Journal articles on the topic 'Stereoscopic vision, depth'
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1
Uomori, Kenya, and Mitsuho Yamada. "Special Edition. Human Vision. Stereoscopic Vision and Depth Perception." Journal of the Institute of Television Engineers of Japan 48, no. 12 (1994): 1502–8. http://dx.doi.org/10.3169/itej1978.48.1502.
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Ninio, J. "Curvature Biases in Stereoscopic Vision." Perception 26, no. 1_suppl (August 1997): 287. http://dx.doi.org/10.1068/v970154.
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The reliability of in-depth curvature judgements for linear elements was studied with stereograms that contained two linear targets and a background representing a hemisphere. The targets were arcs facing to the left or to the right, like parentheses. Some formed binocular pairs with (type 1) or without (type 2) in-depth curvature. The others were monocular (type 3). The hemisphere in the background was generated by a random curve (Ninio, 1981 Perception10 403 – 410); it was either concave (hollow) or convex. The arcs had their binocular centre in the plane of the centre of the hemisphere. Each stereogram contained a type 1, and either a type 2 or a type 3 target. Subjects had to judge the hemisphere curvature, then the in-depth curvature of the targets in 32 different stereograms covering all curvature combinations. There were about 15% errors on type 1 targets, and 80% of these occurred when both the hemisphere and the target were convex, the target being perceived as concave, by transparency through the hemisphere. There were also about 15% errors on type 2 targets, but spread among all situations, the trend being to perceive them as slightly concave. The monocular stimuli (type 3) were judged to be frontoparallel in 70% of the cases. Otherwise, there was no directional bias except for monocular arcs on the nasal side, in conjunction with a concave background. Then, the perceived in-depth curvature was in the ‘generic’ direction predicted by associating the monocular arc in one image with a straight vertical segment in the other image.
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Bridge, Holly. "Effects of cortical damage on binocular depth perception." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1697 (June 19, 2016): 20150254. http://dx.doi.org/10.1098/rstb.2015.0254.
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Stereoscopic depth perception requires considerable neural computation, including the initial correspondence of the two retinal images, comparison across the local regions of the visual field and integration with other cues to depth. The most common cause for loss of stereoscopic vision is amblyopia, in which one eye has failed to form an adequate input to the visual cortex, usually due to strabismus (deviating eye) or anisometropia. However, the significant cortical processing required to produce the percept of depth means that, even when the retinal input is intact from both eyes, brain damage or dysfunction can interfere with stereoscopic vision. In this review, I examine the evidence for impairment of binocular vision and depth perception that can result from insults to the brain, including both discrete damage, temporal lobectomy and more systemic diseases such as posterior cortical atrophy. This article is part of the themed issue ‘Vision in our three-dimensional world’.
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Guan, Phillip, and Martin S. Banks. "Stereoscopic depth constancy." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1697 (June 19, 2016): 20150253. http://dx.doi.org/10.1098/rstb.2015.0253.
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Depth constancy is the ability to perceive a fixed depth interval in the world as constant despite changes in viewing distance and the spatial scale of depth variation. It is well known that the spatial frequency of depth variation has a large effect on threshold. In the first experiment, we determined that the visual system compensates for this differential sensitivity when the change in disparity is suprathreshold, thereby attaining constancy similar to contrast constancy in the luminance domain. In a second experiment, we examined the ability to perceive constant depth when the spatial frequency and viewing distance both changed. To attain constancy in this situation, the visual system has to estimate distance. We investigated this ability when vergence, accommodation and vertical disparity are all presented accurately and therefore provided veridical information about viewing distance. We found that constancy is nearly complete across changes in viewing distance. Depth constancy is most complete when the scale of the depth relief is constant in the world rather than when it is constant in angular units at the retina. These results bear on the efficacy of algorithms for creating stereo content. This article is part of the themed issue ‘Vision in our three-dimensional world’.
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Ludwig, Kai-Oliver, Heiko Neumann, and Bernd Neumann. "Local stereoscopic depth estimation." Image and Vision Computing 12, no. 1 (January 1994): 16–35. http://dx.doi.org/10.1016/0262-8856(94)90052-3.
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Tittle, James S., Michael W. Rouse, and Myron L. Braunstein. "Relationship of Static Stereoscopic Depth Perception to Performance with Dynamic Stereoscopic Displays." Proceedings of the Human Factors Society Annual Meeting 32, no. 19 (October 1988): 1439–42. http://dx.doi.org/10.1177/154193128803201928.
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Although most tasks performed by human observers that require accurate stereoscopic depth perception, such as working with tools, operating machinery, and controlling vehicles, involve dynamically changing disparities, classification of observers as having normal or deficient stereoscopic vision is currently based on performance with static stereoscopic displays. The present study compares the performance of subjects classified as deficient in static stereoscopic vision to a control group with normal stereoscopic vision in two experiments-one in which the disparities were constant during motion and one in which the disparities changed continuously. In the first experiment, subjects judged orientation in depth of a dihedral angle, with the apex pointed toward or away from them. The angle translated horizontally, leaving the disparities constant. When disparity and motion parallax were placed in conflict, subjects in the normal group almost always responded in accordance with disparity, whereas subjects in the deficient group responded in accordance with disparity at chance levels. In the second experiment, subjects were asked to judge the direction of rotation of a computer-generated cylinder. When dynamic occlusion and dynamic disparity indicated conflicting directions, performance of subjects in the normal and deficient groups did not differ significantly. When only dynamic disparity information was provided, most subjects classified as stereo deficient were able to judge the direction of rotation accurately. These results indicate that measures of stereoscopic vision that do not include changing disparities may not provide a complete evaluation of the ability of a human observer to perceive depth on the basis of disparity.
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Retno Wulandari, Lely. "A COMPREHENSIVE APPROACH INTO STEREOSCOPIC VISION." MNJ (Malang Neurology Journal) 8, no. 1 (January 1, 2022): 53–57. http://dx.doi.org/10.21776/ub.mnj.2022.008.01.11.
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Stereopsis (or stereoscopic) vision is the ability to see depth of perception, which is created by the difference in angle of view between both eyes. The first process is known as simultaneous perception. Objects will fall on each corresponding retina and there will be a process of fusion of the two images into one. Then, the brain initiates three-dimensional perception in visual cortex, creating stereoscopic vision. Stereoscopic vision will rapidly develop, especially at the age of 6-8 months of life. Stereoscopic is important in daily activities. There are many stereoacuity tests to evaluate stereoscopic vision. Stereoscopic examinations are based on the principle of haploscope, anaglyph, or polaroid vectograph. There are qualitative and quantitative examination methods to assess stereoscopic vision. Qualitative examinations such as Horizontal Lang Two Pencil test and Synoptophore. Quantitative examination including Contour stereopsis test and Clinical random dot stereopsis test. The inability of the eye to see stereoscopic can be called stereoblindness. This can be affected by amblyopia, decreased visual acuity, or the presence of ocular misalignment. Inability to achieve stereoscopic vision will impact an individual to perform some daily life activities, and lead to an increase in difficulty interacting in the world.
