다양한 시청환경에 따른 무안경식 interactive 3D 시스템의 시각피로도 측정

김정열(Jung-Yul Kim),김덕중(Duk-Joong Kim),김신우(ShinWoo Kim),이형철(Hyung-Chul O. Li) 한국HCI학회 2013 한국HCI학회 학술대회 Vol.2013 No.1

3D 디스플레이를 통해 입체감을 느낄 때에는 현실세계에서 입체감을 느낄 때와는 다르게 피로를 느끼게 된다. 이러한 피로에 대해 안경식 3D 디스플레이를 사용한 연구는 많았지만 무안경식 3D에 대한 연구는 아직까지 미비한 실정이다. i3D시스템이란 interactive 3D 시스템의 약자로 사용자가 간단한 손동작 등으로 콘텐츠와 상호작용이 가능하도록 제작한 무안경식 3D 디스플레이 시스템을 말한다. 본 연구에서는 현재 시연용으로 구현되어 있는 i3D시스템을 이용하여 이 시스템을 사용하는 다양한 시청 환경에서의 시각 피로를 측정하였다. 그 결과 시청거리가 멀어질수록 낮은 피로를 보였으며 시차가 작을수록 낮은 피로를 보였다. 시청각도의 경우 3D 입체상이 안정적으로 지각되지 않는 시청각도에서 높은 피로를 느끼는 것으로 나타났다. 또한 시청거리와 시청각도간의 상호작용 효과를 볼 수 있었는데, 3D가 안정적으로 지각되었을 때의 시청각도에서는 시청거리에 따라서 피로도가 감소하는 것을 보였으나 안정적인 3D지각이 되지 않았을 때의 시청각도에서는 거리에 따른 피로도의 차이가 없었다. 이러한 결과는 무안경식 3D 디스플레이와 i3D 시스템 개발에 있어 최적의 사용자 경험을 위한 중요한 자료이다. Observers usually experience visual fatigue when they watch contents displayed on 3D display. There has been various research on visual fatigue incurred in stereoscopic displays that use 3D glasses, but relatively less studies have been done in the area of autostereoscopic displays. i3D system refers to interactive 3D system that makes it possible for users to interact with contents using their hands. Current research measured visual fatigue that users experience from i3D under various visual environments. We examined the effects of viewing distance, disparities and visual orientation on visual fatigue in i3D. The results indicated that visual fatigue decreased with longer distance and smaller disparity. Visual fatigue increased with angle when 3D fusion was unstable. In addition, there was an interaction effect between angle and distance in which visual fatigue increased with distance under stable 3D fusion but there was no difference in visual fatigue as a function of distance when 3D fusion was unstable. These results would be importantly used to develop autostereoscopic displays that minimize visual fatigue.

다크 모드에서 모바일 시각정보요소 카드의 시각적 인지도와 피로도 연구

황승현,이현진 한국색채학회 2022 한국색채학회 논문집 Vol.36 No.1

This study set out to analyze colors of high visual recognition and low visual fatigue at the tone level and their saturation scope in a mobile interface card fit for the dark mode in low illuminance, as well as propose a color scheme. For these purposes, the study analyzed color palettes for the dark mode in the Android system, then we tested color scheme samples of card elements in app layout to collect factors affecting visual recognition and fatigue. The survey answers with Likert and ordinal scales of the test were analyzed to prove study hypotheses. The findings show that the tone levels and colors had an effect on the visual recognition and fatigue items except for the items of color understanding and the items of composition understanding based on Likert scale survey. The analysis results identified a couple of colors of high visual recognition including yellow at the tone levels of 50, 100, and 300, blue at the tone levels of 50 and 300, and purple at the tone level of 100. Blue had low visual fatigue, and so did teal and purple at the tone level of 50. Both blue and purple had a low level of ocular discomfort like teal, which recorded lower visual fatigue than them. The analysis results identified purple and teal at the tone level of 100, and purple was found in all the items of visual fatigue. Yellow and teal were analyzed as the colors with the low visual fatigue at the tone level of 300. Yellow had a low level of ocular discomfort like blue, which recorded a lower level of ocular discomfort than yellow. Blue and yellow of high visual recognition were high in saturation, and teal and purple of low visual fatigue were lower in saturation than blue and yellow.

