Figure 12.

Recorded and extracted artifacts from the “Eyebrow” set. (A) Recorded EEG signals from the “Eyebrow” set. (B) The Hilbert–Huang time–frequency plot of the recorded EEG signals. (C) The Hilbert–Huang time–frequency plot of the extracted line noise ℜ{y₁(k)}. (D) The Hilbert–Huang time–frequency plot of the extracted EMG ℜ{y₂(k)}, 𝕵{y₂(k)}. (E) The power spectra (S) and pseudo-spectra (pS) of the recorded EMG, and the extracted signals y₁(k) and y₂(k). (F) Frequency components of the recorded EEG signals and the extracted artifacts around the 50-Hz frequency range. After extraction, the power line noise is contained in 𝕵{y₁}.