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Rose, David, Mark F. Bradshaw, and Paul B. Hibbard. "Attention Affects the Stereoscopic Depth Aftereffect." Perception 32, no. 5 (May 2003): 635–40. http://dx.doi.org/10.1068/p3324.
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‘Preattentive’ vision is typically considered to include several low-level processes, including the perception of depth from binocular disparity and motion parallax. However, doubt was cast on this model when it was shown that a secondary attentional task can modulate the motion aftereffect (Chaudhuri, 1990 Nature344 60–62). Here we investigate whether attention can also affect the depth aftereffect (Blakemore and Julesz, 1971 Science171 286–288). Subjects adapted to stationary or moving random-dot patterns segmented into depth planes while attention was manipulated with a secondary task (character processing at parametrically varied rates). We found that the duration of the depth aftereffect can be affected by attentional manipulations, and both its duration and that of the motion aftereffect varied with the difficulty of the secondary task. The results are discussed in the context of dynamic feedback models of vision, and support the penetrability of low-level sensory processes by attentional mechanisms.
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Takahashi, Satoshi. "Elucidation of the mechanism of stereoscopic insufficiency and mental and physical fatigue caused by near vision - research and development on recovery methods." Impact 2021, no. 5 (June 7, 2021): 78–79. http://dx.doi.org/10.21820/23987073.2021.5.78.
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Increased exposure to video terminal display (VDT) devices is part of 21st century life, but the consequences of this are myopia and abnormal binocular single vision, which present as mental and physical fatigue. A collaborative team is investigating the mechanism underlying abnormal binocular single vision and developing a methodology for recovery. Associate Professor Satoshi Takahashi, Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, Japan, and the tem are looking into the interaction between binocular stereoscopic clues and monocular stereoscopic clues in binocular single vision. Their goal is to explore the effects on depth judgment and the researchers will use their findings to construct a training system that enables correct depth judgement in binocular single vision. This extensive research will involve conducting inspections on a large number of participants and developing effective methods for inspecting binocular stereoscopic function. This will lead to the development of a device that can easily diagnose the binocular stereoscopic function of the participants and enable early detection. Takahashi and the team will also explore training methods that can help individuals recover lost eye function and encourage behavioural changes that will reduce incidence of eye problems.
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Lü, Chao Hui, Jia Ying Pan, Chen Zhang, and Hui Ren. "Design and Implementation of a Stereoscopic Video Player for a Time-Division Display." Applied Mechanics and Materials 577 (July 2014): 1008–11. http://dx.doi.org/10.4028/www.scientific.net/amm.577.1008.
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Three-dimensional video technology is becoming more and more popular, because it can provide a better natural depth perception. In this paper, a stereoscopic video player for a time-division display is designed and implemented, and people can use 3D Shutter Glasses to watch stereoscopic video by the player. It mainly focuses on the process of designing a Direct3D application, and the special handling of NVIDIA 3D Vision system for stereoscopic video. Upon examination, the stereoscopic video player can provide stereoscopic perception and good immersive experience.
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Wade, Nicholas J. "On the Art of Binocular Rivalry." i-Perception 12, no. 6 (November 2021): 204166952110538. http://dx.doi.org/10.1177/20416695211053877.
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Binocular rivalry has a longer descriptive history than stereoscopic depth perception both of which were transformed by Wheatstone's invention of the stereoscope. Thereafter, artistic interest in binocular vision has been largely confined to stereopsis. A brief survey of research on binocular contour rivalry is followed by anaglyphic examples of its expression as art. Rivalling patterns can be photographs, graphics, and combinations of them. In addition, illustrations of binocular lustre and interactions between rivalry and stereopsis are presented, as are rivalling portraits of some pioneers of the science and art of binocular vision. The question of why a dynamic process like binocular rivalry has been neglected in visual art is addressed.
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Parker, Andrew J., Jackson E. T. Smith, and Kristine Krug. "Neural architectures for stereo vision." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1697 (June 19, 2016): 20150261. http://dx.doi.org/10.1098/rstb.2015.0261.
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Stereoscopic vision delivers a sense of depth based on binocular information but additionally acts as a mechanism for achieving correspondence between patterns arriving at the left and right eyes. We analyse quantitatively the cortical architecture for stereoscopic vision in two areas of macaque visual cortex. For primary visual cortex V1, the result is consistent with a module that is isotropic in cortical space with a diameter of at least 3 mm in surface extent. This implies that the module for stereo is larger than the repeat distance between ocular dominance columns in V1. By contrast, in the extrastriate cortical area V5/MT, which has a specialized architecture for stereo depth, the module for representation of stereo is about 1 mm in surface extent, so the representation of stereo in V5/MT is more compressed than V1 in terms of neural wiring of the neocortex. The surface extent estimated for stereo in V5/MT is consistent with measurements of its specialized domains for binocular disparity. Within V1, we suggest that long-range horizontal, anatomical connections form functional modules that serve both binocular and monocular pattern recognition: this common function may explain the distortion and disruption of monocular pattern vision observed in amblyopia. This article is part of the themed issue ‘Vision in our three-dimensional world’.
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Lankheet, M. J. M., and M. Palmen. "Stereoscopic Transparency and Segregation in Depth." Perception 25, no. 1_suppl (August 1996): 90. http://dx.doi.org/10.1068/v96p0219.
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We previously described the spatiotemporal requirements for binocular correlation in stereopsis using sinusoidal gratings-in-depth (Lankheet and Lennie, 1996 Vision Research36 527 – 538). The use of smooth sinusoidal surfaces emphasised the effects of spatial and temporal integration. Binocular correlation, however, depends not only on integration, but also on segregation at depth discontinuities. In the present experiments we therefore investigated segregation-in-depth, using random dot stereograms that depicted two transparent frontoparallel planes positioned symmetrically on either side of a binocular fixation point. Sensitivity for segregating the two planes was established by adding Gaussian distributed disparity noise to the disparities specifying the planes, and finding the noise amplitude that rendered transparency just detectable. The stimuli consisted of dynamic random-dot displays (dot lifetime 4 frames, at a frame rate of 67 Hz), generated in real time by a Macintosh computer, displayed on a television monitor, and viewed through a stereoscope. We used a method of constant stimuli and a 2AFC procedure. Two transparent planes were presented in one interval, and a single plane, with Gaussian distributed disparity values spanning the same range, was presented in the other. Segregation of stationary patterns was optimal for disparity differences of about ±9 min arc. Differences smaller than ±3 min arc and larger than about ±18 min arc could not be resolved. Motion contrast between the two patterns greatly facilitated segregation in depth. The facilitating effect increased with the difference in motion directions. The optimal speed varied with the difference in disparity.
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Westheimer, Gerald. "Three-dimensional displays and stereo vision." Proceedings of the Royal Society B: Biological Sciences 278, no. 1716 (April 13, 2011): 2241–48. http://dx.doi.org/10.1098/rspb.2010.2777.
