WorldWideScience

Sample records for binoculars

  1. Binocular astronomy

    CERN Document Server

    Tonkin, Stephen

    2014-01-01

    Binoculars have, for many, long been regarded as an “entry level” observational tool, and relatively few have used them as a serious observing instrument. This is changing! Many people appreciate the relative comfort of two-eyed observing, but those who use binoculars come to realize that they offer more than comfort. The view of the stars is more aesthetically pleasing and therefore binocular observers tend to observe more frequently and for longer periods. Binocular Astronomy, 2nd Edition, extends its coverage of small and medium binoculars to large and giant (i.e., up to 300mm aperture) binoculars and also binoviewers, which brings the work into the realm of serious observing instruments. Additionally, it goes far deeper into the varying optical characteristics of binoculars, giving newcomers and advanced astronomers the information needed to make informed choices on purchasing a pair. It also covers relevant aspects of the physiology of binocular (as in “both eyes”) observation. The first edition ...

  2. What is binocular disparity?

    OpenAIRE

    Lappin, Joseph S.

    2014-01-01

    What are the geometric primitives of binocular disparity? The Venetian blind effect and other converging lines of evidence indicate that stereoscopic depth perception derives from disparities of higher-order structure in images of surfaces. Image structure entails spatial variations of intensity, texture, and motion, jointly structured by observed surfaces. The spatial structure of binocular disparity corresponds to the spatial structure of surfaces. Independent spatial coordinates are not ne...

  3. What is Binocular Disparity?

    OpenAIRE

    Lappin, Joseph S.

    2014-01-01

    What are the geometric primitives of binocular disparity? The Venetian blind effect and other converging lines of evidence indicate that stereo-scopic depth perception derives from disparities of higher-order structure in images of surfaces. Image structure entails spatial variations of in-tensity, texture, and motion, jointly structured by observed surfaces. The spatial structure of bin-ocular disparity corresponds to the spatial struc-ture of surfaces. Independent spatial coordinates are no...

  4. Binocular advantages in reading.

    Science.gov (United States)

    Jainta, Stephanie; Blythe, Hazel I; Liversedge, Simon P

    2014-03-01

    Reading, an essential skill for successful function in today's society, is a complex psychological process involving vision, memory, and language comprehension. Variability in fixation durations during reading reflects the ease of text comprehension, and increased word frequency results in reduced fixation times. Critically, readers not only process the fixated foveal word but also preprocess the parafoveal word to its right, thereby facilitating subsequent foveal processing. Typically, text is presented binocularly, and the oculomotor control system precisely coordinates the two frontally positioned eyes online. Binocular, compared to monocular, visual processing typically leads to superior performance, termed the "binocular advantage"; few studies have investigated the binocular advantage in reading. We used saccade-contingent display change methodology to demonstrate the benefit of binocular relative to monocular text presentation for both parafoveal and foveal lexical processing during reading. Our results demonstrate that denial of a unified visual signal derived from binocular inputs provides a cost to the efficiency of reading, particularly in relation to high-frequency words. Our findings fit neatly with current computational models of eye movement control during reading, wherein successful word identification is a primary determinant of saccade initiation. PMID:24530062

  5. Unmixing binocular signals

    Directory of Open Access Journals (Sweden)

    Sidney R Lehky

    2011-08-01

    Full Text Available Incompatible images presented to the two eyes lead to perceptual oscillations in which one image at a time is visible. Early models portrayed this binocular rivalry as involving reciprocal inhibition between monocular representations of images, occurring at an early visual stage prior to binocular mixing. However, psychophysical experiments found conditions where rivalry could also occur at a higher, more abstract level of representation. In those cases, the rivalry was between image representations dissociated from eye-of-origin information, rather than between monocular representations from the two eyes. Moreover, neurophysiological recordings found the strongest rivalry correlate in inferotemporal cortex, a high-level, predominantly binocular visual area involved in object recognition, rather than early visual structures. An unresolved issue is how can the separate identities of the two images be maintained after binocular mixing in order for rivalry to be possible at higher levels? Here we demonstrate that after the two images are mixed, they can be unmixed at any subsequent stage using a physiologically plausible nonlinear signal-processing algorithm, non-negative matrix factorization, previously proposed for parsing object parts during object recognition. The possibility that unmixed left and right images can be regenerated at late stages within the visual system provides a mechanism for creating various binocular representations and interactions de novo in different cortical areas for different purposes, rather than inheriting then from early areas. This is a clear example how nonlinear algorithms can lead to highly non-intuitive behavior in neural information processing.

  6. Attentional Modulation of Binocular Rivalry

    OpenAIRE

    Chris ePaffen; David eAlais

    2011-01-01

    Ever since Wheatstone initiated the scientific study of binocular rivalry, it has been debated whether the phenomenon is under attentional control. In recent years, the issue of attentional modulation of binocular rivalry has seen a revival. Here we review the classical studies as well as recent advances in the study of attentional modulation of binocular rivalry. We show that (1) voluntary control over binocular rivalry is possible, yet limited, (2) both endogenous and exogenous attention in...

  7. What is Binocular Disparity?

    Directory of Open Access Journals (Sweden)

    Joseph S Lappin

    2014-08-01

    Full Text Available What are the geometric primitives of binocular disparity? The Venetian blind effect and other converging lines of evidence indicate that stereo-scopic depth perception derives from disparities of higher-order structure in images of surfaces. Image structure entails spatial variations of in-tensity, texture, and motion, jointly structured by observed surfaces. The spatial structure of bin-ocular disparity corresponds to the spatial struc-ture of surfaces. Independent spatial coordinates are not necessary for stereoscopic vision. Stere-opsis is highly sensitive to structural disparities associated with local surface shape. Disparate positions on retinal anatomy are neither neces-sary nor sufficient for stereopsis.

  8. What is binocular disparity?

    Science.gov (United States)

    Lappin, Joseph S

    2014-01-01

    What are the geometric primitives of binocular disparity? The Venetian blind effect and other converging lines of evidence indicate that stereoscopic depth perception derives from disparities of higher-order structure in images of surfaces. Image structure entails spatial variations of intensity, texture, and motion, jointly structured by observed surfaces. The spatial structure of binocular disparity corresponds to the spatial structure of surfaces. Independent spatial coordinates are not necessary for stereoscopic vision. Stereopsis is highly sensitive to structural disparities associated with local surface shape. Disparate positions on retinal anatomy are neither necessary nor sufficient for stereopsis. PMID:25161634

  9. Octonions and Binocular Mobilevision

    OpenAIRE

    Juriev, Denis

    1994-01-01

    This paper is devoted to an interaction of 2 objects: the 1st of them is octonions, the classical structure of pure mathematics, the 2nd one is Mobilevision, the recently developped technique of computer graphics. Namely, it is shown that the binocular Mobilevision maybe elaborated by use of the octonionic colour space - the 7-dimensional extension of the classical one, which includes a strange overcolour besides two triples of ordinary ones (blue,green, red for left and right eyes). Contents...

