""" ====================================================== Extract features using user-defined feature functions. ====================================================== The example shows how user-defined feature functions can be used in MNE-Features along with built-in feature functions. The code for this example is based on the method proposed in: Jean-Baptiste SCHIRATTI, Jean-Eudes LE DOUGET, Michel LE VAN QUYEN, Slim ESSID, Alexandre GRAMFORT, "An ensemble learning approach to detect epileptic seizures from long intracranial EEG recordings" Proc. IEEE ICASSP Conf. 2018 .. note:: This example is for illustration purposes, as other methods may lead to better performance on such a dataset (classification of auditory vs. visual stimuli). """ # Author: Jean-Baptiste Schiratti <jean.baptiste.schiratti@gmail.com> # Alexandre Gramfort <alexandre.gramfort@inria.fr> # License: BSD 3 clause from scipy.signal import medfilt import mne from mne.datasets import sample from sklearn.linear_model import LogisticRegression from sklearn.model_selection import (train_test_split, StratifiedKFold) from sklearn.pipeline import Pipeline from sklearn.preprocessing import StandardScaler from mne_features.feature_extraction import FeatureExtractor print(__doc__) ############################################################################### # Let us import the data using MNE-Python and epoch it: data_path = sample.data_path() raw_fname = data_path + '/MEG/sample/sample_audvis_filt-0-40_raw.fif' event_fname = data_path + '/MEG/sample/sample_audvis_filt-0-40_raw-eve.fif' tmin, tmax = -0.2, 0.5 event_id = dict(aud_l=1, vis_l=3) # Setup for reading the raw data raw = mne.io.read_raw_fif(raw_fname, preload=True) raw.filter(.5, None, fir_design='firwin') events = mne.read_events(event_fname) picks = mne.pick_types(raw.info, meg=False, eeg=True) # Read epochs epochs = mne.Epochs(raw, events, event_id, tmin, tmax, picks=picks, proj=True, baseline=None, preload=True) labels = epochs.events[:, -1] # get MEG and EEG data data = epochs.get_data() ############################################################################### # Define a feature function called ``compute_medfilt`` # ---------------------------------------------------- # # Here, the raw data is median filtered and the output signals are used # as features. def compute_medfilt(arr): """Median filtered signal as features. Parameters ---------- arr : ndarray, shape (n_channels, n_times) Returns ------- output : (n_channels * n_times,) """ return medfilt(arr, kernel_size=(1, 5)).ravel() ############################################################################### # Prepare for the classification task # ----------------------------------- # # In addition to the new feature function, we also propose to extract the # mean of the data: selected_funcs = [('medfilt', compute_medfilt), 'mean'] pipe = Pipeline([('fe', FeatureExtractor(sfreq=raw.info['sfreq'], selected_funcs=selected_funcs)), ('scaler', StandardScaler()), ('clf', LogisticRegression(random_state=42, solver='lbfgs'))]) skf = StratifiedKFold(n_splits=3, random_state=42) y = labels ############################################################################### # Print the accuracy score on a test dataset. X_train, X_test, y_train, y_test = train_test_split(data, y, test_size=0.2) accuracy = pipe.fit(X_train, y_train).score(X_test, y_test) print('Accuracy score = %1.3f' % accuracy)