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Procedures for three-dimensional image reconstruction that are based on the optical and neural apparatus of human stereoscopic vision have to be designed to work in conjunction with it. The principal methods of implementing stereo displays are described. Properties of the human visual system are outlined as they relate to depth discrimination capabilities and achieving optimal performance in stereo tasks. The concept of depth rendition is introduced to define the change in the parameters of three-dimensional configurations for cases in which the physical disposition of the stereo camera with respect to the viewed object differs from that of the observer's eyes.
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Mitchison, Graeme. "The Neural Representation of Stereoscopic Depth Contrast." Perception 22, no. 12 (December 1993): 1415–26. http://dx.doi.org/10.1068/p221415.
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Stereoscopic vision provides examples of contrast phenomena broadly analogous to those seen with brightness. Several authors have suggested that lateral inhibition between disparity-tuned neurons might underlie these phenomena. This type of lateral inhibition would differ from the more familiar kind which occurs with retinal ganglion cells, where an inhibitory surround has essentially a linear subtractive effect. Lateral inhibition by disparity-tuned units would introduce the nonlinearity of the tuning curve. I argue here that the evidence nonetheless suggests that a linear subtractive mechanism operates in the stereo realm—in fact, that there is a stereo equivalent of the classical centre-surround. This seems at first sight implausible, partly because of the occurrence of the nonlinearity mentioned above, but also because disparity is only provided at certain locations in the retinal field, namely those where appropriate features are matched. I show that both objections can be easily overcome, the first because Laplacian-like centre–surrounds can be constructed from disparity-tuned cells, the second because interpolation can fill in between features, and can provide precisely the quantitative dependence upon disparities of neighbouring features which matches the experimental data.
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Yano, Sumio, and Tetsuo Mitsuhashi. "Perception of depth movement and temporal frequency characteristics of stereoscopic vision." Electronics and Communications in Japan (Part III: Fundamental Electronic Science) 76, no. 9 (1993): 99–111. http://dx.doi.org/10.1002/ecjc.4430760910.
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Gillam, B., and H. A. Sedgwick. "The Interaction of Stereopsis and Perspective in the Perception of Depth." Perception 25, no. 1_suppl (August 1996): 59. http://dx.doi.org/10.1068/v96p0216.
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When only stereoscopic information is available, the slant of a single isolated surface around a vertical axis is often greatly underestimated. If two small objects (probes), separated horizontally by several degrees, are displayed in front of such a surface, the depth of the probes is perceived relative to the perceived slant of the background surface, leading to systematic misperception of the point of subjective equality (PSE) of the distances of the probes from the observer (Mitchison and Westheimer, 1984 Vision Research24 1063 – 1073; Gillam et al, 1993 Perception22 Supplement, 35). In the present study we found that when we added global perspective information to the background surface, thus increasing its perceived slant, this substantially improved the PSE of the probes. Alternatively, when we added frontal stereoscopic surfaces above and below the background surface, thus providing gradients of disparity discontinuities across the surface boundaries, this also produced an improvement in the perceived slant of the background surface, but produced an even greater improvement in the PSE of the probes. These results imply that the local stereoscopic information specifying the depth of each probe relative to the background surface is integrated with the perceived slant of the background surface, whether specified by global stereoscopic information or by global perspective information, to determine the relative depth of the probes. This integration of local stereoscopic information with global slant information appears to be more complete, however, when the global information is provided by stereopsis rather than by perspective.
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Gillam, Barbara. "An ecological approach to binocular vision." i-Perception 13, no. 3 (May 2022): 204166952211038. http://dx.doi.org/10.1177/20416695221103895.
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An ecological approach to binocular vision was already demonstrated in Wheatstone's initial stereograms and was explicitly called for by J. J. Gibson, but detailed analysis and experimentation supporting this approach has been more recent. This paper discusses several aspects of this more recent research on environmentally occurring spatial layouts that can influence binocular vision. These include gradients of depth and regions that can be seen by only one eye. The resolution of local stereoscopic ambiguity by more global factors is also discussed.
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Frey, Jérémy, Aurélien Appriou, Fabien Lotte, and Martin Hachet. "Classifying EEG Signals during Stereoscopic Visualization to Estimate Visual Comfort." Computational Intelligence and Neuroscience 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/2758103.
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With stereoscopic displays a sensation of depth that is too strong could impede visual comfort and may result in fatigue or pain. We used Electroencephalography (EEG) to develop a novel brain-computer interface that monitors users’ states in order to reduce visual strain. We present the first system that discriminates comfortable conditions from uncomfortable ones during stereoscopic vision using EEG. In particular, we show that either changes in event-related potentials’ (ERPs) amplitudes or changes in EEG oscillations power following stereoscopic objects presentation can be used to estimate visual comfort. Our system reacts within 1 s to depth variations, achieving 63% accuracy on average (up to 76%) and 74% on average when 7 consecutive variations are measured (up to 93%). Performances are stable (≈62.5%) when a simplified signal processing is used to simulate online analyses or when the number of EEG channels is lessened. This study could lead to adaptive systems that automatically suit stereoscopic displays to users and viewing conditions. For example, it could be possible to match the stereoscopic effect with users’ state by modifying the overlap of left and right images according to the classifier output.
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Wade, Nicholas J. "On the Late Invention of the Stereoscope." Perception 16, no. 6 (December 1987): 785–818. http://dx.doi.org/10.1068/p160785.
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It was not until 1838, when Wheatstone published his account of the stereoscope, that stereoscopic depth perception entered into the body of binocular phenomena. It is argued that the stereoscope was not invented earlier because the phenomenon of stereopsis based on disparity had not been adequately described. This was the case despite the fact that there had been earlier descriptions of tasks that could be performed better with two eyes than with one; the perceptual deficits attendant upon the loss of one eye had been remarked upon; analyses of the projections to each eye were commonplace, and binocular disparities were accurately illustrated; moreover, binocular microscopes and telescopes had been made over a century earlier. Theories of binocular vision were generally confined to accounting for singleness of vision with two eyes, and the concepts employed to account for this were visible direction, corresponding retinal points, and union in the brain. The application of these concepts inhibited any consideration of disparities, other than for yielding diplopia. When perception of the third dimension was addressed by Berkeley at the beginning of the eighteenth century, it was in the context of monocular vision and binocular convergence. Thereafter visual direction became the province for binocular vision and it was analysed in terms of geometrical optics, whereas visual distance was examined in the context of learned associations between vision and touch. This artificial division was challenged initially with respect to visual direction and later with respect to stereopsis. An additional factor delaying the invention of the stereoscope was that experiments on binocular vision generally involved abnormal convergence on extended objects. Wheatstone's accidental observation of stereopsis was under artificial conditions in which disparity alone defined the binocular depth perceived. Once invented the stereoscope was enthusiastically embraced by students of vision. It is suggested that the ease with which retinal disparity could be manipulated in stereopairs has led to an exaggeration of its importance in space perception.