  10. Glossiness representation using binocular color difference.

    Science.gov (United States)

    Jung, Woo-Soon; Moon, Young-Gyu; Park, Jae-Hyun; Song, Jang-Kun

    2013-07-15

    We demonstrate that a binocular color difference can be used to express the surface glossiness of an object on 3D display devices without being accompanied by a specular reflection pattern. A simple image with a binocular color difference provides a similar surface appearance impression to a real object that has the same binocular color difference. It is found that human binocular perception is likely to interpret binocular color difference as spectral reflectance rather than as transparency. Binocular glossiness is caused not only by a binocular lightness difference but also by a chromatic or hue difference. PMID:23939119

  11. Binocular indirect argon laser photocoagulator.

    OpenAIRE

    Mizuno, K

    1981-01-01

    The binocular indirect argon laser photocoagulator was newly designed to enable visualisation of the entire fundus during panretinal laser photocoagulation and to treat retinal tears immediately after buckling procedures of the sclera. The lamp housing of the binocular ophthalmoscope was remodelled and adjusted so that the laser beam and illuminating light are coaxial after leaving the ophthalmoscope. The blocking filter was permanently fixed in the eye-pieces to lighten the weight of the oph...

  12. Binocular Combination of Second-Order Stimuli

    OpenAIRE

    Zhou, Jiawei; Liu, Rong; Zhou, Yifeng; Hess, Robert F.

    2014-01-01

    Phase information is a fundamental aspect of visual stimuli. However, the nature of the binocular combination of stimuli defined by modulations in contrast, so-called second-order stimuli, is presently not clear. To address this issue, we measured binocular combination for first- (luminance modulated) and second-order (contrast modulated) stimuli using a binocular phase combination paradigm in seven normal adults. We found that the binocular perceived phase of second-order gratings depends on...

  13. Binocular rivalry produced by temporal frequency differences

    OpenAIRE

    Alais, David; Parker, Amanda

    2012-01-01

    When the eyes view images that are sufficiently different to prevent binocular fusion, binocular rivalry occurs and the images are seen sequentially in a stochastic alternation. Here we examine whether temporal frequency differences will trigger binocular rivalry by presenting two dynamic random-pixel arrays that are spatially matched but which modulate temporally at two different rates. We found that binocular rivalry between the two temporal frequencies did indeed occur, provided the freque...

  14. Optimization Design for Digital Binoculars

    Institute of Scientific and Technical Information of China (English)

    CEN Jun-bo; CHEN Wei-min; LI Hui; HUANG Shang-lian

    2005-01-01

    In order to develop competitive and high performance/cost ratio of digital binoculars, design scheme should be optimized in term of technical capacity, economic benefit, product performance, risk management, etc. The common optimization method is limited in qualitative analysis, and the parameter optimization method is limited in obtaining optimal parameter only from technical side. Each method has its limitation. Based on the analysis of digital binoculars parameters, optional design schemes are laid down.Analytic hierarchy process combined the qualitative analysis with the quantitative analysis together. The design schemes are optimized, and result is worked out.

  15. Correcting intermittent central suppression improves binocular marksmanship.

    Science.gov (United States)

    Hussey, Eric S

    2007-04-01

    Intermittent central suppression (ICS) is a defect in normal binocular (two-eyed) vision that causes confusion in visual detail. ICS is a repetitive intermittent loss of visual sensation in the central area of vision. As the central vision of either eye "turns on and off", aiming errors in sight can occur that must be corrected when both eyes are seeing again. Any aiming errors in sight might be expected to interfere with marksmanship during two-eyed seeing. We compared monocular (one-eyed, patched) and binocular (two-eyed) marksmanship with pistol shooting with an Army ROTC cadet before and after successful therapy for diagnosed ICS. Pretreatment, monocular marksmanship was significantly better than binocular marksmanship, suggesting defective binocularity reduced accuracy. After treatment for ICS, binocular and monocular marksmanship were essentially the same. Results confirmed predictions that with increased visual stability from correcting the suppression, binocular and monocular marksmanship accuracies should merge. PMID:17484315

  16. Binocular rivalry produced by temporal frequency differences

    OpenAIRE

    David eAlais; Parker, Amanda L.

    2012-01-01

    Binocular rivalry occurs when each eye views images that are markedly different. Rather than seeing a binocular fusion of the two, each image is seen exclusively in a stochastic alternation of the monocular images. Here we examine whether temporal frequency differences will trigger binocular rivalry by presenting two random dot arrays that are spatially matched but which modulate temporally at two different rates and contained no net translation. We found that a perceptual alternation between...

  17. Interactions between binocular rivalry and Gestalt formation

    NARCIS (Netherlands)

    Weert, C.M.; Snoeren, P.R.; Koning, Arno

    2005-01-01

    A question raised a long time ago in binocular rivalry research is whether the phenomenon of binocular rivalry is purely determined by local stimulus properties or that global stimulus properties also play a role. More specifically: do coherent features in a stimulus influence rivalrous behavior? Af

  18. Colour-grapheme synaesthesia affects binocular vision

    Directory of Open Access Journals (Sweden)

    Chris L.E. Paffen

    2011-11-01

    Full Text Available In colour-grapheme synaesthesia, non-coloured graphemes are perceived as being inherently coloured. In recent years, it has become evident that synaesthesia-inducing graphemes can affect visual processing in a manner comparable to real, physical colours. Here, we exploit the phenomenon of binocular rivalry in which incompatible images presented dichoptically compete for conscious expression. Importantly, the competition only arises if the two images are sufficiently different; if the difference between the images is small, the images will fuse into a single mixed percept. We show that achromatic graphemes that induce synaesthetic colour percepts evoke binocular rivalry, while without the synaesthetic percept, they do not. That is, compared to achromatically perceived graphemes, synaesthesia-inducing graphemes increase the predominance of binocular rivalry over binocular fusion. This finding shows that the synaesthetic colour experience can provide the conditions for evoking binocular rivalry, much like stimulus features that induce rivalry in normal vision.

