Independent Components Time-Frequency Purification With Channel Consensus Against Adversarial Attack in SSVEP-Based BCIs

Abstract

The Steady State Visual Evoked Potential (SSVEP) paradigm has been widely employed in various Brain-Computer Interface (BCI) systems. However, recent studies indicate that SSVEP is vulnerable to adversarial attacks, resulting in manipulated results and drastic degradation in recognition performance, which pose inconveniences and even risks to users. Noticing the fact that the adversarial attack on SSVEP is done by adding subtle waveform perturbations into random EEG channels, we propose Independent Components Time-Frequency Purification with Channel Consensus (ICTFP-CC) as a defensive strategy. In particular, we first detect and remove suspicious perturbations with independent component analysis from the time and frequency domain, and then reconstruct the purified EEG signals. Additionally, we introduce a voting mechanism to achieve channel consensus and enhance overall robustness. We conducted experiments on two public datasets and three SSVEP recognition algorithms. The results demonstrate that our method can significantly improve the classification accuracy and information transfer rate of attacked SSVEP signals by a maximum of 46.79 (%) and 62.87 (bits/min).