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TARFAOUI, N., Y. NOCHEZ, and PJ PISELLA. "Customized intraocular lenses enhance binocular depth-of-focus and optimize stereoscopic vision." Acta Ophthalmologica 90 (August 6, 2012): 0. http://dx.doi.org/10.1111/j.1755-3768.2012.s135.x.
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Vedamurthy, Indu, David C. Knill, Samuel J. Huang, Amanda Yung, Jian Ding, Oh-Sang Kwon, Daphne Bavelier, and Dennis M. Levi. "Recovering stereo vision by squashing virtual bugs in a virtual reality environment." Philosophical Transactions of the Royal Society B: Biological Sciences 371, no. 1697 (June 19, 2016): 20150264. http://dx.doi.org/10.1098/rstb.2015.0264.
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Stereopsis is the rich impression of three-dimensionality, based on binocular disparity—the differences between the two retinal images of the same world. However, a substantial proportion of the population is stereo-deficient, and relies mostly on monocular cues to judge the relative depth or distance of objects in the environment. Here we trained adults who were stereo blind or stereo-deficient owing to strabismus and/or amblyopia in a natural visuomotor task—a ‘bug squashing’ game—in a virtual reality environment. The subjects' task was to squash a virtual dichoptic bug on a slanted surface, by hitting it with a physical cylinder they held in their hand. The perceived surface slant was determined by monocular texture and stereoscopic cues, with these cues being either consistent or in conflict, allowing us to track the relative weighting of monocular versus stereoscopic cues as training in the task progressed. Following training most participants showed greater reliance on stereoscopic cues, reduced suppression and improved stereoacuity. Importantly, the training-induced changes in relative stereo weights were significant predictors of the improvements in stereoacuity. We conclude that some adults deprived of normal binocular vision and insensitive to the disparity information can, with appropriate experience, recover access to more reliable stereoscopic information. This article is part of the themed issue ‘Vision in our three-dimensional world’.
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So, Richard H. Y., W. S. Wong, Romeo Yip, Andrew K. C. Lam, and Patrick Ting. "Benefits of Matching Accommodative Demands to Vergence Demands in a Binocular Head-Mounted Display: A Study on Stereo Fusion Times." Presence: Teleoperators and Virtual Environments 20, no. 6 (December 1, 2011): 545–58. http://dx.doi.org/10.1162/pres_a_00076.
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Current head-mounted displays (HMDs) provide only a fixed lens focus. Viewers have to decouple their accommodation and vergence responses when viewing stereoscopic images presented on an HMD. This study investigates the time taken to fuse a pair of stereoscopic images displayed on an HMD when the accommodative demand is matched to the vergence demand. Four testing conditions exhausting the factorial combinations of accommodative demands (2.5 D and 0.5 D) and vergence demands (2.5 MA and 0.5 MA) were investigated. The results indicate that viewers take a significantly shorter amount of time to fuse a pair of stereoscopic images (i.e., fusion time) when the accommodative demand and the stereoscopic depth cues match. Further analysis suggests that an unnatural demand for the eyes to verge toward stereoscopic images whose stereo depth is farther than the accommodative demand is associated with significantly longer fusion time. This study evaluates the potential benefits of using a dynamically adjustable lens focus in future designs of HMDs.
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Alazi. "Stereoscopy, Brown Syndrome, and Duane Syndrome: A Literature Review." Sriwijaya Journal of Ophthalmology 6, no. 1 (June 28, 2022): 179–85. http://dx.doi.org/10.37275/sjo.v6i1.79.
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Stereoscopic is the ability to perceive visual objects in the depth dimension (in the third dimension). Having a stereoscopic vision is a goal to be achieved. Brown Syndrome is a rare form of strabismus in which an ocular motility disorder is characterized by restriction of the elevation of the adducted eye, whereas Duane Syndrome is a spectrum of eye motility disorders characterized by anomalous contractions of the medial and lateral rectus muscles in actual or attempted adduction of one or both eyes. Involved. Diagnosis and therapy are performed depending on the underlying condition of the disorder.
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Hodges, Larry F., and Elizabeth Thorpe Davis. "Geometric Considerations for Stereoscopic Virtual Environments." Presence: Teleoperators and Virtual Environments 2, no. 1 (January 1993): 34–43. http://dx.doi.org/10.1162/pres.1993.2.1.34.
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We examine the relationship among the different geometries implicit in a stereoscopic virtual environment. In particular, we examine in detail the relationship of retinal disparity, fixation point, binocular visual direction, and screen parallax. We introduce the concept of a volumetric spatial unit called a stereoscopic voxel. Due to the shape of stereoscopic voxels, apparent depth of points in space may be affected by their horizontal placement.
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Kingdom, Frederick A. A., Lynn R. Ziegler, and Robert F. Hess. "Luminance spatial scale facilitates stereoscopic depth segmentation." Journal of the Optical Society of America A 18, no. 5 (May 1, 2001): 993. http://dx.doi.org/10.1364/josaa.18.000993.
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Wei, Lijun, Cindy Cappelle, Yassine Ruichek, and Frédérick Zann. "GPS and Stereovision-Based Visual Odometry: Application to Urban Scene Mapping and Intelligent Vehicle Localization." International Journal of Vehicular Technology 2011 (May 17, 2011): 1–17. http://dx.doi.org/10.1155/2011/439074.
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We propose an approach for vehicle localization in dense urban environments using a stereoscopic system and a GPS sensor. Stereoscopic system is used to capture the stereo video flow, to recover the environments, and to estimate the vehicle motion based on feature detection, matching, and triangulation from every image pair. A relative depth constraint is applied to eliminate the tracking couples which are inconsistent with the vehicle ego-motion. Then the optimal rotation and translation between the current and the reference frames are computed using an RANSAC based minimization method. Meanwhile, GPS positions are obtained by an on-board GPS receiver and periodically used to adjust the vehicle orientations and positions estimated by stereovision. The proposed method is tested with two real sequences obtained by a GEM vehicle equipped with a stereoscopic system and a RTK-GPS receiver. The results show that the vision/GPS integrated trajectory can fit the ground truth better than the vision-only method, especially for the vehicle orientation. And vice-versa, the stereovision-based motion estimation method can correct the GPS signal failures (e.g., GPS jumps) due to multipath problem or other noises.
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Wilcox, Laurie M., and Philip A. Duke. "Spatial and Temporal Properties of Stereoscopic Surface Interpolation." Perception 34, no. 11 (November 2005): 1325–38. http://dx.doi.org/10.1068/p5437.
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It is well established that under a wide range of conditions when a sparse collection of texture elements varies smoothly in depth, the spaces between the elements are assigned depth values. This disparity interpolation process has been studied in an effort to define some of its fundamental spatial and temporal constraints. To assess disparity interpolation we employed two tasks: a novel task that relies on the bisection of illusory boundaries created when subjective stereoscopic surfaces intersect, and one that relies on a 3-D shape discrimination. The results of both experiments show that there is no improvement in performance when texture density is increased from near 0.20 to 0.85 or when exposure duration is increased from 50–100 to 1000 ms. This lack of dependence on the addition of features that define the interpolated surface, along with the abrupt decline in performance below a critical value, is consistent with the view that surface interpolation is an important function of human stereoscopic vision.