  19. Binocular rivalry from invisible patterns.

    Science.gov (United States)

    Zou, Jinyou; He, Sheng; Zhang, Peng

    2016-07-26

    Binocular rivalry arises when incompatible images are presented to the two eyes. If the two eyes' conflicting features are invisible, leading to identical perceptual interpretations, does rivalry competition still occur? Here we investigated whether binocular rivalry can be induced from conflicting but invisible spatial patterns. A chromatic grating counterphase flickering at 30 Hz appeared uniform, but produced significant tilt aftereffect and orientation-selective adaptation. The invisible pattern also generated significant BOLD activities in the early visual cortex, with minimal response in the parietal and frontal cortical areas. Compared with perceptually matched uniform stimuli, a monocularly presented invisible chromatic grating enhanced the rivalry competition with a low-contrast visible grating presented to the other eye. Furthermore, switching from a uniform field to a perceptually matched invisible chromatic grating produced interocular suppression at approximately 200 ms after onset of the invisible grating. Experiments using briefly presented monocular probes revealed evidence for sustained rivalry competition between two invisible gratings during continuous dichoptic presentations. These findings indicate that even without visible interocular conflict, and with minimal engagement of frontoparietal cortex and consciousness related top-down feedback, perceptually identical patterns with invisible conflict features produce rivalry competition in the early visual cortex. PMID:27354535

  20. Binocular combination of second-order stimuli.

    Science.gov (United States)

    Zhou, Jiawei; Liu, Rong; Zhou, Yifeng; Hess, Robert F

    2014-01-01

    Phase information is a fundamental aspect of visual stimuli. However, the nature of the binocular combination of stimuli defined by modulations in contrast, so-called second-order stimuli, is presently not clear. To address this issue, we measured binocular combination for first- (luminance modulated) and second-order (contrast modulated) stimuli using a binocular phase combination paradigm in seven normal adults. We found that the binocular perceived phase of second-order gratings depends on the interocular signal ratio as has been previously shown for their first order counterparts; the interocular signal ratios when the two eyes were balanced was close to 1 in both first- and second-order phase combinations. However, second-order combination is more linear than previously found for first-order combination. Furthermore, binocular combination of second-order stimuli was similar regardless of whether the carriers in the two eyes were correlated, anti-correlated, or uncorrelated. This suggests that, in normal adults, the binocular phase combination of second-order stimuli occurs after the monocular extracting of the second-order modulations. The sensory balance associated with this second-order combination can be obtained from binocular phase combination measurements. PMID:24404180

  1. Binocular combination of second-order stimuli.

    Directory of Open Access Journals (Sweden)

    Jiawei Zhou

    Full Text Available Phase information is a fundamental aspect of visual stimuli. However, the nature of the binocular combination of stimuli defined by modulations in contrast, so-called second-order stimuli, is presently not clear. To address this issue, we measured binocular combination for first- (luminance modulated and second-order (contrast modulated stimuli using a binocular phase combination paradigm in seven normal adults. We found that the binocular perceived phase of second-order gratings depends on the interocular signal ratio as has been previously shown for their first order counterparts; the interocular signal ratios when the two eyes were balanced was close to 1 in both first- and second-order phase combinations. However, second-order combination is more linear than previously found for first-order combination. Furthermore, binocular combination of second-order stimuli was similar regardless of whether the carriers in the two eyes were correlated, anti-correlated, or uncorrelated. This suggests that, in normal adults, the binocular phase combination of second-order stimuli occurs after the monocular extracting of the second-order modulations. The sensory balance associated with this second-order combination can be obtained from binocular phase combination measurements.

  2. Binocular rivalry produced by temporal frequency differences

    Directory of Open Access Journals (Sweden)

    David eAlais

    2012-07-01

    Full Text Available Binocular rivalry occurs when each eye views images that are markedly different. Rather than seeing a binocular fusion of the two, each image is seen exclusively in a stochastic alternation of the monocular images. Here we examine whether temporal frequency differences will trigger binocular rivalry by presenting two random dot arrays that are spatially matched but which modulate temporally at two different rates and contained no net translation. We found that a perceptual alternation between the two temporal frequencies did indeed occur, provided the frequencies were sufficiently different, indicating that temporal information can produce binocular rivalry in the absence of spatial conflict. This finding is discussed with regard to the dependence of rivalry on conflict between spatial and temporal channels.

  3. Evaluating relative accommodations in general binocular dysfunctions

    OpenAIRE

    García Muñoz, Ángel; Cacho Martínez, Pilar; Lara Lacarcel, Francisco

    2001-01-01

    Purpose. To examine the relationship between relative accommodation and general binocular disorders and to establish their importance in the diagnosis of these anomalies. Methods. We analyzed data of negative relative accommodation (NRA) and positive relative accommodation (PRA) in 69 patients with nonstrabismic binocular anomalies. Results. Statistical analysis showed that low values of NRA and PRA were not associated with any particular disorder. High values of PRA (>3.50 D) were related to...

  4. Insights from Intermittent Binocular Rivalry and EEG

    OpenAIRE

    Pitts, Michael A.; Juliane eBritz

    2011-01-01

    Novel stimulation and analytical approaches employed in EEG studies of ambiguous figures have recently been applied to binocular rivalry. The combination of intermittent stimulus presentation and EEG source imaging has begun to shed new light on the neural underpinnings of binocular rivalry. Here, we review the basics of the intermittent paradigm and highlight methodological issues important for interpreting previous results and designing future experiments. We then outline current analytical...

  5. Hierarchy of cortical responses underlying binocular rivalry

    OpenAIRE

    Lee, Sang-Hun; Blake, Randolph; Heeger, David J.

    2007-01-01

    During binocular rivalry, physical stimulation is dissociated from conscious visual awareness. Human brain imaging reveals a tight linkage between the neural events in human primary visual cortex (V1) and the dynamics of perceptual waves during transitions in dominance during binocular rivalry. Here, we report results from experiments in which observers’ attention was diverted from the rival stimuli, implying that: competition between two rival stimuli involves neural circuits in V1, and atte...

  6. Binocular contrast discrimination needs monocular multiplicative noise

    Science.gov (United States)

    Ding, Jian; Levi, Dennis M.

    2016-01-01

    The effects of signal and noise on contrast discrimination are difficult to separate because of a singularity in the signal-detection-theory model of two-alternative forced-choice contrast discrimination (Katkov, Tsodyks, & Sagi, 2006). In this article, we show that it is possible to eliminate the singularity by combining that model with a binocular combination model to fit monocular, dichoptic, and binocular contrast discrimination. We performed three experiments using identical stimuli to measure the perceived phase, perceived contrast, and contrast discrimination of a cyclopean sine wave. In the absence of a fixation point, we found a binocular advantage in contrast discrimination both at low contrasts (<4%), consistent with previous studies, and at high contrasts (≥34%), which has not been previously reported. However, control experiments showed no binocular advantage at high contrasts in the presence of a fixation point or for observers without accommodation. We evaluated two putative contrast-discrimination mechanisms: a nonlinear contrast transducer and multiplicative noise (MN). A binocular combination model (the DSKL model; Ding, Klein, & Levi, 2013b) was first fitted to both the perceived-phase and the perceived-contrast data sets, then combined with either the nonlinear contrast transducer or the MN mechanism to fit the contrast-discrimination data. We found that the best model combined the DSKL model with early MN. Model simulations showed that, after going through interocular suppression, the uncorrelated noise in the two eyes became anticorrelated, resulting in less binocular noise and therefore a binocular advantage in the discrimination task. Combining a nonlinear contrast transducer or MN with a binocular combination model (DSKL) provides a powerful method for evaluating the two putative contrast-discrimination mechanisms. PMID:26982370

