def derivative(signal):
'''
Calculate the derivative of an AnalogSignal.
Parameters
----------
signal : neo.AnalogSignal
The signal to differentiate. If `signal` contains more than one
channel, each is differentiated separately.
Returns
-------
neo.AnalogSignal
The returned object is an AnalogSignal containing the differences
between each successive sample value of the input signal divided by the
sampling period. Times are centered between the successive samples of
the input. The output signal will have the same number of channels as
the input signal.
Raises
------
TypeError
If the input signal is not a neo.AnalogSignal.
'''
if not isinstance(signal, neo.AnalogSignal):
raise TypeError('Input signal is not a neo.AnalogSignal!')
derivative_sig = neo.AnalogSignal(
np.diff(signal.as_quantity(), axis=0) / signal.sampling_period,
t_start=signal.t_start + signal.sampling_period / 2,
sampling_period=signal.sampling_period)
return derivative_sig
def derivative(signal):
'''
Calculate the derivative of an AnalogSignal.
Parameters
----------
signal : neo.AnalogSignal
The signal to differentiate. If `signal` contains more than one
channel, each is differentiated separately.
Returns
-------
neo.AnalogSignal
The returned object is an AnalogSignal containing the differences
between each successive sample value of the input signal divided by the
sampling period. Times are centered between the successive samples of
the input. The output signal will have the same number of channels as
the input signal.
Raises
------
TypeError
If the input signal is not a neo.AnalogSignal.
'''
if not isinstance(signal, neo.AnalogSignal):
raise TypeError('Input signal is not a neo.AnalogSignal!')
derivative_sig = neo.AnalogSignal(
np.diff(signal.as_quantity(), axis=0) / signal.sampling_period,
t_start=signal.t_start+signal.sampling_period/2,
sampling_period=signal.sampling_period)
return derivative_sig
def derivative(signal):
"""
Calculate the derivative of a `neo.AnalogSignal`.
Parameters
----------
signal : neo.AnalogSignal
The signal to differentiate. If `signal` contains more than one
channel, each is differentiated separately.
Returns
-------
derivative_sig : neo.AnalogSignal
The returned object is a `neo.AnalogSignal` containing the differences
between each successive sample value of the input signal divided by
the sampling period. Times are centered between the successive samples
of the input. The output signal will have the same number of channels
as the input signal.
Raises
------
TypeError
If `signal` is not a `neo.AnalogSignal`.
Examples
--------
>>> import neo
>>> import numpy as np
>>> import quantities as pq
>>> from elephant.signal_processing import derivative
>>> signal = neo.AnalogSignal([0, 3, 4, 11, -1], sampling_rate=1 * pq.Hz,
... units='mV')
>>> print(derivative(signal))
[[ 3.]
[ 1.]
[ 7.]
[-12.]] mV*Hz
"""
if not isinstance(signal, neo.AnalogSignal):
raise TypeError('Input signal is not a neo.AnalogSignal!')
derivative_sig = neo.AnalogSignal(
np.diff(signal.as_quantity(), axis=0) / signal.sampling_period,
t_start=signal.t_start + signal.sampling_period / 2,
sampling_period=signal.sampling_period)
return derivative_sig
def rauc(signal, baseline=None, bin_duration=None, t_start=None, t_stop=None):
'''
Calculate the rectified area under the curve (RAUC) for an AnalogSignal.
The signal is optionally divided into bins with duration `bin_duration`,
and the rectified signal (absolute value) is integrated within each bin to
find the area under the curve. The mean or median of the signal or an
arbitrary baseline may optionally be subtracted before rectification. If
the number of bins is 1 (default), a single value is returned for each
channel in the input signal. Otherwise, an AnalogSignal containing the
values for each bin is returned along with the times of the centers of the
bins.
Parameters
----------
signal : neo.AnalogSignal
The signal to integrate. If `signal` contains more than one channel,
each is integrated separately.
bin_duration : quantities.Quantity
The length of time that each integration should span. If None, there
will be only one bin spanning the entire signal duration. If
`bin_duration` does not divide evenly into the signal duration, the end
of the signal is padded with zeros to accomodate the final,
overextending bin.