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O’Keefe, Eleanor, Charles Lloyd, Tommy Bullock, Alex Van Atta, and Marc Winterbottom. "Evaluating the effect of stereoscopic display crosstalk on simulated remote vision system depth discrimination." Electronic Imaging 2019, no. 3 (January 13, 2019): 639–1. http://dx.doi.org/10.2352/issn.2470-1173.2019.3.sda-639.
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Li, Hao Jun, and Yue Sheng Zhu. "A New Approach of 2D-to-3D Video Conversion and Its Implementation on Embedded System." Applied Mechanics and Materials 58-60 (June 2011): 2552–57. http://dx.doi.org/10.4028/www.scientific.net/amm.58-60.2552.
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Rather than based on the stereo vision principle and the relationship between the camera position and the video scene objects used in most of current 2D-to-3D video conversion algorithms, a new prediction method of video depth information based on video frame differences is proposed and implemented on an embedded platform in this paper. 3D stereoscopic video sequences are generated by using the original 2D video sequences and the depth information. The theoretical analysis and experimental results have showed that the proposed method is more feasible and efficiency compared with the current algorithms.
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IJsselsteijn, W. A., H. de Ridder, and R. Hamberg. "Relevant Perceptual Factors in Stereoscopic Displays: Image Disparity, Convergence Distance, and Focus Length." Perception 26, no. 1_suppl (August 1997): 185. http://dx.doi.org/10.1068/v970120.
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Traditionally, visually relevant factors in stereoscopic displays have been investigated within a performance-oriented framework, focusing on the veridicality of depth perception. However, for some applications, most notably in the areas of broadcasting and entertainment, an appreciation-oriented approach seems to be more relevant. Within this framework, we investigated the influence of image disparity, convergence distance, and focus length on the subjective assessment of depth, naturalness of depth, and quality of depth (or preference). Twelve observers with normal or corrected-to-normal vision and good stereopsis viewed a fully randomised presentation of stereoscopic still images that varied systematically in image disparity (six levels of camera base difference: 0, 4, 8, 12, 16, and 24 cm), convergence distance (two levels: 1.30 m and 2.60 m) and focus length (two levels: 10 mm and 20 mm). Each observer was asked to rate, in separate counterbalanced sessions, his/her impression of depth, naturalness of depth, and quality of depth. The results indicate that observers prefer a stereoscopic presentation of images over a monoscopic presentation. A clear optimum was found at 4 cm image disparity for subjective judgments of naturalness and of quality. Depth judgements increased up to an image disparity of 12 cm, a result that is in line with earlier psychophysical literature. There was an effect of focus length only at extreme image disparities. An effect of convergence distance was also found that can be adequately explained by rescaling to match the effective visual disparities. Although there was a strong linear correlation between naturalness and quality (r = 0.96), a small but systematic deviation could be observed. This deviation was best modelled by a linear quality model that incorporates both naturalness and depth.
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Lee, Sangwoo, Younghui Kim, Jungjin Lee, Kyehyun Kim, Kyunghan Lee, and Junyong Noh. "Depth manipulation using disparity histogram analysis for stereoscopic 3D." Visual Computer 30, no. 4 (September 4, 2013): 455–65. http://dx.doi.org/10.1007/s00371-013-0868-3.
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Guttmann, Josef, and Hanns-Christof Spatz. "Frequency of Fusion and of Loss of Fusion, and Binocular Depth Perception with Alternating Stimulus Presentation." Perception 14, no. 1 (February 1985): 5–12. http://dx.doi.org/10.1068/p140005.
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Stereoscopic vision was investigated with an experimental design allowing dichoptic stimulus presentation at different frequencies of image alternation. For twenty subjects the frequency of binocular fusion and the frequency of loss of fusion to one stereoscopic image was measured as a function of the convergence angle. In thirteen subjects no dependence of the fusion frequency was found, while seven subjects showed a marked increase of the fusion frequency with increasing angle of convergence. In all cases the frequency of fusion was higher than the frequency of loss of fusion. Both frequencies, however, are lower than the flicker fusion frequency. Under conditions where no monocular cues and no references for stereoptic depth comparisons were presented, the apparent distance of the image from the observer could not be assessed, but perception of relative motion in depth was possible. All subjects assessed the direction of motion accurately down to changes of the convergence angle of 0.2 deg s−1.
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van Ee, Raymond. "Correlation between Stereoanomaly and Perceived Depth When Disparity and Motion Interact in Binocular Matching." Perception 32, no. 1 (January 2003): 67–84. http://dx.doi.org/10.1068/p3459.
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The aim of this study was to find out to what extent binocular matching is facilitated by motion when stereoanomalous and normal subjects estimate the perceived depth of a 3-D stimulus containing excessive matching candidates. Thirty subjects viewed stimuli that consisted of bars uniformly distributed inside a volume. They judged the perceived depth-to-width ratio of the volume by adjusting the aspect ratio of an outline rectangle (a metrical 3-D task). Although there were large inter-subject differences in the depth perceived, the experimental results yielded a good correlation with stereoanomaly (the inability to distinguish disparities of different magnitudes and/or signs in part of the disparity spectrum). The results cannot be explained solely by depth-cue combination. Since up to 30% of the population is stereo-anomalous, stereoscopic experiments would yield more informative results if subjects were first characterized with regard to their stereo capacities. Intriguingly, it was found that motion does not help to define disparities in subjects who are able to perceive depth-from-disparity in half of the disparity spectrum. These stereoanomalous subjects were found to rely completely on the motion signals. This suggests that the perception of volumetric depth in subjects with normal stereoscopic vision requires the joint processing of crossed and uncrossed disparities.
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Kaufman, James, Teresa King, Sunhee Bai, Lloyd Kaufman, Stefan Edlund, and Richard Noble. "Perceptual distance and the constancy of size and stereoscopic depth." Spatial Vision 19, no. 5 (2006): 439–57. http://dx.doi.org/10.1163/156856806778457377.
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Adams, Wendy J., Erich W. Graf, and Matt Anderson. "Disruptive coloration and binocular disparity: breaking camouflage." Proceedings of the Royal Society B: Biological Sciences 286, no. 1896 (February 13, 2019): 20182045. http://dx.doi.org/10.1098/rspb.2018.2045.