  7. Binocular form deprivation influences the visual cortex

    Institute of Scientific and Technical Information of China (English)

    Mingming Liu; Chuanhuang Weng; Hanping Xie; Wei Qin

    2012-01-01

    1a-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors are considered to play a crucial role in synaptic plasticity in the developing visual cortex. In this study, we established a rat model of binocular form deprivation by suturing the rat binocular eyelids before eye-opening at postnatal day 14. During development, the decay time of excitatory postsynaptic currents mediated by 1a-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid receptors of normal rats became longer after eyeopening; however, the decay time did not change significantly in binocular form deprivation rats. The peak value in the normal group became gradually larger with age, but there was no significant change in the binocular form deprivation group. These findings indicate that binocular form deprivation influences the properties of excitatory postsynaptic currents mediated by β-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid receptors in the rat visual cortex around the end of the critical period, indicating that form stimulation is associated with the experience-dependent modification of neuronal synapses in the visual cortex.

  8. Insights from intermittent binocular rivalry and EEG

    Directory of Open Access Journals (Sweden)

    Michael A Pitts

    2011-09-01

    Full Text Available Novel stimulation and analytical approaches employed in EEG studies of ambiguous figures have recently been applied to binocular rivalry. The combination of intermittent stimulus presentation and EEG source imaging has begun to shed new light on the neural underpinnings of binocular rivalry. Here, we review the basics of the intermittent paradigm and highlight methodological issues important for interpreting previous results and designing future experiments. We then outline current analytical approaches, including EEG microstates, event-related potentials, and statistically-based source estimation, and propose a spatio-temporal model that integrates findings from several studies. Finally, we discuss the advantages and limitations of using binocular rivalry as a tool to investigate the neural basis of perceptual awareness.

  9. Binocular summation of contrast remains intact in strabismic amblyopia

    OpenAIRE

    Baker, Daniel H.; Meese, Tim S.; Mansouri, Behzad; Hess, Robert F.

    2007-01-01

    PURPOSE. Strabismic amblyopia is typically associated with several visual deficits, including loss of contrast sensitivity in the amblyopic eye and abnormal binocular vision. Binocular summation ratios (BSRs) are usually assessed by comparing contrast sensitivity for binocular stimuli (sensBIN) with that measured in the good eye alone (sensGOOD), giving BSR = sensBIN/sensGOOD. This calculation provides an operational index of clinical binocular function, but does not assess whether neuronal m...

  10. Binocular eye movements in health and disease

    Science.gov (United States)

    Tyler, Christopher W.

    2013-03-01

    Binocular eye movements form a finely-tuned system that requires accurate coordination of the oculomotor dynamics and supports the vergence movements for tracking the fine binocular disparities required for 3D vision, and are particularly susceptible to disruption by brain injury and other neural dysfunctions. Saccadic dynamics for a population of 84 diverse participants show tight coefficients of variation of 2-10% of the mean value of each parameter. Significantly slower dynamics were seen for vertical upward saccades. Binocular coordination of saccades was accurate to within 1-4%, implying the operation of brainstem coordination mechanisms rather than independent cortical control of the two eyes. A new principle of oculomotor control - reciprocal binocular inhibition - is introduced to complement Sherrington's and Hering's Laws. This new law accounts for the fact that symmetrical vergence responses are about five times slower than saccades of the same amplitude, although a comprehensive analysis of asymmetrical vergence responses revealed unexpected variety in vergence dynamics. This analysis of the variety of human vergence responses thus contributes substantially to the understanding of the oculomotor control mechanisms underlying the generation of vergence movements and of the deficits in the oculomotor control resulting from mild traumatic brain injury.

  11. Night myopia is reduced in binocular vision.

    Science.gov (United States)

    Chirre, Emmanuel; Prieto, Pedro M; Schwarz, Christina; Artal, Pablo

    2016-06-01

    Night myopia, which is a shift in refraction with light level, has been widely studied but still lacks a complete understanding. We used a new infrared open-view binocular Hartmann-Shack wave front sensor to quantify night myopia under monocular and natural binocular viewing conditions. Both eyes' accommodative response, aberrations, pupil diameter, and convergence were simultaneously measured at light levels ranging from photopic to scotopic conditions to total darkness. For monocular vision, reducing the stimulus luminance resulted in a progression of the accommodative state that tends toward the subject's dark focus or tonic accommodation and a change in convergence following the induced accommodative error. Most subjects presented a myopic shift of accommodation that was mitigated in binocular vision. The impact of spherical aberration on the focus shift was relatively small. Our results in monocular conditions support the hypothesis that night myopia has an accommodative origin as the eye progressively changes its accommodation state with decreasing luminance toward its resting state in total darkness. On the other hand, binocularity restrains night myopia, possibly by using fusional convergence as an additional accommodative cue, thus reducing the potential impact of night myopia on vision at low light levels. PMID:27333457

  12. Motion Parallax is Asymptotic to Binocular Disparity

    CERN Document Server

    Stroyan, Keith

    2010-01-01

    Researchers especially beginning with (Rogers & Graham, 1982) have noticed important psychophysical and experimental similarities between the neurologically different motion parallax and stereopsis cues. Their quantitative analysis relied primarily on the "disparity equivalence" approximation. In this article we show that retinal motion from lateral translation satisfies a strong ("asymptotic") approximation to binocular disparity. This precise mathematical similarity is also practical in the sense that it applies at normal viewing distances. The approximation is an extension to peripheral vision of (Cormac & Fox's 1985) well-known non-trig central vision approximation for binocular disparity. We hope our simple algebraic formula will be useful in analyzing experiments outside central vision where less precise approximations have led to a number of quantitative errors in the vision literature.

  13. Trinocular Calibration Method Based on Binocular Calibration

    OpenAIRE

    CAO Dan-Dan; Luo, Chun; GAO Shu-Yuan; Wang, Yun; Li, Wen-Bin; XU Zhen-Ying

    2012-01-01

    In order to solve the self-occlusion problem in plane-based multi-camera calibration system and expand the measurement range, a tri-camera vision system based on binocular calibration is proposed. The three cameras are grouped into two pairs, while the public camera is taken as the reference to build the global coordinate. By calibration of the measured absolute distance and the true absolute distance, global calibration is realized. The MRE (mean relative error) of the global calibration of ...

