scholarly journals The Impact of Dynamic Convergence on the Human Visual System in Head Mounted Displays

2021 ◽  
Author(s):  
◽  
Ryan Sumner
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Statistical Significance ◽  
Depth Range ◽  
Binocular Fusion ◽  
Virtual Objects ◽  
Beneficial Effects ◽  
Mixed Response ◽  
Head Mounted Displays ◽  
The Impact

<p>The Accommodation-Vergence Conflict (AVC) is a phenomenon in the area of Head-Mounted Displays (HMDs) and one of the key issues hindering the popularity of HMDs largely due to it causing a large number of users to suffer from simulator sickness. There have been several proposed solutions developed by previous researchers, including the introduction of 'Dynamic Convergence' (DC) which, addresses the AVC problem in terms of the vergence depth cue. DC also helps in the performance of binocular fusion when viewing at a close vergence depth. As of yet however, DC has not undergone detailed testing for a number of important cases, which limits the amount of data that has been collected on DC's interaction with the human visual system. In addition, no DC research as of yet has dealt with the effect of a change in vergence depth, and how that change in the vergence angle of the focal plane would effect a user.  Thus, this thesis adds to the growing body of research and knowledge in this field by implementing DC with the addition of some transitions between a change in vergence depth. This is done within the Unity3D game engine in order to further investigate the impact of DC with regard to viewing close virtual objects on HMDs through a number of cases. The added transitions are also tested to see if they have any beneficial effects for users when the vergence angle changes. The investigation is centered around a perception based performance/appreciation-oriented visual study whereby participants were asked about their ability to perform binocular fusion on close virtual objects that were either stationary or moving and varying distances and speeds. Participants were also asked to report any symptoms of discomfort.  The research has adopted a mixed methodology experimental approach by conducting user experiments and surveys, before analysing the results through both in-depth quantitative statistical analysis and a variety of qualitative statistical techniques in order to measure and investigate the scale of the problem associated with the impact of DC on the human visual system in HMDs when viewing close virtual objects.  From the investigation it was confirmed that the approximate effective vergence depth range for DC was 0.3m or less, with statistical significance confirmed at the 0.15m distance. Participants reported having an easier time performing binocular fusion at these closer distances while DC was enabled. As a result of this, the majority of cases and scenarios did not report any significant negative responses in terms of discomfort symptoms. However attempts at improving DC with a transition between vergence depths were met with a mixed response from participants. While the need of a transition way be dependent on the user, there still exists some demand for one, thus it should still be available as an option.</p>

scholarly journals The Impact of Dynamic Convergence on the Human Visual System in Head Mounted Displays

2021 ◽  
Author(s):  
◽  
Ryan Sumner
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Statistical Significance ◽  
Depth Range ◽  
Binocular Fusion ◽  
Virtual Objects ◽  
Beneficial Effects ◽  
Mixed Response ◽  
Head Mounted Displays ◽  
The Impact

<p>The Accommodation-Vergence Conflict (AVC) is a phenomenon in the area of Head-Mounted Displays (HMDs) and one of the key issues hindering the popularity of HMDs largely due to it causing a large number of users to suffer from simulator sickness. There have been several proposed solutions developed by previous researchers, including the introduction of 'Dynamic Convergence' (DC) which, addresses the AVC problem in terms of the vergence depth cue. DC also helps in the performance of binocular fusion when viewing at a close vergence depth. As of yet however, DC has not undergone detailed testing for a number of important cases, which limits the amount of data that has been collected on DC's interaction with the human visual system. In addition, no DC research as of yet has dealt with the effect of a change in vergence depth, and how that change in the vergence angle of the focal plane would effect a user.  Thus, this thesis adds to the growing body of research and knowledge in this field by implementing DC with the addition of some transitions between a change in vergence depth. This is done within the Unity3D game engine in order to further investigate the impact of DC with regard to viewing close virtual objects on HMDs through a number of cases. The added transitions are also tested to see if they have any beneficial effects for users when the vergence angle changes. The investigation is centered around a perception based performance/appreciation-oriented visual study whereby participants were asked about their ability to perform binocular fusion on close virtual objects that were either stationary or moving and varying distances and speeds. Participants were also asked to report any symptoms of discomfort.  The research has adopted a mixed methodology experimental approach by conducting user experiments and surveys, before analysing the results through both in-depth quantitative statistical analysis and a variety of qualitative statistical techniques in order to measure and investigate the scale of the problem associated with the impact of DC on the human visual system in HMDs when viewing close virtual objects.  From the investigation it was confirmed that the approximate effective vergence depth range for DC was 0.3m or less, with statistical significance confirmed at the 0.15m distance. Participants reported having an easier time performing binocular fusion at these closer distances while DC was enabled. As a result of this, the majority of cases and scenarios did not report any significant negative responses in terms of discomfort symptoms. However attempts at improving DC with a transition between vergence depths were met with a mixed response from participants. While the need of a transition way be dependent on the user, there still exists some demand for one, thus it should still be available as an option.</p>

scholarly journals ОСОБЛИВОСТІ ФУНКЦІОНУВАННЯ ЗОРОВО СИСТЕМИ У КОРИСТУВАЧІВ КОМП’ЮТЕРІВ