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Many species employ camouflage to disguise their true shape and avoid detection or recognition. Disruptive coloration is a form of camouflage in which high-contrast patterns obscure internal features or break up an animal's outline. In particular, edge enhancement creates illusory, or ‘fake’ depth edges within the animal's body. Disruptive coloration often co-occurs with background matching, and together, these strategies make it difficult for an observer to visually segment an animal from its background. However, stereoscopic vision could provide a critical advantage in the arms race between perception and camouflage: the depth information provided by binocular disparities reveals the true three-dimensional layout of a scene, and might, therefore, help an observer to overcome the effects of disruptive coloration. Human observers located snake targets embedded in leafy backgrounds. We analysed performance (response time) as a function of edge enhancement, illumination conditions and the availability of binocular depth cues. We confirm that edge enhancement contributes to effective camouflage: observers were slower to find snakes whose patterning contains ‘fake’ depth edges. Importantly, however, this effect disappeared when binocular depth cues were available. Illumination also affected detection: under directional illumination, where both the leaves and snake produced strong cast shadows, snake targets were localized more quickly than in scenes rendered under ambient illumination. In summary, we show that illusory depth edges, created via disruptive coloration, help to conceal targets from human observers. However, cast shadows and binocular depth information improve detection by providing information about the true three-dimensional structure of a scene. Importantly, the strong interaction between disparity and edge enhancement suggests that stereoscopic vision has a critical role in breaking camouflage, enabling the observer to overcome the disruptive effects of edge enhancement.
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Mitchison, Graeme. "Planarity and Segmentation in Stereoscopic Matching." Perception 17, no. 6 (December 1988): 753–82. http://dx.doi.org/10.1068/p170753.
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The matching of stereograms which contain periodic patterns suggests ways in which the stereo correspondence problem may be solved in human vision. The stereograms seem to be segmented by coarse-scale features. Within each segment a set of matches approximating a plane is chosen. In regions with periodic patterns there may be many such planar sets, and the disparity of coarse-scale features seems to guide the choice of a particular set. This emphasis on planarity may reflect the occurrence of correlation-like operations in cortical neurons. An attractive possibility is that segmentation effectively delimits areas of the visual field within which disparities are likely to be slow changing (eg local tangent planes to surfaces) so that the correlation sums evaluated in a segment can give the best estimate of depth. A mechanism of this kind cannot account for all of stereo matching, since not all visual objects are well described by ensembles of planes. But it is likely to be a component of the matching system which is particularly important where images are ‘noisy’ and averaging is needed to extract reliable disparities.
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Fazlyyyakhmatov, Marsel, Nataly Zwezdochkina, and Vladimir Antipov. "The EEG Activity during Binocular Depth Perception of 2D Images." Computational Intelligence and Neuroscience 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/5623165.
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The central brain functions underlying a stereoscopic vision were a subject of numerous studies investigating the cortical activity during binocular perception of depth. However, the stereo vision is less explored as a function promoting the cognitive processes of the brain. In this work, we investigated a cortical activity during the cognitive task consisting of binocular viewing of a false image which is observed when the eyes are refocused out of the random-dot stereogram plane (3D phenomenon). The power of cortical activity before and after the onset of the false image perception was assessed using the scull EEG recording. We found that during stereo perception of the false image the power of alpha-band activity decreased in the left parietal area and bilaterally in frontal areas of the cortex, while activity in beta-1, beta-2, and delta frequency bands remained to be unchanged. We assume that this suppression of alpha rhythm is presumably associated with increased attention necessary for refocusing the eyes at the plane of the false image.
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Gupta, Reena, Richa Jangra, Gaurav Dubey, Ramesh Hooda, and Nirmal Parmar. "Efficacy of vision therapy in impaired stereoscopic depth with intermittent exotropia (true divergence excess) with unilateral amblyopia: a case report." International Journal Of Community Medicine And Public Health 7, no. 2 (January 28, 2020): 773. http://dx.doi.org/10.18203/2394-6040.ijcmph20200466.
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Divergence excess (DE) can be described clinically as exotropia at far greater than the near deviation by at least 10 prism dioptres (PD). We are reporting a rare case of 25-year-old female visited in the eye department for a routine eye check-up with a history of decreased vision in one eye. On examination, it was detected as a case of unilateral amblyopia with intermittent exotropia of true divergence excess with high accommodative-convergence over accommodation (AC/A) ratio. The patient was asymptomatic from exo-deviation due to the presence of binocular vision and good fusional reserve. The patient was started on active conventional vision therapy along with occlusion therapy. Post 16 weeks of constant therapy, a vision assessment with complete squint assessment along with binocular vision tests were performed. The result interprets to support the use of active conventional vision therapy as an integral part of the clinical treatment of amblyopia and intermittent exotropia. The rate of recovery of several monocular functions monitored during the vision therapy period provides the evidence of neural plasticity at multiple sites in the visual pathway in this adult amblyope. Therefore, if an ordered plan is being followed for the management of the patient of unilateral amblyopia and divergence excess, it can yield long-lasting improvement in visual acuity and binocular functions of any age.
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IJsselsteijn, W. A., J. Freeman, S. E. Avons, J. Davidoff, H. de Ridder, and R. Hamberg. "Continuous Assessment of Presence in Stereoscopic Displays." Perception 26, no. 1_suppl (August 1997): 186. http://dx.doi.org/10.1068/v970359.
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Presence, a sense of ‘being there’ evoked by a display, can be regarded as a concept of central importance in the evaluation of broadcasting and entertainment services in general and virtual reality applications in particular. Subjective methods of assessing presence that have either been used or proposed to date do not provide a measure of temporal variation in observers' presence. To overcome this limitation, we have applied the method of continuous assessment (ITU-R, BT 500-7) to the measurement of presence. Thirty observers (twelve at IPO, eighteen at UoE) with normal or corrected-to-normal vision and good stereo-acuity viewed a stereoscopic film. While watching, observers were asked to continuously rate their perceptions of depth, naturalness and presence. The stimulus material varied considerably in the amount and strength of the visual cues presented over time. This enabled us to investigate whether the extent of sensory information presented to an observer was a determinant of presence, as proposed by Sheridan [1992 Presence: Teleoperators and Virtual Environments1(1) 120 – 125]. The results, which were very similar across two independent laboratories, suggested that continuous assessment provides a promising methodology for the subjective assessment of temporal variation in the observer's sense of presence. Further, increasing the extent of sensory information presented to an observer may enhance the sense of presence, provided the depth cues introduced are consistent and within natural bounds. [ Note: First and second author in arbitrary order.]
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Beadle, James, C. James Taylor, Kirsti Ashworth, and David Cheneler. "Plant Leaf Position Estimation with Computer Vision." Sensors 20, no. 20 (October 20, 2020): 5933. http://dx.doi.org/10.3390/s20205933.
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Autonomous analysis of plants, such as for phenotyping and health monitoring etc., often requires the reliable identification and localization of single leaves, a task complicated by their complex and variable shape. Robotic sensor platforms commonly use depth sensors that rely on either infrared light or ultrasound, in addition to imaging. However, infrared methods have the disadvantage of being affected by the presence of ambient light, and ultrasound methods generally have too wide a field of view, making them ineffective for measuring complex and intricate structures. Alternatives may include stereoscopic or structured light scanners, but these can be costly and overly complex to implement. This article presents a fully computer-vision based solution capable of estimating the three-dimensional location of all leaves of a subject plant with the use of a single digital camera autonomously positioned by a three-axis linear robot. A custom trained neural network was used to classify leaves captured in multiple images taken of a subject plant. Parallax calculations were applied to predict leaf depth, and from this, the three-dimensional position. This article demonstrates proof of concept of the method, and initial tests with positioned leaves suggest an expected error of 20 mm. Future modifications are identified to further improve accuracy and utility across different plant canopies.
