Common Spatio-Time-Frequency Patterns for Motor Imagery-Based Brain Machine Interfaces

Figure 4

Spatial patterns as the spatial amplitudes of the source signals ((a)–(d)) and the designed spatial weights ((e)–(h)). The amplitudes plotted by circles are 𝐚_𝑖⁽¹⁾ and the amplitudes plotted by cross are 𝐚_𝑖⁽²⁾ for 𝑖=1,…,4. The weights plotted by circles are 𝐰_𝑖⁽¹⁾ and the weights plotted by cross are 𝐰_𝑖⁽¹⁰⁾ for 𝑖=1,…,4. The horizontal axis represents the channel number.

(a) 1st source, 𝐚₁⁽¹⁾ and 𝐚₁⁽²⁾

(b) 2nd source, 𝐚₂⁽¹⁾ and 𝐚₂⁽²⁾

(c) 3rd source, 𝐚₃⁽¹⁾ and 𝐚₃⁽²⁾

(d) 4th source, 𝐚₄⁽¹⁾ and 𝐚₄⁽²⁾

(e) 1st weights, 𝐰₁⁽¹⁾ and 𝐰₁⁽¹⁰⁾

(f) 2nd weights, 𝐰₂⁽¹⁾ and 𝐰₂⁽¹⁰⁾

(g) 3rd weights, 𝐰₃⁽¹⁾ and 𝐰₃⁽¹⁰⁾

(h) 4th weights, 𝐰₄⁽¹⁾ and 𝐰₄⁽¹⁰⁾