plot_cross_session_multiple_datasets.py

"""
==================================
Cross-Session on Multiple Datasets
==================================

This example shows how to perform a cross-session analysis on two MI datasets
using a CSP+LDA pipeline

The cross session evaluation context will evaluate performance using a leave
one session out cross-validation. For each session in the dataset, a model
is trained on every other session and performance are evaluated on the current
session.
"""
# Authors: Sylvain Chevallier <sylvain.chevallier@uvsq.fr>
#
# License: BSD (3-clause)

import warnings

import matplotlib.pyplot as plt
import seaborn as sns
from mne.decoding import CSP
from sklearn.discriminant_analysis import LinearDiscriminantAnalysis as LDA
from sklearn.pipeline import make_pipeline

import moabb
from moabb.datasets import BNCI2014001, Zhou2016
from moabb.evaluations import CrossSessionEvaluation
from moabb.paradigms import LeftRightImagery


warnings.simplefilter(action="ignore", category=FutureWarning)
warnings.simplefilter(action="ignore", category=RuntimeWarning)
moabb.set_log_level("info")

###############################################################################
# Loading dataset
# ---------------
#
# Load 2 subjects of BNCI 2014-004 and Zhou2016 datasets, with 2 session each

subj = [1, 2]
datasets = [Zhou2016(), BNCI2014001()]
for d in datasets:
    d.subject_list = subj

###############################################################################
# Choose paradigm
# ---------------
#
# We select the paradigm MI, applying a bandpass filter (8-35 Hz) on
# the data and we will keep only left and right hand motor imagery

paradigm = LeftRightImagery(fmin=8, fmax=35)

##############################################################################
# Create pipelines
# ----------------
#
# Use the Common Spatial Patterns with 8 components and a Linear Discriminant
# Analysis classifier.

pipeline = {}
pipeline["CSP+LDA"] = make_pipeline(CSP(n_components=8), LDA())

##############################################################################
# Get data (optional)
# -------------------
#
# To get access to the EEG signals downloaded from the dataset, you could
# use `dataset.get_data(subjects=[subject_id])` to obtain the EEG under
# an MNE format, stored in a dictionary of sessions and runs.
# Otherwise, `paradigm.get_data(dataset=dataset, subjects=[subject_id])`
# allows to obtain the EEG data in scikit format, the labels and the meta
# information. The data are preprocessed according to the paradigm
# requirements.

# X_all, labels_all, meta_all = [], [], []
# for d in datasets:
#     # sessions = d.get_data(subjects=[2])
#     X, labels, meta = paradigm.get_data(dataset=d, subjects=[2])
#     X_all.append(X)
#     labels_all.append(labels)
#     meta_all.append(meta)

##############################################################################
# Evaluation
# ----------
#
# The evaluation will return a dataframe containing a single AUC score for
# each subject / session of the dataset, and for each pipeline.

overwrite = True  # set to True if we want to overwrite cached results

evaluation = CrossSessionEvaluation(
    paradigm=paradigm, datasets=datasets, suffix="examples", overwrite=overwrite
)
results = evaluation.process(pipeline)

print(results.head())
results.replace(["session_E", "session_T"], ["session_0", "session_1"], inplace=True)

##############################################################################
# Plot Results
# ----------------
#
# Here we plot the results, indicating the score for each session and subject

sns.catplot(
    data=results,
    x="session",
    y="score",
    hue="subject",
    col="dataset",
    kind="bar",
    palette="viridis",
)
plt.show()