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Häkkinen, J., M. Liinasuo, I. Kojo, and G. Nyman. "Is Stereoscopic Capture Possible with Three-Dimensionally Slanted or Curved Illusory Surfaces?" Perception 25, no. 1_suppl (August 1996): 73. http://dx.doi.org/10.1068/v96l0907.
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The depth of disparate illusory contours affects the perception of background patterns that are enclosed by these contours. If the pattern is repetitive, the depth of the illusory surface is attributed to texture elements even though the texture is in zero disparity. Previous results have suggested that this phenomenon, called stereoscopic capture, is possible only with frontoparallel surfaces (Ramachandran, 1986 Perception & Psychophysics39 361 – 373). We hypothesised that the disruption of stereo capture with three-dimensionally slanted or curved surfaces has been due to the impossibility of consistent rematching of background texture elements. If the texture is designed in such a way that adjacent elements can be rematched to form a surface that is consistent with the three-dimensional structure of the illusory surface, the capture should be possible with complex surfaces. We investigated our hypothesis by showing three-dimensionally slanted and curved surfaces to subjects and changing the pattern of the background texture. According to our results a texture of a constant period can be captured only by a frontoparallel surface; however, if the texture is designed to be consistent with the three-dimensional structure of the complex surface, the texture elements that initially form a frontoparallel surface form a complex surface when they are captured. We conclude that (a) stereoscopic capture is possible with complex three-dimensional surfaces; (b) the possible discrete matches within the background texture determine the possible three-dimensional forms that can be captured and therefore stereoscopic capture should not be characterised only as depth interpolation (Mitchison and McKee, 1987 Vision Research27 285 – 294) between large image elements.
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Guo, Mei, Kang Yue, Haochen Hu, Kai Lu, Yu Han, Shanshan Chen, and Yue Liu. "Neural Research on Depth Perception and Stereoscopic Visual Fatigue in Virtual Reality." Brain Sciences 12, no. 9 (September 11, 2022): 1231. http://dx.doi.org/10.3390/brainsci12091231.
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Virtual reality (VR) technology provides highly immersive depth perception experiences; nevertheless, stereoscopic visual fatigue (SVF) has become an important factor currently hindering the development of VR applications. However, there is scant research on the underlying neural mechanism of SVF, especially those induced by VR displays, which need further research. In this paper, a Go/NoGo paradigm based on disparity variations is proposed to induce SVF associated with depth perception, and the underlying neural mechanism of SVF in a VR environment was investigated. The effects of disparity variations as well as SVF on the temporal characteristics of visual evoked potentials (VEPs) were explored. Point-by-point permutation statistical with repeated measures ANOVA results revealed that the amplitudes and latencies of the posterior VEP component P2 were modulated by disparities, and posterior P2 amplitudes were modulated differently by SVF in different depth perception situations. Cortical source localization analysis was performed to explore the original cortex areas related to certain fatigue levels and disparities, and the results showed that posterior P2 generated from the precuneus could represent depth perception in binocular vision, and therefore could be performed to distinguish SVF induced by disparity variations. Our findings could help to extend an understanding of the neural mechanisms underlying depth perception and SVF as well as providing beneficial information for improving the visual experience in VR applications.
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Méxas, José Geraldo Franco, Karla Bastos Guedes, and Ronaldo da Silva Tavares. "Stereo orthogonal axonometric perspective for the teaching of Descriptive Geometry." Interactive Technology and Smart Education 12, no. 3 (September 21, 2015): 222–40. http://dx.doi.org/10.1108/itse-09-2014-0027.
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Purpose – The purpose of this paper is to present the development of a software for stereo visualization of geometric solids, applied to the teaching/learning of Descriptive Geometry. Design/methodology/approach – The paper presents the traditional method commonly used in computer graphic stereoscopic vision (implemented in C language) and the proposed method (implemented in GeoGebra software). The proposed method is a new methodology for stereo spatial visualization. It uses the orthogonal axonometric perspective obtained from the mongean projections of the object, both concepts studied in Descriptive Geometry course. Findings – The use of stereoscopic techniques has great potential for the improvement of spatial visualization ability, because they allow the understanding of spatial situations presented in complex exercises. The students who tested the proposed method said that it offered a superior stereo vision depth in relation to the traditional matrix method. Research limitations/implications – For future work, the paper suggests to carry out a statistical study to evaluate the educational benefit of the tool, and to investigate the proposed method using the conical axonometric perspective. Practical implications – Create a virtual environment to support the process of teaching/learning Descriptive Geometry and contribute to the development of students ' spatial visualization skills. The software will be available on the Internet, in the GeoGebra libraries. The objective is to increase e-learning, where a greater number of students will study. Social implications – The current goal in Brazil universities is to greatly increase the number of poor students entering as a social inclusion strategy. University courses need more efficient teaching techniques to attend the students, so the e-learning techniques are recommended. Originality/value – This paper’s innovative characteristic comes from the implementation of stereoscopic vision from traditional methods used in Descriptive Geometry, so the proposed method improves both the visualization ability and the Descriptive Geometry basic concepts, which points out to its educational role.
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Neri, Peter, Holly Bridge, and David J. Heeger. "Stereoscopic Processing of Absolute and Relative Disparity in Human Visual Cortex." Journal of Neurophysiology 92, no. 3 (September 2004): 1880–91. http://dx.doi.org/10.1152/jn.01042.2003.
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Stereoscopic vision relies mainly on relative depth differences between objects rather than on their absolute distance in depth from where the eyes fixate. However, relative disparities are computed from absolute disparities, and it is not known where these two stages are represented in the human brain. Using functional MRI (fMRI), we assessed absolute and relative disparity selectivity with stereoscopic stimuli consisting of pairs of transparent planes in depth in which the absolute and relative disparity signals could be independently manipulated (at a local spatial scale). In experiment 1, relative disparity was kept constant, while absolute disparity was varied in one-half the blocks of trials (“mixed” blocks) and kept constant in the remaining one-half (“same” blocks), alternating between blocks. Because neuronal responses undergo adaptation and reduce their firing rate following repeated presentation of an effective stimulus, the fMRI signal reflecting activity of units selective for absolute disparity is expected to be smaller during “same” blocks as compared with “mixed” ones. Experiment 2 similarly manipulated relative disparity rather than absolute disparity. The results from both experiments were consistent with adaptation with differential effects across visual areas such that 1) dorsal areas (V3A, MT+/V5, V7) showed more adaptation to absolute than to relative disparity; 2) ventral areas (hV4, V8/V4α) showed an equal adaptation to both; and 3) early visual areas (V1, V2, V3) showed a small effect in both experiments. These results indicate that processing in dorsal areas may rely mostly on information about absolute disparities, while ventral areas split neural resources between the two types of stereoscopic information so as to maintain an important representation of relative disparity.