Default: None
baseline : string or quantities.Quantity
A factor to subtract from the signal before rectification. If `'mean'`
or `'median'`, the mean or median value of the entire signal is
subtracted on a channel-by-channel basis.
Default: None
t_start, t_stop : quantities.Quantity
Times to start and end the algorithm. The signal is cropped using
`signal.time_slice(t_start, t_stop)` after baseline removal. Useful if
you want the RAUC for a short section of the signal but want the
mean or median calculation (`baseline='mean'` or `baseline='median'`)
to use the entire signal for better baseline estimation.
Default: None
Returns
-------
quantities.Quantity or neo.AnalogSignal
If the number of bins is 1, the returned object is a scalar or
vector Quantity containing a single RAUC value for each channel.
Otherwise, the returned object is an AnalogSignal containing the
RAUC(s) for each bin stored as a sample, with times corresponding to
the center of each bin. The output signal will have the same number
of channels as the input signal.
Raises
------
TypeError
If the input signal is not a neo.AnalogSignal.
TypeError
If `bin_duration` is not None or a Quantity.
TypeError
If `baseline` is not None, `'mean'`, `'median'`, or a Quantity.
'''
if not isinstance(signal, neo.AnalogSignal):
raise TypeError('Input signal is not a neo.AnalogSignal!')
if baseline is None:
pass
elif baseline is 'mean':
# subtract mean from each channel
signal = signal - signal.mean(axis=0)
elif baseline is 'median':
# subtract median from each channel
signal = signal - np.median(signal.as_quantity(), axis=0)
elif isinstance(baseline, pq.Quantity):
# subtract arbitrary baseline
signal = signal - baseline
else:
raise TypeError('baseline must be None, \'mean\', \'median\', '
'or a Quantity: {}'.format(baseline))
# slice the signal after subtracting baseline
signal = signal.time_slice(t_start, t_stop)
if bin_duration is not None:
# from bin duration, determine samples per bin and number of bins
if isinstance(bin_duration, pq.Quantity):
samples_per_bin = int(
np.round(
bin_duration.rescale('s') /
signal.sampling_period.rescale('s')))
n_bins = int(np.ceil(signal.shape[0] / samples_per_bin))
else:
raise TypeError(
'bin_duration must be a Quantity: {}'.format(bin_duration))
else:
# all samples in one bin
samples_per_bin = signal.shape[0]
n_bins = 1
# store the actual bin duration
bin_duration = samples_per_bin * signal.sampling_period
# reshape into equal size bins, padding the end with zeros if necessary
n_channels = signal.shape[1]
sig_binned = signal.as_quantity().copy()
sig_binned.resize(n_bins * samples_per_bin, n_channels, refcheck=False)
sig_binned = sig_binned.reshape(n_bins, samples_per_bin, n_channels)
# rectify and integrate over each bin
rauc = np.trapz(np.abs(sig_binned), dx=signal.sampling_period, axis=1)
if n_bins == 1:
# return a single value for each channel
return rauc.squeeze()
else:
# return an AnalogSignal with times corresponding to center of each bin
rauc_sig = neo.AnalogSignal(
rauc,
t_start=signal.t_start.rescale(bin_duration.units) +
bin_duration / 2,
sampling_period=bin_duration)
return rauc_sig
def rauc(signal, baseline=None, bin_duration=None, t_start=None, t_stop=None):
"""
Calculate the rectified area under the curve (RAUC) for a
`neo.AnalogSignal`.
The signal is optionally divided into bins with duration `bin_duration`,
and the rectified signal (absolute value) is integrated within each bin to
find the area under the curve. The mean or median of the signal or an
arbitrary baseline may optionally be subtracted before rectification.
Parameters
----------
signal : neo.AnalogSignal
The signal to integrate. If `signal` contains more than one channel,
each is integrated separately.
baseline : pq.Quantity or {'mean', 'median'}, optional
A factor to subtract from the signal before rectification.
If 'mean', the mean value of the entire `signal` is subtracted on a
channel-by-channel basis.