  14. What is Grouping during Binocular Rivalry?

    OpenAIRE

    Sjoerd Martin Stuit; Chris ePaffen; Maarten evan der Smagt; Frans eVerstraten

    2011-01-01

    During binocular rivalry, perception alternates between dissimilar images presented dichoptically. Although perception during rivalry is believed to originate from competition at a local level, different rivalry zones are not independent: rival targets that are spaced apart but have similar features tend to be dominant at the same time. We investigated grouping of spatially separated rival targets presented to the same or to different eyes and presented in the same or in different hemifields....

  15. Quantum formalism to describe binocular rivalry.

    Science.gov (United States)

    Manousakis, Efstratios

    2009-11-01

    On the basis of the general character and operation of the process of perception, a formalism is sought to mathematically describe the subjective or abstract/mental process of perception. It is shown that the formalism of orthodox quantum theory of measurement, where the observer plays a key role, is a broader mathematical foundation which can be adopted to describe the dynamics of the subjective experience. The mathematical formalism describes the psychophysical dynamics of the subjective or cognitive experience as communicated to us by the subject. Subsequently, the formalism is used to describe simple perception processes and, in particular, to describe the probability distribution of dominance duration obtained from the testimony of subjects experiencing binocular rivalry. Using this theory and parameters based on known values of neuronal oscillation frequencies and firing rates, the calculated probability distribution of dominance duration of rival states in binocular rivalry under various conditions is found to be in good agreement with available experimental data. This theory naturally explains an observed marked increase in dominance duration in binocular rivalry upon periodic interruption of stimulus and yields testable predictions for the distribution of perceptual alteration in time. PMID:19520143

  16. When can attention influence binocular rivalry?

    Science.gov (United States)

    Dieter, Kevin C; Melnick, Michael D; Tadin, Duje

    2015-08-01

    Attentional influence over perception is particularly pronounced when sensory stimulation is ambiguous, where attention can reduce stimulus uncertainty and promote a stable interpretation of the world. However, binocular rivalry, an extensively studied visual ambiguity, has proved to be comparatively resistant to attentional modulation. We hypothesize that this apparent inconsistency reflects fluctuations in the degree of unresolved competition during binocular rivalry. Namely, attentional influence over rivalry dynamics should be limited to phases of relatively unresolved stimulus competition, such as ends of individual dominance periods. We found that transient, feature-based cues congruent with the dominant stimulus prolonged dominance durations, while cues matching the suppressed stimulus hastened its return to dominance. Notably, the effect of cues depended on when the cues are presented. Cues presented late, but not early, during a given episode of perceptual dominance influenced rivalry dynamics. This temporal pattern mirrors known changes in the relative competitive dynamics of rival stimuli, revealing that selective effects occur only during temporal windows containing weak resolution of visual competition. In conclusion, these findings reveal that unresolved competition, which gates attention across a variety of domains, is also crucial in determining the susceptibility of binocular rivalry to selective influences. PMID:25898898

  17. Target Image Matching Algorithm Based on Binocular CCD Ranging

    Directory of Open Access Journals (Sweden)

    Dongming Li

    2014-01-01

    Full Text Available This paper proposed target image in a subpixel level matching algorithm for binocular CCD ranging, which is based on the principle of binocular CCD ranging. In the paper, firstly, we introduced the ranging principle of the binocular ranging system and deduced a binocular parallax formula. Secondly, we deduced the algorithm which was named improved cross-correlation matching algorithm and cubic surface fitting algorithm for target images matched, and it could achieve a subpixel level matching for binocular CCD ranging images. Lastly, through experiment we have analyzed and verified the actual CCD ranging images, then analyzed the errors of the experimental results and corrected the formula of calculating system errors. Experimental results showed that the actual measurement accuracy of a target within 3 km was higher than 0.52%, which meet the accuracy requirements of the high precision binocular ranging.

  18. General binocular disorders: prevalence in a clinic population

    OpenAIRE

    Lara Lacarcel, Francisco; Cacho Martínez, Pilar; García Muñoz, Ángel; Megías, Ramón

    1999-01-01

    The purpose of this paper was to study the prevalence of nonstrabismic accommodative and binocular dysfunctions in a clinical population. We examined 265 symptomatic patients who were chosen from an optometric clinic. We performed several tests to diagnose any form of refractive, accommodative or binocular dysfunction. Of the 265 subjects examined, 59 patients (22.3%) had some form of accommodative or binocular dysfunction and required not just the correction of the refractive error but a spe...

  19. Randot stereoacuity at various binocular combinations of snellen acuity

    Directory of Open Access Journals (Sweden)

    Menon Vimala

    1997-01-01

    Full Text Available Binocular combinations of Snellen acuity were varied from 6/60 to 6/6 in standard steps in twenty normal adults and Randot stereoacuity was measured at each level. Using the 560 unique stereoacuity scores thus obtained, a nomogram was constructed which provides expected stereoacuity scores at all unique binocular combinations of Snellen acuity. It was seen that there is a linear correlation between binocular isoacuity (at level 6/36 or better and Randot stereoacuity.

  20. Maintaining a suite of binocular facility instruments at the Large Binocular Telescope

    Science.gov (United States)

    Reynolds, Robert O.; Morris, John; Power, Jennifer; Howard, James; Riedl, James; Solheid, Elliott; Wagner, R. M.; Veillet, Christian

    2014-08-01

    Facility Instruments at the Large Binocular Telescope (LBT) include the Large Binocular Camera (LBC), a pair of wide-field imagers at the prime focus, the LUCIFER (or LUCI) near-infrared imager and spectrograph pair, and the Multi-Object Double Spectrograph (MODS), a pair of long-slit spectrographs. The disciplines involved in instrument support are reviewed, as well as scheduling of support personnel. A computerized system for instrument maintenance scheduling and spare parts inventory is described. Instrument problems are tracked via an online reporting system, and statistics on types of instrument problems are discussed, as well as applicability of the system to troubleshooting.

  1. Ideal Binocular Disparity Detectors Learned Using Independent Subspace Analysis on Binocular Natural Image Pairs.

    Directory of Open Access Journals (Sweden)

    David W Hunter

    Full Text Available An influential theory of mammalian vision, known as the efficient coding hypothesis, holds that early stages in the visual cortex attempts to form an efficient coding of ecologically valid stimuli. Although numerous authors have successfully modelled some aspects of early vision mathematically, closer inspection has found substantial discrepancies between the predictions of some of these models and observations of neurons in the visual cortex. In particular analysis of linear-non-linear models of simple-cells using Independent Component Analysis has found a strong bias towards features on the horoptor. In order to investigate the link between the information content of binocular images, mathematical models of complex cells and physiological recordings, we applied Independent Subspace Analysis to binocular image patches in order to learn a set of complex-cell-like models. We found that these complex-cell-like models exhibited a wide range of binocular disparity-discriminability, although only a minority exhibited high binocular discrimination scores. However, in common with the linear-non-linear model case we found that feature detection was limited to the horoptor suggesting that current mathematical models are limited in their ability to explain the functionality of the visual cortex.