Canonical Correlation of 3D Visual Fatigue between Subjective and Physiological Measures

Myeung Ju Won,Sang In Park,Mincheol Whang 대한인간공학회 2012 大韓人間工學會誌 Vol.31 No.6

Objective: The aim of this study was to investigate the correlation between 3D visual fatigue and physiological measures by canonical correlation analysis enabling to categorical correlation. Background: Few studies have been conducted to investigate the physiological mechanism underlying the visual fatigue caused by processing 3D information which may make the cognitive mechanism overloaded. However, even the previous studies lack validation in terms of the correlation between physiological variables and the visual fatigue. Method: 9 Female and 6 male subjects with a mean age of 22.53±2.55 voluntarily participated in this experiment. All participants were asked to report how they felt about their health sate at after viewing 3D. In addition, Low & Hybrid measurement test(Event Related Potential, Steady-state Visual Evoked Potential) and for evaluating cognitive fatigue before and after viewing 3D were performed. The physiological signal were measured with subjective fatigue evaluation before and after in watching the 3D content. For this study suggesting categorical correlation, all measures were categorized into three sets such as included Visual Fatigue set(response time, subjective evaluation), Autonomic Nervous System set(PPG frequency, PPG amplitude, HF/LF ratio), Central Nervous System set(ERP amplitude P4, O1, O2, ERP latency P4, O1, O2, SSVEP S/N ratio P4, O1, O2). Then the correlation of three variables sets, canonical correlation analysis was conducted. Results: The results showed a significant correlation between visual fatigue and physiological measures. However, different variables of visual fatigue were highly correlated to respective HF/LF ratio and to ERP latency(O2). Conclusion: Response time was highly correlated to ERP latency(O2) while the subjective evaluation was to HF/LF ratio. Application: This study may provide the most significant variables for the quantitative evaluation of visual fatigue using HF/LF ratio and ERP latency based human performance and subjective fatigue.

Effects of display curvature, display zone, and task duration on legibility and visual fatigue during visual search task

Park, Sungryul,Choi, Donghee,Yi, Jihhyeon,Lee, Songil,Lee, Ja Eun,Choi, Byeonghwa,Lee, Seungbae,Kyung, Gyouhyung Elsevier 2017 Applied ergonomics Vol.60 No.-

<P><B>Abstract</B></P> <P>This study examined the effects of display curvature (400, 600, 1200 mm, and flat), display zone (5 zones), and task duration (15 and 30 min) on legibility and visual fatigue. Each participant completed two 15-min visual search task sets at each curvature setting. The 600-mm and 1200-mm settings yielded better results than the flat setting in terms of legibility and perceived visual fatigue. Relative to the corresponding centre zone, the outermost zones of the 1200-mm and flat settings showed a decrease of 8%–37% in legibility, whereas those of the flat setting showed an increase of 26%–45% in perceived visual fatigue. Across curvatures, legibility decreased by 2%–8%, whereas perceived visual fatigue increased by 22% during the second task set. The two task sets induced an increase of 102% in the eye complaint score and a decrease of 0.3 Hz in the critical fusion frequency, both of which indicated an increase in visual fatigue. In summary, a curvature of around 600 mm, central display zones, and frequent breaks are recommended to improve legibility and reduce visual fatigue.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Curvatures of 600 mm and 1200 mm were more legible and less visually fatiguing than a flat display. </LI> <LI> Legibility decreased by 8%–37% in the outermost zones of the 1200-mm and flat settings. </LI> <LI> Visual fatigue increased by 26%–45% in the outermost zones of the flat setting. </LI> <LI> A 30-min visual search task induced visual fatigue. </LI> <LI> Use of ∼600 mm curvature, avoiding the outer zones, and frequent breaks are advised for VDT tasks. </LI> </UL> </P>

Head-Mounted Display(HMD) 시청 환경에서 양안 밝기 차이에 따른 피로도 - 감각성 우세안을 중심으로

김효선(Kim, Hyosun),서영준(Seo, Young-Jun),조성찬(Jo, Sung-Chan) 한국색채학회 2021 한국색채학회 논문집 Vol.35 No.2

