التفاصيل البيبلوغرافية
| العنوان: |
Accounting for Phase Drifts in SSVEP-Based BCIs by Means of Biphasic Stimulation. |
| المؤلفون: |
Wu, Hung-Yi1, Lee, Po-Lei2, Chang, Hsiang-Chih2, Hsieh, Jen-Chuen1 |
| المصدر: |
IEEE Transactions on Biomedical Engineering. 05/01/2011, Vol. 58 Issue 5, p1394-1402. 9p. |
| مصطلحات موضوعية: |
*ELECTROENCEPHALOGRAPHY, *DATA mining, *BRAIN-computer interfaces, *VISUAL evoked response, *PHASE shifters, *DATA analysis, *FEATURE extraction, *ELECTRIC stimulation |
| مستخلص: |
This study proposes a novel biphasic stimulation technique to solve the issue of phase drifts in steady-state visual evoked potential (SSVEPs) in phase-tagged systems. Phase calibration was embedded in stimulus sequences using a biphasic flicker, which is driven by a sequence with alternating reference and phase-shift states. Nine subjects were recruited to participate in off-line and online tests. Signals were bandpass filtered and segmented by trigger signals into reference and phase-shift epochs. Frequency components of SSVEP in the reference and phase-shift epochs were extracted using the Fourier method with a 50% overlapped sliding window. The real and imaginary parts of the SSVEP frequency components were organized into complex vectors in each epoch. Hotelling's t-square test was used to determine the significances of nonzero mean vectors. The rejection of noisy data segments and the validation of gaze detections were made based on p values. The phase difference between the valid mean vectors of reference and phase-shift epochs was used to identify user's gazed targets in this system. Data showed an average information transfer rate of 44.55 and 38.21 bits/min in off-line and online tests, respectively. [ABSTRACT FROM PUBLISHER] |
| قاعدة البيانات: |
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