TY - JOUR
T1 - Independence of amplitude-frequency and phase calibrations in an SSVEP-based BCI using stepping delay flickering sequences
AU - Chang, Hsiang Chih
AU - Lee, Po Lei
AU - Lo, Men Tzung
AU - Lee, I. Hui
AU - Yeh, Ting Kuang
AU - Chang, Chun Yen
N1 - Funding Information:
Manuscript received July 06, 2011; revised October 18, 2011, December 01, 2011; accepted December 06, 2011. Date of publication December 23, 2011; date of current version May 18, 2012. This work was supported in part by the National Central University, the Center for Dynamical Biomarkers and Translational Medicine (NSC 99-2911-1-008-100), in part by the National Science Council (99-2628-E-008-003, 99-2628-E-008-012), and in part by the Veterans General Hospital University System of Taiwan Joint Research Program (VGHUST98-98-P3-09).
PY - 2012
Y1 - 2012
N2 - 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.
AB - 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.
KW - Brain-computer interface (BCI)
KW - electroencephalography (EEG)
KW - steady-state visual evoked potential (SSVEP)
KW - stepping delay flickering sequence (SDFS)
UR - http://www.scopus.com/inward/record.url?scp=84861508064&partnerID=8YFLogxK
U2 - 10.1109/TNSRE.2011.2180925
DO - 10.1109/TNSRE.2011.2180925
M3 - 期刊論文
C2 - 22203724
AN - SCOPUS:84861508064
SN - 1534-4320
VL - 20
SP - 305
EP - 312
JO - IEEE Transactions on Neural Systems and Rehabilitation Engineering
JF - IEEE Transactions on Neural Systems and Rehabilitation Engineering
IS - 3
M1 - 6112237
ER -