Since both stereoscopic devices and Head-Mounted Displays (HMDs) use the diplopic projection which the separate images are presented on the left- and right-eye, it is revealed that the difference of binocular images caused the visual fatigue. In addition, the interocular imbalance, especially the sensory eye dominance, can also be connected with the visual fatigue by the photometric asymmetry of the binocular images. The purpose of this study is to investigate how the brightness asymmetry between the binocular images affect the visual fatigue and to explore how the sensory dominance affects visual fatigue. Wearing HMDs, participants were asked to view binocular images: one had 100% brightness, the other 50~90% brightness. They evaluated the visual fatigue on a 7-point Likert scale. As the result, an increase in brightness asymmetry between viewers’ left-eye and right-eye increased the visual fatigue scores. The relationship between the sensory dominance and the visual fatigue by the brightness asymmetry was different depending on the type of image. The visual fatigue increased as the brightness of images, which entering to the sensory dominant eye, decreased in the case of the black-and-white images. On the contrary, the visual fatigue was not changed in the case of color images in the same condition. This meant that the brightness contrast and color contrast had different effect on the visual fatigue. Overall, we suggest that the brightness asymmetry of less than 30% is suitable for a comfortable and positive viewing experience.

편광식 3D 디스플레이를 위한 상대적 시차, 시청 거리, 시청 방위에서의 시각피로 최소화 기준 제안

박종진 ( Jong Jin Park ),김신우 ( Shin Woo Kim ),이형철 ( Hyung Chul Li ) 한국감성과학회 2016 감성과학 Vol.19 No.1

입체 시각 피로는 3D 영상의 확산을 방해하는 가장 주된 요인으로 알려져 있다. 입체 시각 피로는 수렴과 조절의 불일치에 의하여 유발되는 것으로, 이 현상은 양안 시차를 포함하는 영상을 3D 디스플레이로 제시하는 경우 자극에 의하여 유발된 수렴 거리가 물리적인 조절 거리와 불일치하여 발생한다. 이는 실감을 증진시키기 위하여 입체 자극을 사용하는 경우 언제나 입체 시각 피로를 유발할 가능성이 있음을 의미한다. 따라서 입체 시각 피로를 감소시키기 위하여 직접적인 원인을 제거하려는 노력뿐만 아니라 이를 간접적으로 감소시키기 위한 노력 역시 필요하다. 이런관점에서 본 연구는 입체 시각 피로에 영향을 미칠 가능성이 높은 상대적 시차, 시청 거리, 시청 방위 요인이 주관적입체 시각 피로에 미치는 영향을 측정하고 입체 시각 피로를 최소화하기 위한 각 요인의 수준을 알아보고자 하였다. 그 결과 참가자들이 입체 시각 피로를 보고하는 경우는 상대적 시차의 교차 시차 크기가 7분 22초를 넘어설 때, 그리고 수직 시야각이 15도 보다 클 때라는 것을 확인하였다. 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.

Visual Discomfort and Visual Fatigue

Jungmin Han,Seon Hee Bae,Hyeon-Jeong Suk 대한인간공학회 2017 大韓人間工學會誌 Vol.36 No.4

Objective: This study aims to evaluate visual discomfort and visual fatigue caused by watching HMD and smartphones by conducting both subjective and objective measure. Background: With the rapid development of mobile Head-Mounted Display (HMD), the problem of visual discomfort and visual fatigue caused by watching Virtual Reality (VR) contents became a crucial concern for consumers and manufacturers, especially given that the casing of mobile HMD keeps the phone at a specified distance from the lenses that is close to the eyes. Method: Two smartphones were chosen for a preliminary study: LG G5 and Galaxy S7. As for a main study, iPhone 6S and Galaxy S7 were used. After being exposed to the selected clips, participants were asked to answer Simulator Sickness Questionnaire (SSQ) and went through optometric tests that measure tear break-up time, spherical equivalent, and contrast sensitivity. Results: The subjective assessments indicate that HMD causes more visual discomfort compared to watching a smartphone. Furthermore, the experimental result confirms that watching a HMD causes more eye dryness compared to smartphones. Conclusion: The result of the study compared visual discomfort and visual fatigue of two different displays, HMD and smartphone, and confirmed that watching HMD causes more visual discomfort and visual fatigue. Application: Ultimately, this study could help manufacturers understand the strengths and weaknesses of different display forms, providing guidance for an effective application of HMD.