2015 ◽  
Author(s):  
N. B. Behosh ◽  
I. B. Chornomydz ◽  
O. Ya. Zyatkovska
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Computer Users ◽  
Visual Features ◽  
System A ◽  
The Impact ◽  
Flow Of Information ◽  
Visual Apparatus

The article adduces the various aspects of the impact of a computer monitor on the functioning of the human visual system. A significant flow of information which daily receives visual apparatus person with computer screens accompanied not only asthenopia but also objective changes of the visual system. There was analysed the visual features and the factors that determined the occurrence of changes in the refractive computer users.

2D and 3D Visual Attention for Computer Vision

2016 ◽  
pp. 1-44
Author(s):  
Vincent Ricordel ◽  
Junle Wang ◽  
Matthieu Perreira Da Silva ◽  
Patrick Le Callet
Keyword(s):  
Computer Vision ◽  
Visual Perception ◽  
Visual Attention ◽  
Visual System ◽  
Computational Modeling ◽  
Depth Perception ◽  
Human Visual System ◽  
Visual Importance ◽  
2D And 3D ◽  
The Impact

Visual attention is one of the most important mechanisms deployed in the human visual system (HVS) to reduce the amount of information that our brain needs to process. An increasing amount of efforts has been dedicated to the study of visual attention, and this chapter proposes to clarify the advances achieved in computational modeling of visual attention. First the concepts of visual attention, including the links between visual salience and visual importance, are detailed. The main characteristics of the HVS involved in the process of visual perception are also explained. Next we focus on eye-tracking, because of its role in the evaluation of the performance of the models. A complete state of the art in computational modeling of visual attention is then presented. The research works that extend some visual attention models to 3D by taking into account of the impact of depth perception are finally explained and compared.

2D and 3D Visual Attention for Computer Vision

3D Printing ◽  
2017 ◽  
pp. 75-118
Author(s):  
Vincent Ricordel ◽  
Junle Wang ◽  
Matthieu Perreira Da Silva ◽  
Patrick Le Callet
Keyword(s):  
Computer Vision ◽  
Visual Perception ◽  
Visual Attention ◽  
Visual System ◽  
Computational Modeling ◽  
Depth Perception ◽  
Human Visual System ◽  
Visual Importance ◽  
2D And 3D ◽  
The Impact

Visual attention is one of the most important mechanisms deployed in the human visual system (HVS) to reduce the amount of information that our brain needs to process. An increasing amount of efforts has been dedicated to the study of visual attention, and this chapter proposes to clarify the advances achieved in computational modeling of visual attention. First the concepts of visual attention, including the links between visual salience and visual importance, are detailed. The main characteristics of the HVS involved in the process of visual perception are also explained. Next we focus on eye-tracking, because of its role in the evaluation of the performance of the models. A complete state of the art in computational modeling of visual attention is then presented. The research works that extend some visual attention models to 3D by taking into account of the impact of depth perception are finally explained and compared.

scholarly journals ‘Proto-rivalry’: how the binocular brain identifies gloss

2016 ◽  
Vol 283 (1830) ◽  
pp. 20160383 ◽  
Author(s):  
Alexander A. Muryy ◽  
Roland W. Fleming ◽  
Andrew E. Welchman
Keyword(s):  
Visual Cortex ◽  
Machine Vision ◽  
Visual System ◽  
Human Visual System ◽  
Binocular Fusion ◽  
Low Level ◽  
Material Appearance

Visually identifying glossy surfaces can be crucial for survival (e.g. ice patches on a road), yet estimating gloss is computationally challenging for both human and machine vision. Here, we demonstrate that human gloss perception exploits some surprisingly simple binocular fusion signals, which are likely available early in the visual cortex. In particular, we show that the unusual disparity gradients and vertical offsets produced by reflections create distinctive ‘proto-rivalrous’ (barely fusible) image regions that are a critical indicator of gloss. We find that manipulating the gradients and vertical components of binocular disparities yields predictable changes in material appearance. Removing or occluding proto-rivalrous signals makes surfaces look matte, while artificially adding such signals to images makes them appear glossy. This suggests that the human visual system has internalized the idiosyncratic binocular fusion characteristics of glossy surfaces, providing a straightforward means of estimating surface attributes using low-level image signals.

scholarly journals Design of monocular head-mounted displays, with a case study on fire-fighting

