Figure 4.

Optimizing accuracy and information transfer rate. The figure on the left shows the relationship between the flash duration and letter classification accuracy with a single-flash sequence. The figure on the right shows the relationship between the number of flash sequences and classification accuracy using a flash duration of 3/64 s (i.e., 47 ms). The subject reached a maximum of 98% classification accuracy at three flash sequences, and a maximum of 60.5 bits/min at 92.2% accuracy (i.e., a selection every 4.5 s) at two flash sequences.