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Umeda, Kazumasa, Seiji Tanabe, and Ichiro Fujita. "Representation of Stereoscopic Depth Based on Relative Disparity in Macaque Area V4." Journal of Neurophysiology 98, no. 1 (July 2007): 241–52. http://dx.doi.org/10.1152/jn.01336.2006.
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Stereoscopic vision is characterized by greater visual acuity when a background feature serves as a reference. When a reference is present, the perceived depth of an object is predominantly dependent on this reference. Neural representations of stereoscopic depth are expected to have a relative frame of reference. The conversion of absolute disparity encoded in area V1 to relative disparity begins in area V2, although the information encoded in this area appears to be insufficient for stereopsis. This study examines whether relative disparity is encoded in a higher cortical area. We recorded the responses of V4 neurons from macaque monkeys to various combinations of the absolute disparities of two features: the center patch and surrounding annulus of a dynamic random-dot stereogram. We analyzed the effects of the disparity of the surrounding annulus on the tuning for the disparity of the center patch; the tuning curves of relative-disparity–selective neurons for disparities of the center patch should shift with changes in the disparity of the surrounding annulus. Most V4 tuning curves exhibited significant shifts. The magnitudes of the shifts were larger than those reported for V2 neurons and smaller than that expected for an ideal relative-disparity–selective cell. No correlation was found between the shift magnitude and the degree of size suppression, suggesting that the two phenomena are not the result of a common mechanism. Our results suggest that the coding of relative disparity advances as information flows along the cortical pathway that includes areas V2 and V4.
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Hegarty, M. R., P. B. Hibbard, M. F. Bradshaw, B. De Bruyn, and A. D. Parton. "Anisotropic Temporal Integration in the Perception of Stereoscopic Corrugations." Perception 26, no. 1_suppl (August 1997): 170. http://dx.doi.org/10.1068/v970178.
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Disparity sensitivity for horizontal depth corrugations increases with exposure duration for presentations of up to 1 s (Tyler, 1990 Vision Research30 1877 – 1895). To extend the work of Parton et al (1996 Perception25 67) we investigated whether differences existed in the effects of exposure for corrugations at different orientations. Disparity thresholds were measured for horizontal, vertical, and diagonal gratings with spatial frequencies ranging between 0.1 cycle deg−1 and 0.8 cycle deg−1, as a function of stimulus duration. Stimuli were presented for exposures of between 50 ms and 32 s, and were followed by a random disparity mask, which served the important function of disrupting further processing of stimulus disparity. Thresholds were greatest for vertical gratings. This effect was particularly pronounced for the lowest frequencies. In all conditions, disparity sensitivity improved as exposure duration increased, and continued to do so for all durations tested. For vertical and diagonal gratings, log - log plots of threshold against time showed a linear relationship with a slope of −1 up to 1.0 s, after which time improvements in sensitivity reduced. Horizontal gratings showed a similar relationship, but with thresholds ceasing to decrease significantly after 0.5 s. Temporal integration limits differ with surface orientation, and represent another important difference in our ability to detect and encode depth in stereoscopic surfaces.
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Jama, Michal, and Dale Schinstock. "Parallel Tracking and Mapping for Controlling VTOL Airframe." Journal of Control Science and Engineering 2011 (2011): 1–10. http://dx.doi.org/10.1155/2011/413074.
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This work presents a vision based system for navigation on a vertical takeoff and landing unmanned aerial vehicle (UAV). This is a monocular vision based, simultaneous localization and mapping (SLAM) system, which measures the position and orientation of the camera and builds a map of the environment using a video stream from a single camera. This is different from past SLAM solutions on UAV which use sensors that measure depth, like LIDAR, stereoscopic cameras or depth cameras. Solution presented in this paper extends and significantly modifies a recent open-source algorithm that solves SLAM problem using approach fundamentally different from a traditional approach. Proposed modifications provide the position measurements necessary for the navigation solution on a UAV. The main contributions of this work include: (1) extension of the map building algorithm to enable it to be used realistically while controlling a UAV and simultaneously building the map; (2) improved performance of the SLAM algorithm for lower camera frame rates; and (3) the first known demonstration of a monocular SLAM algorithm successfully controlling a UAV while simultaneously building the map. This work demonstrates that a fully autonomous UAV that uses monocular vision for navigation is feasible.
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Liu, Wei, Liyan Ma, and Mingyue Cui. "Learning-Based Stereoscopic View Synthesis with Cascaded Deep Neural Networks." Journal of Advanced Computational Intelligence and Intelligent Informatics 26, no. 3 (May 20, 2022): 393–406. http://dx.doi.org/10.20965/jaciii.2022.p0393.
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Depth image-based rendering (DIBR) is an important technique in the 2D to 3D conversion process, which renders virtual views with a texture image and the associated depth map. However, certain problems, such as disocclusion, still exist in current DIBR systems. In this study, a new learning-based framework that models conventional DIBR synthesis pipelines is proposed to solve these problems. The proposed model adopts a coarse-to-fine approach to realize virtual view prediction and disocclusion region refinement sequentially in a unified deep learning framework that includes two cascaded joint filter block-based convolutional neural networks (CNNs) and one residual learning-based generative adversarial network (GAN). An edge-guided global looping optimization strategy is adopted to progressively reconstruct the scene structures on the novel view, and a novel directional discounted reconstruction loss is proposed for better training. In this way, our framework performs well in terms of virtual view quality and is more suitable for 2D to 3D conversion applications. The experimental results demonstrate that the proposed method can generate visually satisfactory results.
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Chen, Hung-Jen, Chiuhsiang Joe Lin, Po-Hung Lin, and Zong-Han Guo. "The Effects of 3D and 2D Imaging on Brain Wave Activity in Laparoscopic Training." Applied Sciences 11, no. 2 (January 18, 2021): 862. http://dx.doi.org/10.3390/app11020862.
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The current study tested the effects of a state-of-the-art stereoscopic three-dimensional (3D) display and a traditional two-dimensional (2D) display on performance and mental workload during simulated laparoscopic tasks with different levels of depth perception over a longer duration than in previous publications. Two different simulated laparoscopic tasks with depth perception, peg transfer, and circle-tracing were performed by 12 participants using 2D and 3D vision systems. The task performances (mean completion time and mean error frequency) and mental workload measures (gamma and alpha brain wave activity, blink frequency and NASA-TLX ratings) were recorded as dependent variables. The physiological mental workload measures were collected via a MUSE EEG headband. The 3D vision system had advantages in mean movement time and mean error frequency in the depth-perception peg transfer task. The mean completion time of the non-depth perception circle-tracing task was significantly lower for 2D than for 3D. For the peg transfer task, EEG alpha wave activity was significantly higher for 3D than for 2D. The EEG gamma wave activity for 2D was significantly higher than that for 3D in both tasks. A significantly higher blink frequency was found for both the peg transfer task and the 3D system. The overall NASA-TLX score of the 2D system was significantly higher. The findings of this research suggest that a 3D vision system could decrease stress, state of attentiveness, and mental workload compared with those of a 2D system, and it might reduce the completion time and increase the precision of depth-perception laparoscopic operations.