Fig 1.
Checkerboard paradigm (CBP) in a 6x6 matrix.
Left: Matrix with imaginary checkerboard superimposed over it; adjacent characters are assigned to different classes. Center: Characters arranged in a virtual matrix, each matrix represents a different class. In this example, the first column has been selected from the top matrix. Right: Actual display seen by user; a face is flashed on top of the selected characters from the virtual matrices.
Fig 2.
Combinatorial paradigm (COMB) with () flashing pattern.
Left: Each character is assigned a unique, two number identifier corresponding to the time it will be flashed. For example (1,3) indicates that the character will be flashed in the first and third flash. For simplicity, the characters in this figure are assigned indices sequentially, in practice the assignment would be random. In this case, we depict the third flash; so all characters corresponding to the number 3 are flashed. Right: The output seen by a user; a face is flashed over characters that are assigned flash index 3.
Table 1.
Cross subject mean offline selection rate (SR), accuracy (ACC), and information transfer rate (ITR), for each flashing pattern and classifier.
Table 2.
The offline selection rate (SR), accuracy (ACC), and information transfer rate (ITR), for each flashing pattern.
Table 3.
The online selection rate (SR), accuracy (ACC), and information transfer rate (ITR), for each flashing pattern.
Fig 3.
The average target response for each flashing pattern at CPz, POz, PO7, and PO8 for subject 2 when using the row/column (blue), checkerboard (green), and combinatorial (red) flashing paradigms.