  2. Predictive Coding Explains Binocular Rivalry: An Epistemological Review

    Science.gov (United States)

    Hohwy, Jakob; Roepstorff, Andreas; Friston, Karl

    2008-01-01

    Binocular rivalry occurs when the eyes are presented with different stimuli and subjective perception alternates between them. Though recent years have seen a number of models of this phenomenon, the mechanisms behind binocular rivalry are still debated and we still lack a principled understanding of why a cognitive system such as the brain should…

  3. 3D Motion Parameters Determination Based on Binocular Sequence Images

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Exactly capturing three dimensional (3D) motion information of an object is an essential and important task in computer vision, and is also one of the most difficult problems. In this paper, a binocular vision system and a method for determining 3D motion parameters of an object from binocular sequence images are introduced. The main steps include camera calibration, the matching of motion and stereo images, 3D feature point correspondences and resolving the motion parameters. Finally, the experimental results of acquiring the motion parameters of the objects with uniform velocity and acceleration in the straight line based on the real binocular sequence images by the mentioned method are presented.

  4. Trinocular Calibration Method Based on Binocular Calibration

    Directory of Open Access Journals (Sweden)

    CAO Dan-Dan

    2012-10-01

    Full Text Available In order to solve the self-occlusion problem in plane-based multi-camera calibration system and expand the measurement range, a tri-camera vision system based on binocular calibration is proposed. The three cameras are grouped into two pairs, while the public camera is taken as the reference to build the global coordinate. By calibration of the measured absolute distance and the true absolute distance, global calibration is realized. The MRE (mean relative error of the global calibration of the two camera pairs in the experiments can be as low as 0.277% and 0.328% respectively. Experiment results show that this method is feasible, simple and effective, and has high precision.

  5. Practical considerations for pointing a binocular telescope

    Science.gov (United States)

    De La Peña, Michele D.; Terrett, David L.; Thompson, David; Biddick, Christopher J.

    2010-07-01

    The Large Binocular Telescope (LBT) consists of two 8.4-meter primary mirrors on a common mount. When the telescope is complete, to complement the two primaries there will be two 0.9-meter adaptive secondaries and two tertiary mirror flats that all work to support a variety of Gregorian focal stations, as well as prime focus. A fundamental goal of the telescope is to perform interferometric observations, and therefore, there is a critical need for the ability to co-point the individual telescopes to high precision. Further, a unique aspect of the LBT is the comparatively large range over which the optics can be adjusted which provides flexibility for the acquisition of targets. In the most general case, an observer could be performing an observation using different targets, within constraints, with different instruments on each of the two telescope sides, with different observing duty cycles. As a consequence of the binocular nature of the telescope and the number of possible observing combinations, there are unique requirements imposed on the Telescope Control System (TCS), and in particular, on the Pointing Control Subsystem (PCS). It is the responsibility of the PCS to arbitrate the pointing requests made on the two sides of the telescope by the observers, incorporate guide updates, and generate tracking trajectories for the mount and the rotators, in conjunction with providing tip/tilt demands on the subsystem controlling the optical elements, and ensure each target remains on the specified location (i.e., pointing origin) in the focal plane during an active observation. This paper describes the current design and implementation of the LBT PCS.

  6. HIERARCHICAL SPATIO-TEMPORAL DYNAMICS OF A CHAOTIC NEURAL NETWORK FOR MULTISTABLE BINOCULAR RIVALRY

    OpenAIRE

    KAKIMOTO, YUTA; Aihara, Kazuyuki

    2009-01-01

    Binocular rivalry is perceptual alternation that occurs when different visual images are presented to each eye. Despite the intensive studies, the mechanism of binocular rivalry still remains unclear. In multistable binocular rivalry, which is a special case of binocular rivalry, it is known that the perceptual alternation between paired patterns is more frequent than that between unpaired patterns. This result suggests that perceptual transition in binocular rivalry is not a simple random pr...

  7. Symptomatology associated with accommodative and binocular vision anomalies

    OpenAIRE

    García Muñoz, Ángel; Carbonell-Bonete, Stela; Cacho Martínez, Pilar

    2014-01-01

    Purpose: To determine the symptoms associated with accommodative and non-strabismic binocular dysfunctions and to assess the methods used to obtain the subjects’ symptoms. Methods: We conducted a scoping review of articles published between 1988 and 2012 that analysed any aspect of the symptomatology associated with accommodative and non-strabismic binocular dysfunctions. The literature search was performed in Medline (PubMed), CINAHL, PsycINFO and FRANCIS. A total of 657 articles were identi...

  8. What causes alternations in dominance during binocular rivalry?

    OpenAIRE

    Kang, Min-Suk; Blake, Randolph

    2010-01-01

    Several mechanisms have been proposed to account for perceptual alterations during binocular rivalry, including neural adaptation and neural noise. However, the importance of neural adaptation for producing perceptual alterations has been challenged in several articles (Y.-J. Kim, Grabowecky, & Suzuki, 2006; Moreno-Bote, Rinzel, & Rubin, 2007). We devised an “online” adaptation procedure to reexamine the role of adaptation in binocular rivalry. Periods of adaptation inserted into rivalry obse...

  9. A Model of Binocular Rivalry and Cross-orientation Suppression

    OpenAIRE

    Said, Christopher P.; Heeger, David J.

    2013-01-01

    Binocular rivalry and cross-orientation suppression are well-studied forms of competition in visual cortex, but models of these two types of competition are in tension with one another. Binocular rivalry occurs during the presentation of dichoptic grating stimuli, where two orthogonal gratings presented separately to the two eyes evoke strong alternations in perceptual dominance. Cross-orientation suppression occurs during the presentation of plaid stimuli, where the responses to a component ...

  10. Genetic contribution to individual variation in binocular rivalry rate

    OpenAIRE

    Miller, Steven M.; Hansell, Narelle K.; Ngo, Trung T.; Liu, Guang B.; Pettigrew, John D.; Martin, Nicholas G.; Wright, Margaret J.

    2010-01-01

    Binocular rivalry occurs when conflicting images are presented in corresponding locations of the two eyes. Perception alternates between the images at a rate that is relatively stable within individuals but that varies widely between individuals. The determinants of this variation are unknown. In addition, slow binocular rivalry has been demonstrated in bipolar disorder, a psychiatric condition with high heritability. The present study therefore examined whether there is a genetic contributio...

  11. The Role of Temporally Coarse Form Processing during Binocular Rivalry

    OpenAIRE

    van Boxtel, Jeroen J. A.; David Alais; Erkelens, Casper J.; Raymond van Ee

    2008-01-01

    Presenting the eyes with spatially mismatched images causes a phenomenon known as binocular rivalry-a fluctuation of awareness whereby each eye's image alternately determines perception. Binocular rivalry is used to study interocular conflict resolution and the formation of conscious awareness from retinal images. Although the spatial determinants of rivalry have been well-characterized, the temporal determinants are still largely unstudied. We confirm a previous observation that conflicting ...

