| 摘要: | 大腦人機介面(brain computer interface, BCI)是一種不用透過肌肉活動，直接使用腦電波訊號(electroencephalogram, EEG)對外界裝置與儀器進行控制的一個溝通與控制管道。透過這個大腦人機介面，可以讓無法與外界溝通或無法自由移動的患者，傳遞他們所想要表達的訊息與自由移動，進而改善他們的生活。 近年來，穩態視覺誘發電位(steady state visual evoked potential, SSVEP)為基礎之大腦人機介面已被廣泛應用，利用不同頻率的視覺刺激，可以誘發大腦產生相同的腦電波頻率，以非侵入式的方式擷取腦電波訊號，進行腦電波訊號的辨識與編碼，進而轉換為各種控制指令。 本研究提供一種新的視覺刺激方法，利用電激發光(electro- luminescence, EL)薄膜冷光燈片，應用於穩態視覺誘發電位之腦波人機介面的判斷。不同於發光二極體(light emitting diode, LED)裝置，只能專注地凝視中心點位置，EL為均勻的場效發光，可以提供受測者比較舒適的視覺感受，減少疲倦的產生，進而提升EEG的穩定度與品質。從實驗的結果發現，其優點為受測者可以自由地專注在EL冷光平面燈片上的任何位置；此外，EL所需的驅動電流小、外型輕薄、具柔韌性、而且不需要背光源，不僅能降低腦波人機介面的功率消耗與成本，對於使用電池供電與攜帶方便的醫療設備而言，具有相當大的意義。 Brain computer Interface (BCI) is the equipment that recognizes user’s electroencephalography (EEG) patterns to communicate external environments or control external devices. A BCI allows disabled people or paralyzed patients to transmit their intentions, independent of peripheral muscle activities, so as to improve their living qualities. In recent years, steady state visual evoked potential (SSVEP)-based BCI has drawn great attentions, due to its advantages of simple architecture, fast responding time, and high information transfer rate (ITR). SSVEP-based BCI encodes visual stimulators with distinct stimulation frequencies. Subjects’ gazed targets can be recognized through identifications of SSVEP patterns, and converted into control commands for different applications. The research proposes a novel design of stimulation method for SSVEP-based BCI using electroluminescence (EL) device. Unlike the point lighting source done by LED, it provides paper lighting source with wider visual angle so that subjects can easily focus their attentions and perceive with better visual comfortableness. In addition, the EL device is lighter, cheaper, and more power efficient than traditional BCI lighting sources, such as light-emitted diode (LED), liquid crystal display (LCD), and cathode ray tube (CRT), lighting source. The EL display equipped BCI is slimmer than general BCI. Without using backlights, the EL device requires only small amount of electric driving current, which is an important feature for reducing the power consumption and production cost as well as the portability. |
