Fig. 4
From: A novel channel selection method for optimal classification in different motor imagery BCI paradigms
The optimal channel topographies of nine subjects. Topographies demonstrate which part of the cortex area the selected optimal channels locate over. The color indicates the importance of a channel in MI classification, and the importance of a channel is determined by its weight which is the sum of weights of the selected features. For non-optimal channel (discarded channel), its weight is set to zero here. a1, a2, a3 represent three subjects from MI tasks paradigm, b1, b2, b3 are from two-class control paradigm and c1, c2, c3 are from four-class control paradigm