• Journal of Broadcast Engineering
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• v.15 no.5
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• pp.607-616
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• 2010

The methods developed to measure visual fatigue so far are quite few and lack of validity, and more importantly, they do not figure out the complex properties of the visual fatigue. The purpose of the research was to analyze the factors comprising the visual fatigue and to develop the method to measure it validly. The results are summarized as follows. First, we found that the 3D visual fatigue was comprised of four independent factors (visual stress, eye pain, body pain and image blurring factors). Second, we developed 29 items that measure four factors of 3D visual fatigue. Finally, the watching duration and binocular disparities affected the visual fatigue as had been expected. These results imply that the developed method does measure the three dimensional fatigue validly.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.149-152
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• 2003

기존의 양안식 스테레오 디스플레이 시스템은 장면 내에 매우 큰 변이를 가지는 물체가 존재 할 경우에 시각피로를 유발하여 오랜 시간동안 시청하기가 어렵게 된다. 본 논문에서는 변이 기반 비대칭 필터링 기법을 제안하고, 이 기법의 시각 피로도에 미치는 영향을 주관적 평가를 통하여 고찰하며, 아울러 교차변이(crossed disparity) 및 비교차변이(uncrossed disparity)에 따른 시각 피로도에 미치는 영향의 변화 또한 고찰하였다. 실험 결과, 변이기반 비대칭 필터링은 시각 피로의 측면에서는 비교차변이만 존재하는 영상의 경우에는 원래의 스테레오 영상에 비해 큰 영향이 없거나, 오히려 필터링 수준에 따라 오히려 시각적 피로가 심하게 되는 결과를 나타내었다. 또한 교차변이의 경우에는 시파피로가 필터링 수준을 높임에 따라 조금씩 시각피로가 개선되는 결과를 나타내었다. 따라서, 비대칭 필터링에 의한 시각피로의 개선효과는 스테레오 영상 내 변이 종류와 그 크기, 시청자의 주시전 등 여러 요인에 따라 달라질 수 있음을 앞 수 있었다.

• Journal of Broadcast Engineering
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• v.18 no.4
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• pp.589-598
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• 2013

In order to understand 3D visual fatigue, it is necessary to examine the visual fatigue induced by camera parameters as well as that induced by a pre-existing 3D content. In the present study, we examined the effects of camera parameters, such as roll misalignment error, shooting distance and vergence condition on 3D visual fatigue and we modelled it. The results indicate that roll misalignment error, shooting distance and vergence condition affect 3D visual fatigue and the effect of roll misalignment error on 3D visual fatigue is evident specifically when screen disparity is relatively small.

• Science of Emotion and Sensibility
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• v.4 no.2
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• pp.63-68
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• 2001

We purpose to evaluate the fatigue of the error correcting task on monitoring with color temperature 2700 K, 4000 K and 6500 K. Results of questionnaire on subjective feeling of visual fatigue, mental fatigue and concentration. Visual fatigue and mental fatigue level were the lowest, concentration level was the highest and working performance was the best at 2700 K. At 6500 K, mental fatigue level was the highest and concentration level is the lowest. At 4000 K, visual fatigue level was the highest and working performance shown the worst ratio of correcting answers. As results, color temperature 2700 K is the best condition of color temperature to perform the error correcting task on monitoring.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.157-159
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• 2013

3D 산업은 그 실용적인 활용가치로 인해 주목받고 있다. 안정적인 3D 시청환경을 구축하기 위해서는 구현기술의 발전이 중요한 과제이지만, 현재의 기술 수준이 제한적이기 때문에 사용자가 시청환경에 대해 주관적으로 느끼는 부분을 다루는'휴먼팩터 (Human-factor)'를 연구하는 것 또한 중요하다. 그 중 시각피로는 안정적인 3D시청환경 구축과 직결되는 중요한 문제이며, 이러한 시각피로의 주요원인은 수렴-조절 불일치 현상이다. 본 연구는 수렴-조절 불일치에 직접적인 영향을 미치는 것이 화면시차 자체가 아니라 수렴각에 영향을 미치는 응시대상의 화면시차라고 가정하였다. 따라서 응시대상의 화면시차가 3D상황에서 수렴조절 불일치를 유발하는지를 규명하기 위하여 시청자들을 대상으로 응시대상의 화면시차를 조작하면서 그것이 시각피로에 영향을 주는지를 측정하였다. 결과는 예상대로 다른 대상들보다 응시대상의 시차가 시각피로에 주요한 영향력을 준다는 것을 함축하고 있으며, 그 외에 비-응시대상과 관련된 이슈들이 논의되었다. 결론적으로, 응시대상의 시차를 적절하게 통제함으로써 사용자의 시각피로를 최소화 할 수 있으며, 이는 시각 3D 환경을 구축하는 데에 도움이 될 것이다.

