臺灣博碩士論文加值系統

根據視覺誘發電位(Steady-State Visual Evoked Potentials, SSVEP)設計的大腦人機介面(Brain-Computer Interface, BCI)並執行特定動作已經是腦波在科學方面應用常見的例子，針對不同頻率所造成的反應，發現出兩個問題：若刺激為低頻，會有不舒適的現象，反之刺激若為高頻則誘發能量反應不明顯。從演算法或是硬體其實都沒有辦法改善這兩種狀況。
本論文提出改變刺激源呈現方式：調整刺激源Onset、和Offset的時間，藉以達成降低疲勞度的好處，不僅可以改變刺激源外觀，還可以保留大部分的誘發能量，達到既不耗損能量、又能夠提高舒適度的非對稱低頻閃爍刺激源。
在應用方面將非對稱刺激源利用相位編碼(Phase Coding)控制家電，其正確率平均可達到接近90%，簡單來說改變了刺激源的方式並不會造成推動BCI系統上面的影響，利用這樣的變化所帶來的好處，可以使受測者更舒適。

Due to high transfer rate (ITR), minimal training and noninvasiveness of the features in electroencephalography (EEG) system, steady-state visual evoked potentials (SSVEP) recorded from occipital scalp have been used as signal input for implementing brain computer interface (BCI) systems. These SSVEP-based BCIs require subjects to gaze at one or more flickering sources to evoke SSVEPs for system control. Nevertheless, due to the frequency preference of SSVEPs in human, the flickering frequency used for SSVEP stimulation is usually controlled lower than 27 Hz. The use of stimulation frequency equaled or lower to medium stimulation range (? 27 Hz) inevitably causes subjects’ uncomfortableness. Accordingly, this thesis aims to present a brain-computer interface (BCI) with adjustable on-off duration in order to suppress users’ uncomfortableness. The proposed system has been used to control six functions of a remote controller with acceptable accuracy (~90%) and high information transfer rate (ITR).

中文摘要 I
Abstract II
致謝 III
圖目錄 VI
表目錄 X
第一章 緒論 1
第二章 視覺誘發腦波與大腦人機介面系統介紹 2
2.1 腦波 2
2.2 視覺誘發電位 6
2.3 基於視覺誘發電位的大腦人機介面 14
第三章 非對稱明暗閃爍視覺誘發電位研究 16
3.1 傳統閃爍刺激源介紹 16
3.2 非對稱明暗閃爍刺激源介紹、電路設計與相位分析 22
3.2.1 暗寬度調變 23
3.2.2 亮寬度調變 26
3.2.3 閃爍刺激源的電路設計 29
3.3 相位分析方法 34
3.5 腦波擷取 40
3.6 實驗設計和步驟 41
3.6.1 明暗閃爍刺激源性質研究 41
3.6.2 利用非對稱明暗閃爍刺激源搭配相位編碼控制遙控器 43
第四章 實驗結果 49
4.1 調整明暗閃爍產生之反應 49
4.2 相位編碼及時控制應用結果 60
第五章 結論與未來展望 63
Reference 64

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台北榮總整合性腦功能研究 http://ibru.vghtpe.gov.tw/chinese/eeg.htm
腦波介紹 http://memo.cgu.edu.tw/yun-ju/cguweb/SciLearn/Introduction/intro03Brain/brain05.htm
http://li.tmu.edu.tw/slide/Computer_Med/index.htm