Figure 3.

Fast Fourier transform (FFT) results of the proposed detection ratio for COP and its velocity in both the ML and AP directions. (A) R_{COP_ML}: the detection ratio using COP data in the ML direction, (B) R_{VCOP_ML}: the detection ratio using COP velocity data in the ML direction, (C) R_{COP_AP}: the detection ratio using COP data in the AP direction, and (D) R_{VCOP_AP}: the detection ratio using COP velocity data in the AP direction. The asterisks (*) placed over the vertical bars denote a significant difference (p < 0.05). EC: eyes closed condition; EO: eyes open condition.