  12. Perceptual constancy in judgments of egocentric distance: prevailing binocular information

    Directory of Open Access Journals (Sweden)

    Matsushima Elton H.

    2003-01-01

    Full Text Available Binocular cues were considered the prevailing information on specifying depth since the beginning of vision research. In the present study, two perceptual responses, the classical verbal report and a more recent method, open-loop walking, were used to assess the role of binocular information for egocentric distance perception. In two cue conditions environments, full- and reduced-cue, observers judged and walked egocentric distances of stimuli presented at eye-level, under binocular or monocular viewing. Results indicated perceptual constancy for open-loop walking and binocular responses, as well as poor performances under strong degradation on visual information (reduced-cue under monocular viewing, thus presenting evidence to support the fundamental role of binocular information on perception of egocentric distances. Besides that, visually directed actions could be adequate measures of perceived distance, with a better reliability than verbal report, since they were quite free of intrusion of inferential processes and perceptual tendencies. In addition, reduced head movements, side-to-side as well as back and forth deflexion movements, could have contributed to a near perfect coupling between binocular disparity information and open-loop walking responses.

  13. On the role of attention in binocular rivalry: electrophysiological evidence.

    Directory of Open Access Journals (Sweden)

    Urte Roeber

    Full Text Available During binocular rivalry visual consciousness fluctuates between two dissimilar monocular images. We investigated the role of attention in this phenomenon by comparing event-related potentials (ERPs when binocular-rivalry stimuli were attended with when they were unattended. Stimuli were dichoptic, orthogonal gratings that yielded binocular rivalry and dioptic, identically oriented gratings that yielded binocular fusion. Events were all possible orthogonal changes in orientation of one or both gratings. We had two attention conditions: In the attend-to-grating condition, participants had to report changes in perceived orientation, focussing their attention on the gratings. In the attend-to-fixation condition participants had to report changes in a central fixation target, taking attention away from the gratings. We found, surprisingly, that attending to rival gratings yielded a smaller ERP component (the N1, from 160-210 ms than attending to the fixation target. To explain this paradoxical effect of attention, we propose that rivalry occurs in the attend-to-fixation condition (we found an ERP signature of rivalry in the form of a sustained negativity from 210-300 ms but that the mechanism processing the stimulus changes is more adapted in the attend-to-grating condition than in the attend-to-fixation condition. This is consistent with the theory that adaptation gives rise to changes of visual consciousness during binocular rivalry.

  14. 'Proto-rivalry': how the binocular brain identifies gloss.

    Science.gov (United States)

    Muryy, Alexander A; Fleming, Roland W; Welchman, Andrew E

    2016-05-11

    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. PMID:27170713

  15. ‘Proto-rivalry’: how the binocular brain identifies gloss

    Science.gov (United States)

    Muryy, Alexander A.; Welchman, Andrew E.

    2016-01-01

    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. PMID:27170713

  16. Acute Alcohol Drinking Promotes Piecemeal Percepts during Binocular Rivalry.

    Science.gov (United States)

    Cao, Dingcai; Zhuang, Xiaohua; Kang, Para; Hong, Sang W; King, Andrea C

    2016-01-01

    Binocular rivalry refers to perceptual alternation when two eyes view different images. One of the potential percepts during binocular rivalry is a spatial mosaic of left- and right-eye images, known as piecemeal percepts, which may result from localized rivalries between small regions in the left- and right-eye images. It is known that alcohol increases inhibitory neurotransmission, which may reduce the number of alternations during binocular rivalry. However, it is unclear whether alcohol affects rivalry dynamics in the same manner for both coherent percepts (i.e., percepts of complete left or right images) and piecemeal percepts. To address this question, the present study measured the dynamics of binocular rivalry before and after 15 moderate-to-heavy social drinkers consumed an intoxicating dose of alcohol versus a placebo beverage. Both simple rivalrous stimuli consisting of gratings with different orientations, and complex stimuli consisting of a face or a house were tested to examine alcohol effects on rivalry as a function of stimulus complexity. Results showed that for both simple and complex stimuli, alcohol affects coherent and piecemeal percepts differently. More specifically, alcohol reduced the number of coherent percepts but not the mean dominance duration of coherent percepts. In contrast, for piecemeal percepts, alcohol increased the mean dominance duration but not the number of piecemeal percepts. These results suggested that alcohol drinking may selectively affect the dynamics of transitional period of binocular rivalry by increasing the duration of piecemeal percepts, leading to a reduction in the number of coherent percepts. The differential effect of alcohol on the dynamics of coherent and piecemeal percepts cannot be accounted for by alcohol's effect on a common inhibitory mechanism. Other mechanisms, such as increasing neural noise, are needed to explain alcohol's effect on the dynamics of binocular rivalry. PMID:27092096

  17. Acute Alcohol Drinking Promotes Piecemeal Percepts during Binocular Rivalry

    Science.gov (United States)

    Cao, Dingcai; Zhuang, Xiaohua; Kang, Para; Hong, Sang W.; King, Andrea C.

    2016-01-01

    Binocular rivalry refers to perceptual alternation when two eyes view different images. One of the potential percepts during binocular rivalry is a spatial mosaic of left- and right-eye images, known as piecemeal percepts, which may result from localized rivalries between small regions in the left- and right-eye images. It is known that alcohol increases inhibitory neurotransmission, which may reduce the number of alternations during binocular rivalry. However, it is unclear whether alcohol affects rivalry dynamics in the same manner for both coherent percepts (i.e., percepts of complete left or right images) and piecemeal percepts. To address this question, the present study measured the dynamics of binocular rivalry before and after 15 moderate-to-heavy social drinkers consumed an intoxicating dose of alcohol versus a placebo beverage. Both simple rivalrous stimuli consisting of gratings with different orientations, and complex stimuli consisting of a face or a house were tested to examine alcohol effects on rivalry as a function of stimulus complexity. Results showed that for both simple and complex stimuli, alcohol affects coherent and piecemeal percepts differently. More specifically, alcohol reduced the number of coherent percepts but not the mean dominance duration of coherent percepts. In contrast, for piecemeal percepts, alcohol increased the mean dominance duration but not the number of piecemeal percepts. These results suggested that alcohol drinking may selectively affect the dynamics of transitional period of binocular rivalry by increasing the duration of piecemeal percepts, leading to a reduction in the number of coherent percepts. The differential effect of alcohol on the dynamics of coherent and piecemeal percepts cannot be accounted for by alcohol’s effect on a common inhibitory mechanism. Other mechanisms, such as increasing neural noise, are needed to explain alcohol’s effect on the dynamics of binocular rivalry. PMID:27092096

  18. A new apparatus for visual field testing with binocular fixation

    Directory of Open Access Journals (Sweden)

    Hasegawa,Eiichi

    1978-07-01

    Full Text Available A new instrument for visual field examination with binocular fixation is described. The binocular vision was dissociated with polarizing plates. Only the point of fixation was visible to both eyes while the testing chart (Amsler chart was visible to one eye in the use of this apparatus. The examination was done with both the patient's eyes open. With the use of this apparatus, not only was the visual line fixed steadily in order to detect various changes of the central visual field due to maculopathy or optic neuropathy and these changes were detected accurately and quickly, but also suppression scotoma associated with amblyopia or squint could be detected quantitatively.