• Science of Emotion and Sensibility
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• v.12 no.2
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• pp.169-180
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• 2009

The present study have investigated the effect of the characteristics of stereoscopic images and viewing environment on visual fatigue. We manipulated the speed of stereo images with motion-in-depth and viewing distance, which were used as representative variables of the characteristics of stereo image and viewing environment, respectively. Visual fatigue was evaluated with use of a subjective questionnaire which is consisting of 5 different and independent factors: "Eye pain", "Visual stress," "Nauseousness", "Body stiffness", and "Blurriness". In general, when viewing time increased from 10 minutes to 20 and 40 minutes, observers felt severe visual fatigue. Among other factors, only the factor score of "Nauseousness" was significantly increased as the speed of object moving in depth became faster. When viewing distance was increased, the score of "Blurriness" was decreased. These results suggest that different kind of the visual fatigue might be induced depending on characteristics of the stereo images and viewing environment.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.572-583
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• 2012

In this study, we investigated visual fatigue in i3D system and basic factors that contribute to visual fatigue in the system. i3D is a type of glasses-free display which supports elementary manual interaction of users with the display. In Experiment 1, we performed open-ended survey of visual fatigue and collected responses from observers which then were used as survey questions for visual fatigue. The questions were validated by factor analysis from which we derived fatigue measurement scale. In Experiment 2, we measured visual fatigue in various conditions using survey questions obtained from Experiment 1. Using manual interaction (present/absent), viewing distance(1/2/4m), and viewing orientation($0/28/56^{\circ}$) as three factors in within-subject design, we measured visual fatigue in each condition. The results indicated that visual fatigue deceases with farther viewing distance, but viewing orientation and manual interaction does not influence visual fatigue. Although fatigue unexpectedly decreased in an extreme viewing condition (e.g., distance 1m, orientation $56^{\circ}$), the results were obtained because of technical limitation of glasses-free 3D display. General discussion provides discussion on limits of the current study and suggestions for future research.

• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.17-28
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• 2012

Recent development of 3D technologies made it possible that observers perceive 3D depth from two dimensional images. Despite this kind of technological development, when observers watch 3D display they experience 3D visual fatigue that they do not usually experience in real life. It is critical to measure visual fatigue in order to overcome the problem of 3D visual fatigue. The purpose of the present study was to develop a protocol to measure 3D visual fatigue based on an EEG signal and to examine its validity. The first experiment explored the possible ERP components that reflected visual fatigue in 2D and 3D conditions. The second experiment examined whether the feature of the component found in the first experiment was affected by the amount of binocular disparity. Both in Cz and Pz channels, the peak amplitude of P3 component was much lower in 3D rather than in 2D conditions, and it decreased as the amount of binocular disparity increased. The subjective 3D visual fatigue also increased with the amount of binocular disparity. These results imply that the peak amplitude of P3 component at Cz and Pz channels can be used as an index of 3D visual fatigue.

• Science of Emotion and Sensibility
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• v.19 no.1
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• pp.61-70
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• 2016

3D visual fatigue is known as one of the most important factors that interfere the commercial success of 3D contents. Vergence-accommodation conflict, which is known to occur when an observer watches an image containing binocular disparity presented on a 3D display, has been suggested as a major cause of 3D visual fatigue. This implies that any image incorporating binocular disparity might cause 3D visual fatigue. In order to reduce 3D visual fatigue, it would be necessary to consider indirect ways of reducing 3D visual fatigue as well as eliminating the direct causes of 3D visual fatigue. We have examined the effect of the variables that are expected to affect subjective 3D visual fatigue and these variables included the relative disparity contained in an image, viewing distance and viewing angle. We have also figured out the proper levels of the variables required to minimize 3D visual fatigue. The results indicate that observers began to report significant 3D visual fatigue when the crossed disparity contained in an image exceeded 7.22' and the vertical viewing angle was larger than 15 degree.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.11a
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• pp.251-254
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• 2001

조명 색온도에 따른 작업자의 피로도를 평가하기 위하여 세 종류의 조명 색온도 (2700K, 4000K, 6500K)를 실험변수로 하여 오류수정작업이 수행되었다. 작업수행 중 피로도와 집중도에 관한 주관평가를 실시한 결과, 시각 및 정신피로가 가장 적고 집중도가 높은 2700 K에서 작업수행도가 가장 좋았다. 6500 K에서는 정신피로를 가장 많이 느끼고 집중도가 제일 낮았으며, 4000 K에서 시각 및 정신피로를 가장 많이 느끼며 작업수행도는 가장 낮았다.