Engineering data compendium. Human perception and performance. User's guide

The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design and military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from the existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by systems designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is the first volume, the User's Guide, containing a description of the program and instructions for its use

Visualeyes 2020: a software suite to integrate instrumentation to study the near triad of vergence

A complete instrumentation suite has been constructed for use in a randomized clinical trial to be funded from the National Institute of Health and study the underlying potential mechanism(s) of vision therapy. This suite is designed to track rotation of each eye (vergence) as well as measure the lens power of the eye\u27s lens (accommodation). The system is designed to dissect the near triad which is composed of the pupil constriction, vergence and accommodation. The visual targets are programmed to be shown on two sets of computer screens which allowed vergence, accommodation and proximal vergence cues to be presented in isolation or in combination to study the Maddox components of vergence. This instrument uses FDA approved devices for subject safety. In our custom LabView based software, the Haploscope is able to generate ocular stimuli from programmed scripts, record data, as well as perform other various experimental requirements. Post processing is done in a MATLAB GUI environment. The results support that vergence responses can be studied using one to several visual cues

Binocular integration using stereo motion cues to drive behavior in mice

The visual system presents an opportunity to study how two signals converge to generate a novel representation of the world: depth. The slight difference in positions between the two eyes means that different images are encoded by the left and right eyes by generating disparity signals. Another way to generate depth signals is by presenting different motion signals to the two eyes. Even though the binocular visual system has been studied for a long time, the mechanisms behind binocular integration when objects move in depth are largely unknown. In this dissertation, I demonstrate a new model for studying motion-in-depth signals using mice. Mice are an attractive animal to study the binocular visual system not only because they share common visual pathway as primates and other mammals, but also because there are genetic tools that can be used to study the underlying circuitry for binocular integration during motion-in-depth cues. Thus far there have been very few studies regarding binocularity in mice. This dissertation will focus on the behavioral output during stereoscopic motion-in-depth signals in mice and investigate visual areas involved in these behaviors. In the first section, I investigate whether mice discriminate motion-in-depth signals like primates, using disparity and motion signals presented to each eye. I find that mice are able to discriminate towards and away stimuli and that the binocular neurons in the visual cortex were critical for the computation of this signal. In the second section we measured optokinetic eye movement generated by motion-in-depth stimulus. I found that vergence eye movement in mice is driven primarily by the motion signals presented in each eye. This phenomenon can be explained largely by the summation of monocular motor signals of the two eyes that happens subcortically. These two experiments both show clear behavioral output that can be only generated when presented with binocular motion-in-depth signals. I find both cortical and subcortical components of binocular integration that are responsible for the generation of these behavior outputs which demonstrates the complicated nature of binocular integration associated with motion-in-depth signals. My work in this dissertation provides the foundation for studying binocular integration in rodentsNeuroscienc

