def compute_noise_cov(subject, hcp_path, noise_cov_fname=''):
if noise_cov_fname == '':
noise_cov_fname = meg.NOISE_COV.format(cond='empty_room')
if op.isfile(noise_cov_fname):
noise_cov = mne.read_cov(noise_cov_fname)
return noise_cov
utils.make_dir(utils.get_parent_fol(noise_cov_fname))
raw_noise = hcp.read_raw(subject=subject,
hcp_path=hcp_path,
data_type='noise_empty_room')
raw_noise.load_data()
# apply ref channel correction and drop ref channels
preproc.apply_ref_correction(raw_noise)
raw_noise.filter(0.50,
None,
method='iir',
iir_params=dict(order=4, ftype='butter'),
n_jobs=1)
raw_noise.filter(None,
60,
method='iir',
iir_params=dict(order=4, ftype='butter'),
n_jobs=1)
##############################################################################
# Note that using the empty room noise covariance will inflate the SNR of the
# evkoked and renders comparisons to `baseline` rather uninformative.
noise_cov = mne.compute_raw_covariance(raw_noise, method='empirical')
noise_cov.save(noise_cov_fname)
return noise_cov
def test_apply_ref_correction():
"""Test reference correction."""
raw = hcp.read_raw(data_type='rest', run_index=0, **hcp_params)
# raw.crop(0, 10).load_data()
raw.load_data()
# XXX terrible hack to have more samples.
# The test files are too short.
raw.append(raw.copy())
meg_picks = mne.pick_types(raw.info, meg=True, ref_meg=False)
orig = raw[meg_picks[0]][0][0]
apply_ref_correction(raw)
proc = raw[meg_picks[0]][0][0]
assert_true(np.linalg.norm(orig) > np.linalg.norm(proc))
def test_apply_ref_correction():
"""Test reference correction."""
raw = hcp.read_raw(data_type='rest', run_index=0, **hcp_params)
# raw.crop(0, 10).load_data()
raw.load_data()
# XXX terrible hack to have more samples.
# The test files are too short.
raw.append(raw.copy())
meg_picks = mne.pick_types(raw.info, meg=True, ref_meg=False)
orig = raw[meg_picks[0]][0][0]
apply_ref_correction(raw)
proc = raw[meg_picks[0]][0][0]
assert_true(np.linalg.norm(orig) > np.linalg.norm(proc))
def preproc_annot_filter(subj_fold, raw, hcp_params):
"""Helper to annotate bad segments and apply Butterworth freq filtering"""
# apply ref channel correction
preproc.apply_ref_correction(raw)
# construct MNE annotations
annots = hcp.read_annot(**hcp_params)
bad_seg = (annots['segments']['all']) / raw.info['sfreq']
annotations = mne.Annotations(bad_seg[:, 0],
(bad_seg[:, 1] - bad_seg[:, 0]),
description='bad')
raw.annotations = annotations
# Read all bad channels (concatenated from all runs)
bad_ch_file = op.join(hcp_path, subj_fold, 'unprocessed', 'MEG',
'prebad_chans.txt')
with open(bad_ch_file, 'rb') as prebad_file:
prebad_chs = prebad_file.readlines()
raw.info['bads'].extend([ch.strip() for ch in prebad_chs]) # remove '\n'
#raw.info['bads'].extend(annots['channels']['all'])
#print('Bad channels added: %s' % annots['channels']['all'])
# Band-pass filter (by default, only operates on MEG/EEG channels)
# Note: MNE complains on Python 2.7
raw.filter(filt_params['lp'],
filt_params['hp'],
method=filt_params['method'],
filter_length=filt_params['filter_length'],
l_trans_bandwidth='auto',
h_trans_bandwidth='auto',
phase=filt_params['phase'],
n_jobs=-1)
return raw, annots
info_from=dict(data_type=data_type, run_index=run_index))
fwd = src_outputs['fwd']
del src_outputs
#=================================================================
# just using baseline to compute the noise cov
# after this, using empty room noise
#noise_cov = mne.compute_covariance(hcp_epochs, tmax=-0.5,method=['shrunk', 'empirical'])
#=================================================================
# Now we can compute the noise covariance. For this purpose we will apply
# the same filtering as was used for the computations of the ERF
raw_noise = hcp.read_raw(subject=subject,
hcp_path=hcp_path,
data_type='noise_empty_room')
raw_noise.load_data()
# apply ref channel correction and drop ref channels
preproc.apply_ref_correction(raw_noise)
# Note: MNE complains on Python 2.7
raw_noise.filter(0.50,
None,
method='iir',
iir_params=dict(order=4, ftype='butter'),
n_jobs=1)
raw_noise.filter(None,
60,
method='iir',
iir_params=dict(order=4, ftype='butter'),
n_jobs=1)
#Note that using the empty room noise covariance will inflate the SNR of the
#evkoked and renders comparisons to `baseline` rather uninformative.