If 'median', the median value of the entire `signal` is subtracted on
a channel-by-channel basis.
Default: None
bin_duration : pq.Quantity, optional
The length of time that each integration should span.
If None, there will be only one bin spanning the entire signal
duration.
If `bin_duration` does not divide evenly into the signal duration, the
end of the signal is padded with zeros to accomodate the final,
overextending bin.
Default: None
t_start : pq.Quantity, optional
Time to start the algorithm.
If None, starts at the beginning of `signal`.
Default: None
t_stop : pq.Quantity, optional
Time to end the algorithm.
If None, ends at the last time of `signal`.
The signal is cropped using `signal.time_slice(t_start, t_stop)` after
baseline removal. Useful if you want the RAUC for a short section of
the signal but want the mean or median calculation (`baseline`='mean'
or `baseline`='median') to use the entire signal for better baseline
estimation.
Default: None
Returns
-------
pq.Quantity or neo.AnalogSignal
If the number of bins is 1, the returned object is a scalar or
vector `pq.Quantity` containing a single RAUC value for each channel.
Otherwise, the returned object is a `neo.AnalogSignal` containing the
RAUC(s) for each bin stored as a sample, with times corresponding to
the center of each bin. The output signal will have the same number
of channels as the input signal.
Raises
------
ValueError
If `signal` is not `neo.AnalogSignal`.
If `bin_duration` is not None or `pq.Quantity`.
If `baseline` is not None, 'mean', 'median', or `pq.Quantity`.
See Also
--------
neo.AnalogSignal.time_slice : how `t_start` and `t_stop` are used
Examples
--------
>>> import neo
>>> import numpy as np
>>> import quantities as pq
>>> from elephant.signal_processing import rauc
>>> signal = neo.AnalogSignal(np.arange(10), sampling_rate=20 * pq.Hz,
... units='mV')
>>> rauc(signal)
array(2.025) * mV/Hz
"""
if not isinstance(signal, neo.AnalogSignal):
raise ValueError('Input signal is not a neo.AnalogSignal!')
if baseline is None:
pass
elif baseline == 'mean':
# subtract mean from each channel
signal = signal - signal.mean(axis=0)
elif baseline == 'median':
# subtract median from each channel
signal = signal - np.median(signal.as_quantity(), axis=0)
elif isinstance(baseline, pq.Quantity):
# subtract arbitrary baseline
signal = signal - baseline
else:
raise ValueError("baseline must be either None, 'mean', 'median', or "
"a Quantity. Got {}".format(baseline))
# slice the signal after subtracting baseline
signal = signal.time_slice(t_start, t_stop)
if bin_duration is not None:
# from bin duration, determine samples per bin and number of bins
if isinstance(bin_duration, pq.Quantity):
samples_per_bin = int(
np.round(
bin_duration.rescale('s') /
signal.sampling_period.rescale('s')))
n_bins = int(np.ceil(signal.shape[0] / samples_per_bin))
else:
raise ValueError(
"bin_duration must be a Quantity. Got {}".format(bin_duration))
else:
# all samples in one bin
samples_per_bin = signal.shape[0]
n_bins = 1
# store the actual bin duration
bin_duration = samples_per_bin * signal.sampling_period
# reshape into equal size bins, padding the end with zeros if necessary
n_channels = signal.shape[1]
sig_binned = signal.as_quantity().copy()
sig_binned.resize(n_bins * samples_per_bin, n_channels, refcheck=False)
sig_binned = sig_binned.reshape(n_bins, samples_per_bin, n_channels)
# rectify and integrate over each bin
rauc = np.trapz(np.abs(sig_binned), dx=signal.sampling_period, axis=1)
if n_bins == 1:
# return a single value for each channel
return rauc.squeeze()
else:
# return an AnalogSignal with times corresponding to center of each bin
t_start = signal.t_start.rescale(bin_duration.units) + bin_duration / 2
rauc_sig = neo.AnalogSignal(rauc,
t_start=t_start,
sampling_period=bin_duration)
return rauc_sig
def rauc(signal, baseline=None, bin_duration=None, t_start=None, t_stop=None):
'''
Calculate the rectified area under the curve (RAUC) for an AnalogSignal.
