preemphasis (signal, coeff=0.95)
	perform preemphasis on the input signal. More...

def	nabu.processing.processors.feature_computers.sigproc.snip (sig, rate, winlen, winstep)
	snip the edges of the utterance to fit the sliding window More...

Detailed Description

contains the signal processing functionality

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

This file includes routines for basic signal processing including framing and computing power spectra.

Author: : James Lyons 2012

Function Documentation

§ deframesig()

def nabu.processing.processors.feature_computers.sigproc.deframesig	(	frames,
		siglen,
		frame_len,
		frame_step,
		winfunc = `lambda x: numpy.ones((x, ))`
	)

Does overlap-add procedure to undo the action of framesig.

Parameters

frames	array of frames.
siglen	length of the desired signal, use 0 if unknown. Output will be truncated to siglen samples.
frame_len	length of each frame measured in samples.
frame_step	number of samples after the start of the previous frame that the next frame should begin.
winfunc	the analysis window to apply to each frame. By default no window is applied.

Returns: a 1-D signal.

§ framesig()

def nabu.processing.processors.feature_computers.sigproc.framesig	(	sig,
		frame_len,
		frame_step,
		winfunc = `lambda x: numpy.ones((x, ))`
	)

Frame a signal into overlapping frames.

Parameters

sig	the audio signal to frame.
frame_len	length of each frame measured in samples.
frame_step	number of samples after the start of the previous frame that the next frame should begin.
winfunc	the analysis window to apply to each frame. By default no window is applied.

Returns: an array of frames. Size is NUMFRAMES by frame_len.

§ logpowspec()

def nabu.processing.processors.feature_computers.sigproc.logpowspec	(	frames,
		nfft,
		norm = `1`
	)

Compute the log power spectrum of each frame in frames.

If frames is an NxD matrix, output will be NxNFFT.

Parameters

frames	the array of frames. Each row is a frame.
nfft	the FFT length to use. If NFFT > frame_len, the frames are zero-padded.
norm	If norm=1, the log power spectrum is normalised so that the max value (across all frames) is 1.

Returns: If frames is an NxD matrix, output will be NxNFFT. Each row will be the log power spectrum of the corresponding frame.

§ magspec()

def nabu.processing.processors.feature_computers.sigproc.magspec	(	frames,
		nfft
	)

Compute the magnitude spectrum of each frame in frames.

If frames is an NxD matrix, output will be NxNFFT.

Parameters

frames	the array of frames. Each row is a frame.
nfft	the FFT length to use. If NFFT > frame_len, the frames are zero-padded.

Returns: If frames is an NxD matrix, output will be NxNFFT. Each row will be the magnitude spectrum of the corresponding frame.

§ powspec()

def nabu.processing.processors.feature_computers.sigproc.powspec	(	frames,
		nfft
	)

Compute the power spectrum of each frame in frames.

If frames is an NxD matrix, output will be NxNFFT.

Parameters

frames	the array of frames. Each row is a frame.
nfft	the FFT length to use. If NFFT > frame_len, the frames are zero-padded.

Returns: If frames is an NxD matrix, output will be NxNFFT. Each row will be the power spectrum of the corresponding frame.

§ preemphasis()

def nabu.processing.processors.feature_computers.sigproc.preemphasis	(	signal,
		coeff = `0.95`
	)

perform preemphasis on the input signal.

Parameters

signal	The signal to filter.
coeff	The preemphasis coefficient. 0 is no filter, default is 0.95.

Returns: the filtered signal.

§ snip()

def nabu.processing.processors.feature_computers.sigproc.snip	(	sig,
		rate,
		winlen,
		winstep
	)

snip the edges of the utterance to fit the sliding window

Parameters

sig	audio signal
rate	sampling rate
winlen	length of the sliding window [s]
winstep	stepsize of the sliding window [s]

Returns: the snipped signal

Functions

Detailed Description

Function Documentation

§ deframesig()

§ framesig()

§ logpowspec()

§ magspec()

§ powspec()

§ preemphasis()

§ snip()