EEG 생체신호 기반 3D 시각피로 측정방법에 대한 타당화 연구

이형철 ( Hyung Chul Li ),문경애 ( Kyung Ae Moon ) 한국감성과학회 2012 감성과학 Vol.15 No.1

최근의 디스플레이 기술은 2차원 디스플레이에 제시된 영상으로부터 3차원 깊이감을 지각하는 것을 가능하게 하였다. 이런은 디스플레이와 콘텐츠 기술의 발전에도 불구하고, 사용자는 실생활에서 경험하지 않는 시각피로의 문제를 경험하는데, 이 문제를 해결하기 위해서는 시각피로를 안정적이고 타당하게 측정하는 것이 필요하다. 본 연구의 목적은 EEG(Electroencephalography)신호에 기반한 시각피로 측정의 프로토콜을 개발하고 타당성을 검증하는 것이었다. ERP(Event related potential) 성분 중에서 시각피로를 반영하는 성분을 찾아내기 위해 2D 조건과 3D 조건에서 탐색적 실험을 수행하였고, 탐색적 실험에서 발견된 ERP 성분이 양안시차의 차이 에 따라 상이한 특성을 보이는지 검증하기 위하여 확인적 실험을 수행하였다. 실험결과, Cz와 Pz 영역에서 P3성분의 정점 강도가 2D 조건보다는 3D 조건에서 감소하였으며, 양안시차가 증가할수록 일관되게 P3 성분의 강도가 통계적으로 유의하게 감소하는 것을 확인하였다. 양안시차가 증가함에 따라서 주관적인 시각피로가 통계적으로 유의하게 증가함을 검증하였는데, 이 실험결과는 Cz와 Pz 영역에서의 P3 성분의 정점 강도가 3D 시각피로에 대한 인덱스로 사용할 수 있음을 시사한다. 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.

Digital Devices and Visual Fatigue - Development of Low-Cost Measurement Methodology

( D. Bhanu Priya ),( Murali Subramaniyam ) 한국감성과학회 2021 추계학술대회 Vol.2021 No.0

PURPOSE: The digital device's introduction was a revolutionary moment in human history. As a result, eye strain due to digital devices (smartphones) has become more prevalent among all age groups, precisely due to prolonged usage. Various physiological indicators (blink rate and pupil dilation) are utilized to identify the state of the eye. This study aims to measure the visual fatigue induced due to smartphones with the change in blink rate and pupil dilation among adolescents. METHODS: A systematic literature search was conducted to identify developments and various techniques available to measure visual fatigue. Then this study proposed a low-cost experimental setup for measuring the change in blink rate and pupil dilation due to prolonged smartphone utilization. Finally, understand the correlation between the factors associated with visual fatigue. RESULTS: The existing developments and techniques were analyzed, and a new methodology was proposed. The proposed algorithm performs detection of facial landmarks, localization of eyes, and compute blink rate in video streaming. CONCLUSION: The proposed eye blink rate and pupil dilation detection algorithm is precise, easy to implement, efficient, cost-effective, and fast. In future, the proposed algorithm should be validated with a gold standard for measuring visual activity.

Digital Devices and Visual Fatigue - Development of Low-Cost Measurement Methodology

( D. Bhanu Priya ),( Murali Subramaniyam ) 한국감성과학회 2021 한국감성과학회 국제학술대회(ICES) Vol.2021 No.-

PURPOSE: The digital device's introduction was a revolutionary moment in human history. As a result, eye strain due to digital devices (smartphones) has become more prevalent among all age groups, precisely due to prolonged usage. Various physiological indicators (blink rate and pupil dilation) are utilized to identify the state of the eye. This study aims to measure the visual fatigue induced due to smartphones with the change in blink rate and pupil dilation among adolescents. METHODS: A systematic literature search was conducted to identify developments and various techniques available to measure visual fatigue. Then this study proposed a low-cost experimental setup for measuring the change in blink rate and pupil dilation due to prolonged smartphone utilization. Finally, understand the correlation between the factors associated with visual fatigue. RESULTS: The existing developments and techniques were analyzed, and a new methodology was proposed. The proposed algorithm performs detection of facial landmarks, localization of eyes, and compute blink rate in video streaming. CONCLUSION: The proposed eye blink rate and pupil dilation detection algorithm is precise, easy to implement, efficient, cost-effective, and fast. In future, the proposed algorithm should be validated with a gold standard for measuring visual activity.