Please use this identifier to cite or link to this item: http://rportal.lib.ntnu.edu.tw:80/handle/77345300/42478
Title: Independence of amplitude-frequency and phase calibrations in an SSVEP-based BCI using stepping delay flickering sequences
Authors: 國立臺灣師範大學科學教育研究所
Chang, H. C.
Lee, P. L.
Lo, M. T.
Lee, I. H.
Yeh, T. K.
Chang, C. Y.
Issue Date: 1-May-2012
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Abstract: This study proposes a steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) independent of amplitude-frequency and phase calibrations. Six stepping delay flickering sequences (SDFSs) at 32-Hz flickering frequency were used to implement a six-command BCI system. EEG signals recorded from Oz position were first filtered within 29-35 Hz, segmented based on trigger events of SDFSs to obtain SDFS epochs, and then stored separately in epoch registers. An epoch-average process suppressed the inter-SDFS interference. For each detection point, the latest six SDFS epochs in each epoch register were averaged and the normalized power of averaged responses was calculated. The visual target that induced the maximum normalized power was identified as the visual target. Eight subjects were recruited in this study. All subjects were requested to produce the “563241” command sequence four times. The averaged accuracy, command transfer interval, and information transfer rate (mean std.) values for all eight subjects were 97.38 5.97%, 3.56 0.68 s, and 42.46 11.17 bits/min, respectively. The proposed system requires no calibration in either the amplitude-frequency characteristic or the reference phase of SSVEP which may provide an efficient and reliable channel for the neuromuscular disabled to communicate with external environments.
URI: http://rportal.lib.ntnu.edu.tw/handle/77345300/42478
ISSN: 1534-4320
Other Identifiers: ntnulib_tp_C0701_01_087
Appears in Collections:教師著作

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