Closed Loop Subject-Independent SSVEP Frequency Detection System Using CCA Features and Ensemble Learning Methods

Moein  Esfahani; Hosein  Najafi; Hossein  Sadati

doi:10.18502/fbt.v11i3.15878

Moein Esfahani Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran
Hosein Najafi Department of Computer Engineering, Islamic Azad University, Tehran, Iran
Hossein Sadati Department of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran

DOI: https://doi.org/10.18502/fbt.v11i3.15878

Keywords: Steady-State Visual Evoked Potentials; Canonical Correlation Analysis; Ensemble Learning; Machine Learning Operations; Brain-Computer Interface; Electroencephalogram.

Abstract

Purpose: In recent years, the use of Steady-State Visual Evoked Potentials (SSVEPs) in Brain-Computer Interface (BCI) systems has dramatically increased across several fields, such as rehabilitation, cognitive impairment, and brain disease or disorder detection, as well as artificial limbs, wheelchairs, and biomechanical systems. In this study, a novel method is proposed to help scientists develop more efficient BCI systems for Machine Learning Operations (MLOps). This study proposed a state-of-the-art method for detecting SSVEP-based stimulation frequencies with statistical models to design an optimal BCI system.

Materials and Methods: In this study, the Canonical Correlation Analysis (CCA) method has been implemented to extract features from the accessible-to-the-public Tsinghua University Benchmark dataset. A limited number of subjects are being studied. After completing feature selection methods and selecting the best subset of features using a specified feature selection method, the classification of the best features using machine learning-based classification methods has been completed. Furthermore, it is assumed that scientists will design and implement a system specifically for subjects. Models work for subjects independently. However, because model training is subject-specific, we must execute the proposed methods on each subject separately.

Results: The findings indicate that the novel suggested BCI system achieves an average accuracy of 83±9% in stimulation detection, which is higher than that of the traditional CCA approach with an accuracy of 80±11% (p<0.05).

Conclusion: Based on the findings, we demonstrated an increase in accuracy with the novel method. It was also discovered that by using the proposed techniques, it is possible to keep MLOps systems as an advantage.