2007 ◽  
Vol 221 (12) ◽  
pp. 1729-1743 ◽  
Author(s):  
J Wilson ◽  
P Wright
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Optical Design ◽  
Physical World ◽  
Design Guidelines ◽  
Fire Fighting ◽  
Joint Torque ◽  
Head Mounted Displays ◽  
Context Specific

The paper presents a design methodology and a case study for monocular head-mounted displays (HMDs), wherein a user can simultaneously and easily see the physical world by looking through and/or around the display. The design approach is user-focused because of the complexity of the human visual system, and because HMDs are very task, user, and context specific. A literature review of factors related to HMD design is given. This includes considerations for basic optical design, the human visual system, and head and neck biomechanics. General HMD design guidelines are given based on these considerations. For the specific case study on fire-fighting, it is recommended that the HMD be mounted at 15° to 45° below the Frankfurt plane, with a 15° to 40° field of view. A resolution of 20–60 px/deg should be focused at 1 m or farther. The neck joint torque due to the HMD should not exceed about 1 Nm. This equates to a typical maximum weight of 0.5 to 1 kg depending on the mounting location.

scholarly journals Would Gaze-Contingent Rendering Improve Depth Perception in Virtual and Augmented Reality?

2019 ◽  
Author(s):  
Paul Linton
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
Depth Perception ◽  
Physical Distance ◽  
Virtual Objects ◽  
Optical Distance ◽  
Head Mounted Displays ◽  
Virtual And Augmented Reality ◽  
Perspective Distortions ◽  
The Impact

Near distances are overestimated in virtual reality, and far distances are underestimated, but an explanation for these distortions remains elusive. One potential concern is that whilst the eye rotates to look at the virtual scene, the virtual cameras remain static. Could using eye-tracking to change the perspective of the virtual cameras as the eye rotates improve depth perception in virtual reality? This paper identifies 14 distinct perspective distortions that could in theory occur from keeping the virtual cameras fixed whilst the eye rotates in the context of near-eye displays. However, the impact of eye movements on the displayed image depends on the optical, rather than physical, distance of the display. Since the optical distance of most head-mounted displays is over 1m, most of these distortions will have only a negligible effect. The exception are ‘gaze-contingent disparities’, which will leave near virtual objects looking displaced from physical objects that are meant to be at the same distance in augmented reality.

scholarly journals Glycyrrhizin Attenuates Portal Hypertension and Collateral Shunting via Inhibition of Extrahepatic Angiogenesis in Cirrhotic Rats

2021 ◽  
Vol 22 (14) ◽  
pp. 7662
Author(s):  
Chon Kit Pun ◽  
Hui-Chun Huang ◽  
Ching-Chih Chang ◽  
Chiao-Lin Chuang ◽  
Chun-Hsien Yen ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Portal Hypertension ◽  
Liver Fibrosis ◽  
Statistical Significance ◽  
Portal Pressure ◽  
Sham Operation ◽  
Sprague Dawley ◽  
Beneficial Effects ◽  
Duct Ligation ◽  
The Impact

Portal hypertension develops along with liver cirrhosis then induces the formation of portal-systemic collaterals and lethal complications. Extrahepatic angiogenesis plays an important role. Glycyrrhizin has been found to exhibit anti-angiogenic features, which leads to its extensive use. However, the relevant effects of glycyrrhizin on liver cirrhosis and portal hypertension have not been evaluated. This study thus aimed to investigate the impact of glycyrrhizin on portal hypertension-related derangements in cirrhotic rats. Male Sprague-Dawley rats received bile duct ligation (BDL) to induce cirrhosis or sham operation as control. The rats were subdivided to receive glycyrrhizin (150 mg/kg/day, oral gavage) or vehicle beginning on the 15th day post operation, when BDL-induced liver fibrosis developed. The effects of glycyrrhizin were determined on the 28th day, the typical timing of BDL-induced cirrhosis. Glycyrrhizin significantly reduced portal pressure (p = 0.004). The splanchnic inflow as measured by superior mesenteric arterial flow decreased by 22% (p = 0.029). The portal-systemic collateral shunting degree reduced by 30% (p = 0.024). The mesenteric angiogenesis and phospho-VEGFR2 protein expression were also downregulated (p = 0.038 and 0.031, respectively). Glycyrrhizin did not significantly influence the liver biochemistry data. Although glycyrrhizin tended to reverse liver fibrosis, statistical significance was not reached (p = 0.069). Consistently, hepatic inflow from portal side, hepatic vascular resistance, and liver fibrosis-related protein expressions were not affected. Glycyrrhizin treatment at the stage of hepatic fibrosis still effectively attenuated portal hypertension and portosystemic collateral shunting. These beneficial effects were attributed to, at least in part, the suppression of mesenteric angiogenesis by VEGF signaling pathway downregulation.

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