The signal is optionally divided into bins with duration `bin_duration`,
and the rectified signal (absolute value) is integrated within each bin to
find the area under the curve. The mean or median of the signal or an
arbitrary baseline may optionally be subtracted before rectification. If
the number of bins is 1 (default), a single value is returned for each
channel in the input signal. Otherwise, an AnalogSignal containing the
values for each bin is returned along with the times of the centers of the
bins.
Parameters
----------
signal : neo.AnalogSignal
The signal to integrate. If `signal` contains more than one channel,
each is integrated separately.
bin_duration : quantities.Quantity
The length of time that each integration should span. If None, there
will be only one bin spanning the entire signal duration. If
`bin_duration` does not divide evenly into the signal duration, the end
of the signal is padded with zeros to accomodate the final,
overextending bin.
Default: None
baseline : string or quantities.Quantity
A factor to subtract from the signal before rectification. If `'mean'`
or `'median'`, the mean or median value of the entire signal is
subtracted on a channel-by-channel basis.
Default: None
t_start, t_stop : quantities.Quantity
Times to start and end the algorithm. The signal is cropped using
`signal.time_slice(t_start, t_stop)` after baseline removal. Useful if
you want the RAUC for a short section of the signal but want the
mean or median calculation (`baseline='mean'` or `baseline='median'`)
to use the entire signal for better baseline estimation.
Default: None
Returns
-------
quantities.Quantity or neo.AnalogSignal
If the number of bins is 1, the returned object is a scalar or
vector Quantity containing a single RAUC value for each channel.
Otherwise, the returned object is an AnalogSignal containing the
RAUC(s) for each bin stored as a sample, with times corresponding to
the center of each bin. The output signal will have the same number
of channels as the input signal.
Raises
------
TypeError
If the input signal is not a neo.AnalogSignal.
TypeError
If `bin_duration` is not None or a Quantity.
TypeError
If `baseline` is not None, `'mean'`, `'median'`, or a Quantity.
'''
if not isinstance(signal, neo.AnalogSignal):
raise TypeError('Input signal is not a neo.AnalogSignal!')
if baseline is None:
pass
elif baseline is 'mean':
# subtract mean from each channel
signal = signal - signal.mean(axis=0)
elif baseline is 'median':
# subtract median from each channel
signal = signal - np.median(signal.as_quantity(), axis=0)
elif isinstance(baseline, pq.Quantity):
# subtract arbitrary baseline
signal = signal - baseline
else:
raise TypeError(
'baseline must be None, \'mean\', \'median\', '
'or a Quantity: {}'.format(baseline))
# slice the signal after subtracting baseline
signal = signal.time_slice(t_start, t_stop)
if bin_duration is not None:
# from bin duration, determine samples per bin and number of bins
if isinstance(bin_duration, pq.Quantity):
samples_per_bin = int(np.round(
bin_duration.rescale('s')/signal.sampling_period.rescale('s')))
n_bins = int(np.ceil(signal.shape[0]/samples_per_bin))
else:
raise TypeError(
'bin_duration must be a Quantity: {}'.format(bin_duration))
else:
# all samples in one bin
samples_per_bin = signal.shape[0]
n_bins = 1
# store the actual bin duration
bin_duration = samples_per_bin * signal.sampling_period
# reshape into equal size bins, padding the end with zeros if necessary
n_channels = signal.shape[1]
sig_binned = signal.as_quantity().copy()
sig_binned.resize(n_bins * samples_per_bin, n_channels)
sig_binned = sig_binned.reshape(n_bins, samples_per_bin, n_channels)
# rectify and integrate over each bin
rauc = np.trapz(np.abs(sig_binned), dx=signal.sampling_period, axis=1)
if n_bins == 1:
# return a single value for each channel
return rauc.squeeze()
else:
# return an AnalogSignal with times corresponding to center of each bin
rauc_sig = neo.AnalogSignal(
rauc,
t_start=signal.t_start.rescale(bin_duration.units)+bin_duration/2,
sampling_period=bin_duration)
return rauc_sig
