使用腦波訊號檢測視覺輻輳調節衝突在虛擬實境上的影響

Using Electroencephalography (EEG) to Examine the Effect of Vergence Accommodation Conflict on Virtual Reality

陳彥螢(Yen-Ying Chen)

指導教授 ： 黃乙白

國立交通大學/電機學院/光電工程系所/碩士(2019年)

摘要

虛擬實境為使用者創造了一個三維的立體虛擬世界，讓使用者彷彿身歷其境一般，然而在觀看立體視覺畫面時，使用者通常會經歷視覺輻輳調節衝突(vergence accommodation conflict, VAC)，引起視覺上的不適感和精神疲勞感。本研究目的為藉由觀看五種不同程度輻輳調節衝突的三維貪食蛇影片，並以客觀與主觀的量測方式，來研究視覺輻輳調節衝突在虛擬實境之裝置對人的影響。在客觀量測方面，本研究透過獨立成份分析(independent component analysis, ICA)，將腦電波的訊號資料分成三個有相同偶極源的叢集：額葉、頂葉和顳葉。結果顯示，當視覺輻輳調節衝突發生時，頂葉和顳葉的阿爾法波(alpha wave 7~12 Hz)會有顯著的衰減，而額葉的腦波節律活動則沒有顯著變化；然而，量測不同程度之間的視覺輻輳調節衝突，額葉、頂葉和顳葉的腦波節律活動卻沒有顯著差異。在主觀量測方面，模擬器暈動症問卷(simulator sickness questionnaire, SSQ)的結果顯示，視覺輻輳調節衝突會引起輕微的動眼神經類不適，以及微乎其微的噁心和定向障礙類不適。此項研究結果表明，由視覺輻輳調節衝突所引起的不適感和精神疲勞感，可能僅是輕微而可以為虛擬實境使用者所接受的。

關鍵字

虛擬實境 ； 腦電波 ； 視覺輻輳調節衝突 ； 阿爾法波

並列摘要

Virtual reality (VR) creates a three-dimensional (3D) virtual world for users, simulating our experiences similar to or different from the real world. However, in stereo viewing, users are generally suffered from vergence accommodation conflict (VAC), which usually induces visual discomfort and mental fatigue. This thesis aims to investigate on how VAC would affect people on VR by manipulating five different levels of 3D Snake content between vergence and accommodation. Both objective and subjective measurements are conducted to examine the effect. For objective measurements, based on independent component analysis (ICA), electroencephalography (EEG) data can be decomposed into three clusters with equivalent dipole source locating in the frontal lobe, the parietal lobe and the occipital lobe. In response to VAC, the parietal and the occipital lobe exhibit significant alpha power attenuation, while the frontal lobe shows no significant differences between two different brain rhythmic activities. Besides, in response to the levels of disparity, the frontal, the parietal and the occipital lobe exhibit no significant changes in all brain rhythmic activities. For subjective measurements, the results of the Simulator Sickness Questionnaire (SSQ) shows that VAC slightly induces oculomotor symptoms and causes almost none of nausea and disorientation symptoms. These findings suggests that the discomfort and the mental fatigue caused by VAC may be slight and be acceptable for VR users.

並列關鍵字

Virtual Reality ； Electroencephalography ； Vergence Accommodation Conflict ； Alpha wave

參考文獻

[1] Riva G, B. M.-T. (1997). Virtual reality environments for psycho-neuro-physiological assessment and rehabilitation. In Medicine Meets Virtual Reality: Global Healthcare Grid, pp. 34-45.

[2] Jack D, Boian R, Merians AS, Tremaine M, Burdea GC, Adamovich SV, Recce M, Poizner H (2001). Virtual reality-enhanced stroke rehabilitation. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 9: 308-318.

[3] Sveistrup H. Motor rehabilitation using virtual reality: review (2004). J Neuroeng Rehabil. 1:10–18.

[4] Vince, John (1993). 10 Virtual Reality Techniques in Flight Simulation. Virtual Reality Systems, p. 135-157.

[5] Satava RM (1993). Virtual reality surgical simulator: The first steps. Surg Endosc, 7: 203–205.