Visual discomfort whilst viewing 3D stereoscopic stimuli

3D stereoscopic technology intensifies and heightens the viewer s experience by adding an extra dimension to the viewing of visual content. However, with expansion of this technology to the commercial market concerns have been expressed about the potential negative effects on the visual system, producing viewer discomfort. The visual stimulus provided by a 3D stereoscopic display differs from that of the real world, and so it is important to understand whether these differences may pose a health hazard. The aim of this thesis is to investigate the effect of 3D stereoscopic stimulation on visual discomfort. To that end, four experimental studies were conducted. In the first study two hypotheses were tested. The first hypothesis was that the viewing of 3D stereoscopic stimuli, which are located geometrically beyond the screen on which the images are displayed, would induce adaptation changes in the resting position of the eyes (exophoric heterophoria changes). The second hypothesis was that participants whose heterophoria changed as a consequence of adaptation during the viewing of the stereoscopic stimuli would experience less visual discomfort than those people whose heterophoria did not adapt. In the experiment an increase of visual discomfort change in the 3D condition in comparison with the 2D condition was found. Also, there were statistically significant changes in heterophoria under 3D conditions as compared with 2D conditions. However, there was appreciable variability in the magnitude of this adaptation among individuals, and no correlation between the amount of heterophoria change and visual discomfort change was observed. In the second experiment the two hypotheses tested were based on the vergence-accommodation mismatch theory, and the visual-vestibular mismatch theory. The vergence-accommodation mismatch theory predicts that a greater mismatch between the stimuli to accommodation and to vergence would produce greater symptoms in visual discomfort when viewing in 3D conditions than when viewing in 2D conditions. An increase of visual discomfort change in the 3D condition in comparison with the 2D condition was indeed found; however the magnitude of visual discomfort reported did not correlate with the mismatch present during the watching of 3D stereoscopic stimuli. The visual-vestibular mismatch theory predicts that viewing a stimulus stereoscopically will produce a greater sense of vection than viewing it in 2D. This will increase the conflict between the signals from the visual and vestibular systems, producing greater VIMS (Visually- Induced Motion Sickness) symptoms. Participants did indeed report an increase in motion sickness symptoms in the 3D condition. Furthermore, participants with closer seating positions reported more VIMS than participants sitting farther away whilst viewing 3D stimuli. This suggests that the amount of visual field stimulated during 3D presentation affects VIMS, and is an important factor in terms of viewing comfort. In the study more younger viewers (21 to 39 years old) than older viewers (40 years old and older) reported a greater change in visual discomfort during the 3D condition than the 2D condition. This suggests that the visual system s response to a stimulus, rather than the stimulus itself, is a reason for discomfort. No influence of gender on viewing comfort was found. In the next experiment participants fusion capability, as measured by their fusional reserves, was examined to determine whether this component has an impact on reported discomfort during the watching of movies in the 3D condition versus the 2D condition. It was hypothesised that participants with limited fusional range would experience more visual discomfort than participants with a wide fusion range. The hypothesis was confirmed but only in the case of convergent and not divergent eye movement. This observation illustrates that participants capability to convergence has a significant impact on visual comfort. The aim of the last experiment was to examine responses of the accommodation system to changes in 3D stimulus position and to determine whether discrepancies in these responses (i.e. accommodation overshoot, accommodation undershoot) could account for visual discomfort experienced during 3D stereoscopic viewing. It was found that accommodation discrepancy was larger for perceived forwards movement than for perceived backwards movement. The discrepancy was slightly higher in the group susceptible to visual discomfort than in the group not susceptible to visual discomfort, but this difference was not statistically significant. When considering the research findings as a whole it was apparent that not all participants experienced more discomfort whilst watching 3D stereoscopic stimuli than whilst watching 2D stimuli. More visual discomfort in the 3D condition than in the 2D condition was reported by 35% of the participants, whilst 24% of the participants reported more headaches and 17% of the participants reported more VIMS. The research indicates that multiple causative factors have an impact on reported symptoms. The analysis of the data suggests that discomfort experienced by people during 3D stereoscopic stimulation may reveal binocular vision problems. This observation suggests that 3D technology could be used as a screening method to diagnose un-treated binocular vision disorder. Additionally, this work shows that 3D stereoscopic technology can be easily adopted to binocular vision measurement. The conclusion of this thesis is that many people do not suffer adverse symptoms when viewing 3D stereoscopic displays, but that if adverse symptoms are present they can be caused either by the conflict in the stimulus, or by the heightened experience of self-motion which leads to Visually-Induced Motion Sickness (VIMS)

Perceived Acceleration in Stereoscopic Animation

In stereoscopic media, a sensation of depth is produced through the differences of images presented to the left and the right eyes. These differences are a result of binocular parallax caused by the separation of the cameras used to capture the scene. Creators of stereoscopic media face the challenge of producing compelling depth while restricting the amount of parallax to a comfortable range. Control of camera separation is a key manipulation to control parallax. Sometimes, stereoscopic warping is used in post-production process to selectively increase or decrease depth in certain regions of the image. However, mismatches between camera geometry and natural stereoscopic geometry can theoretically produce nonlinear distortions of perceived space. The relative expansion or compression of the stereoscopic space, in theory, should affect the perceived acceleration of objects moving through that space. This thesis suggests that viewers are tolerant of effects of distortions when perceiving acceleration in a stereoscopic scene