noise_cov = mne.compute_raw_covariance(raw_noise, method='empirical')
src_params=dict(add_dist=False),
info_from=dict(data_type=data_type, run_index=run_index))
fwd = src_outputs['fwd']
##############################################################################
# Now we can compute the noise covariance. For this purpose we will apply
# the same filtering as was used for the computations of the ERF in the first
# place. See also :ref:`tut_reproduce_erf`.
raw_noise = hcp.read_raw(subject=subject, hcp_path=hcp_path,
data_type='noise_empty_room')
raw_noise.load_data()
# apply ref channel correction and drop ref channels
preproc.apply_ref_correction(raw_noise)
# Note: MNE complains on Python 2.7
raw_noise.filter(0.50, None, method='iir',
iir_params=dict(order=4, ftype='butter'), n_jobs=1)
raw_noise.filter(None, 60, method='iir',
iir_params=dict(order=4, ftype='butter'), n_jobs=1)
##############################################################################
# Note that using the empty room noise covariance will inflate the SNR of the
# evkoked and renders comparisons to `baseline` rather uninformative.
noise_cov = mne.compute_raw_covariance(raw_noise, method='empirical')
##############################################################################
# Now we assemble the inverse operator, project the data and show the results
# put single channel aside for comparison later
chan1 = raw[meg_picks[0]][0]
# add some plotting parameter
decim_fit = 100 # we lean a purely spatial model, we don't need all samples
decim_show = 10 # we can make plotting faster
n_fft = 2**15 # let's use long windows to see low frequencies
# we put aside the time series for later plotting
x_meg = raw[meg_picks][0][:, ::decim_show].mean(0)
x_meg_ref = raw[ref_picks][0][:, ::decim_show].mean(0)
###############################################################################
# Now we apply the ref correction (in place).
apply_ref_correction(raw)
###############################################################################
# That was the easiest part! Let's now plot everything.
plt.figure(figsize=(9, 6))
plot_psd(x_meg, Fs=raw.info['sfreq'], NFFT=n_fft, label='MEG', color='black')
plot_psd(x_meg_ref,
Fs=raw.info['sfreq'],
NFFT=n_fft,
label='MEG-REF',
color='red')
plot_psd(raw[meg_picks][0][:, ::decim_show].mean(0),
Fs=raw.info['sfreq'],
NFFT=n_fft,
label='MEG-corrected',
# put single channel aside for comparison later
chan1 = raw[meg_picks[0]][0]
# add some plotting parameter
decim_fit = 100 # we lean a purely spatial model, we don't need all samples
decim_show = 10 # we can make plotting faster
n_fft = 2 ** 15 # let's use long windows to see low frequencies
# we put aside the time series for later plotting
x_meg = raw[meg_picks][0][:, ::decim_show].mean(0)
x_meg_ref = raw[ref_picks][0][:, ::decim_show].mean(0)
###############################################################################
# Now we apply the ref correction (in place).
apply_ref_correction(raw)
###############################################################################
# That was the easiest part! Let's now plot everything.
plt.figure(figsize=(9, 6))
plot_psd(x_meg, Fs=raw.info['sfreq'], NFFT=n_fft, label='MEG', color='black')
plot_psd(x_meg_ref, Fs=raw.info['sfreq'], NFFT=n_fft, label='MEG-REF',
color='red')
plot_psd(raw[meg_picks][0][:, ::decim_show].mean(0), Fs=raw.info['sfreq'],
NFFT=n_fft, label='MEG-corrected', color='orange')
plt.legend()
plt.xticks(np.log10([0.1, 1, 10, 100]), [0.1, 1, 10, 100])
plt.xlim(np.log10([0.1, 300]))
plt.xlabel('log10(frequency) [Hz]')
