虛擬環境中手部操作任務對視覺疲勞之影響

The Effect of Hand Operational Tasks on Visual Fatigue in Virtual Environment

連偉傑(Wei-Chieh Lien)

指導教授 ： 林久翔 ； 呂志維

中原大學/電機資訊學院/工業與系統工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200873

摘要

本研究目的為在虛擬環境中，使用者對於各種雙眼像差與觀看時間長短在完成Fitts’ Law實驗中使用者視覺疲勞與績效的影響。
　　受試者分為青年五位與中高年齡者五位。受試者首先將測量實驗前的閃光融合閾值並準備開始Fitts’ Law實驗，受試者必須將遠處之目標物件進行拖曳至中央之起始點，觀測者記錄每次之移動時間與紀錄失誤次數。進行實驗時，將於20分鐘後每10分鐘測量受試者之閃光融合閾值，而後繼續進行實驗，直到將所有實驗組合完成。
　　關於視覺疲勞，在60分鐘與實驗前的閃光融合閾值衰減有顯著的降低，並且與年齡的增長而更加的嚴重，像差與時間有交互作用，因此像差越大、年齡的增長與持續的時間將會使得視覺疲勞的程度變得更加嚴重。
　　在手部移動任務中，難度越困難操作時間越長並且年齡將會影響著操作績效的結果，隨著年齡的增長操作時間也將增加，當青年隨著像差的改變操作績效也隨之改變，中高年齡者對於像差不同操作績效並沒有顯著影響，但在像差9公分嚴重了影響老年人的錯誤率，隨著年齡的增長，手部操作任務的處理能力有相當大的衰退。
　　本研究發現在不同像差的虛擬環境中進行手部操作任務的視覺疲勞與任務績效測量時，越高的像差將會影響到視覺疲勞與錯誤率的提升，隨著操作任務的操作時間視覺疲勞將會逐漸的嚴重，所以使用虛擬實境執行操作型任務將不適合連續操作超過一個小時，並且像差不建議超過視角2.06度。

關鍵字

像差 ； 費茲定律 ； 虛擬實境 ； 移動時間

並列摘要

The objective of this study is to investigate users visual fatigue and hand movement performance using Fitts’ Law in Virtual Environment.
　　There are 5 young people and 5 older adults involved in this study. Every participant must be measured for the Critical Flicker Fusion (CFF) frequency and perform the Fitts’ Law task. Task Movement Time (MT) and error rate were recorded. The CFF value was measured in every 10 minutes after 20 minutes later.
　　The results found that the CFF decrement from the beginning of experiment to 60 minutes later was significantly different . The older adults experienced more visual fatigue than the young group. The parallax and the time interaction was significant. The more parallax, the longer time will result in more visual fatigue. According to the Fitts’ task experiment result, the Index of Difficulty (ID) and age have significant effects. The Movement Time for the young group changed with the parallax, but the older adults did not. In 9cm parallax, the older adult’s error rate became very high. Finally, the older adult’s throughput (TP) is smaller than the young group.
　　In this study, we found the high parallax will result in visual fatigue and the error rate of the movement task increases with very high parallax. When the task time becomes longer the visual fatigue also becomes more apparent.
　　We suggest the operation time should be less than one hour and the parallax less than 9cm (equivalent to a visual angle of 2.06 degrees) when performing interactive tasks in Virtual Environment.

並列關鍵字

Virtual Reality ； Fitts’ Law ； Parallax ； Movement Time

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