  19. An integrated framework of spatiotemporal dynamics of binocular rivalry

    OpenAIRE

    Min-Suk Kang; Randolph Blake

    2011-01-01

    Fluctuations in perceptual dominance during binocular rivalry exhibit several hallmark characteristics. First, dominance switches are not periodic but, instead, stochastic: perception changes unpredictably. Second, despite being stochastic, average durations of rivalry dominance vary dependent on the strength of the rival stimuli: variations in contrast, luminance or spatial frequency produce predictable changes in average dominance durations and, hence, in alternation rate. Third, perceptual...

  20. The 'laws' of binocular rivalry: 50 years of Levelt's propositions.

    Science.gov (United States)

    Brascamp, J W; Klink, P C; Levelt, W J M

    2015-04-01

    It has been fifty years since Levelt's monograph On Binocular Rivalry (1965) was published, but its four propositions that describe the relation between stimulus strength and the phenomenology of binocular rivalry remain a benchmark for theorists and experimentalists even today. In this review, we will revisit the original conception of the four propositions and the scientific landscape in which this happened. We will also provide a brief update concerning distributions of dominance durations, another aspect of Levelt's monograph that has maintained a prominent presence in the field. In a critical evaluation of Levelt's propositions against current knowledge of binocular rivalry we will then demonstrate that the original propositions are not completely compatible with what is known today, but that they can, in a straightforward way, be modified to encapsulate the progress that has been made over the past fifty years. The resulting modified, propositions are shown to apply to a broad range of bistable perceptual phenomena, not just binocular rivalry, and they allow important inferences about the underlying neural systems. We argue that these inferences reflect canonical neural properties that play a role in visual perception in general, and we discuss ways in which future research can build on the work reviewed here to attain a better understanding of these properties. PMID:25749677

  1. An Integrated Framework of Spatiotemporal Dynamics of Binocular Rivalry

    OpenAIRE

    Kang, Min-Suk; Blake, Randolph

    2011-01-01

    Fluctuations in perceptual dominance during binocular rivalry exhibit several hallmark characteristics. First, dominance switches are not periodic but, instead, stochastic: perception changes unpredictably. Second, despite being stochastic, average durations of rivalry dominance vary dependent on the strength of the rival stimuli: variations in contrast, luminance, or spatial frequency produce predictable changes in average dominance durations and, hence, in alternation rate. Third, perceptua...

  2. Symbolic Magnitude Modulates Perceptual Strength in Binocular Rivalry

    Science.gov (United States)

    Paffen, Chris L. E.; Plukaard, Sarah; Kanai, Ryota

    2011-01-01

    Basic aspects of magnitude (such as luminance contrast) are directly represented by sensory representations in early visual areas. However, it is unclear how symbolic magnitudes (such as Arabic numerals) are represented in the brain. Here we show that symbolic magnitude affects binocular rivalry: perceptual dominance of numbers and objects of…

  3. Predictive context influences perceptual selection during binocular rivalry

    Directory of Open Access Journals (Sweden)

    Rachel N Denison

    2011-12-01

    Full Text Available Prediction may be a fundamental principle of sensory processing: it has been proposed that the brain continuously generates predictions about forthcoming sensory information. However, little is known about how prediction contributes to the selection of a conscious percept from among competing alternatives. Here, we used binocular rivalry to investigate the effects of prediction on perceptual selection. In binocular rivalry, incompatible images presented to the two eyes result in a perceptual alternation between the images, even though the visual stimuli remain constant. If predictive signals influence the competition between neural representations of rivalrous images, this influence should generate a bias in perceptual selection that depends on predictive context. To manipulate predictive context, we developed a novel binocular rivalry paradigm in which rivalrous test images were immediately preceded by a sequence of context images presented identically to the two eyes. One of the test images was consistent with the preceding image sequence (it was the expected next image in the series, and the other was inconsistent (non-predicted. We found that human observers were more likely to perceive the consistent image at the onset of rivalry, suggesting that predictive context biased selection in favor of the predicted percept. This prediction effect was distinct from the effects of adaptation to stimuli presented before the binocular rivalry test. In addition, perceptual reports were speeded for predicted percepts relative to non-predicted percepts. These results suggest that predictive signals related to visual stimulus history exist at neural sites that can bias conscious perception during binocular rivalry. Our paradigm provides a new way to study how prior information and incoming sensory information combine to generate visual percepts.

  4. Training of binocular rivalry suppression suggests stimulus-specific plasticity in monocular and binocular visual areas.

    Science.gov (United States)

    Vergeer, Mark; Wagemans, Johan; van Ee, Raymond

    2016-01-01

    The plasticity of the human brain, as shown in perceptual learning, is generally reflected by improved task performance after training. Here, we show that perceptual suppression can be increased through training. In the first experiment, binocular rivalry suppression of a specific orientation was trained, leading to a relative reduction in sensitivity to the trained orientation. In a second experiment, two orthogonal orientations were suppressed in alternating training blocks, in the left and right eye, respectively. This double-training procedure lead to reduced sensitivity for the orientation that was suppression-trained in each specific eye, implying that training of feature suppression is specific for the eye in which the oriented grating was presented during training. Results of a control experiment indicate that the obtained effects are indeed due to suppression during training, instead of being merely due to the repetitive presentation of the oriented gratings. Visual plasticity is essential for a person's visual development. The finding that plasticity can result in increased perceptual suppression reported here may prove to be significant in understanding human visual development. It emphasizes that for stable vision, not only the enhancement of relevant signals is crucial, but also the reliable and stable suppression of (task) irrelevant signals. PMID:27160838

  5. MONOCULAR AND BINOCULAR VISION IN THE PERFORMANCE OF A COMPLEX SKILL

    Directory of Open Access Journals (Sweden)

    Thomas Heinen

    2011-09-01

    Full Text Available The goal of this study was to investigate the role of binocular and monocular vision in 16 gymnasts as they perform a handspring on vault. In particular we reasoned, if binocular visual information is eliminated while experts and apprentices perform a handspring on vault, and their performance level changes or is maintained, then such information must or must not be necessary for their best performance. If the elimination of binocular vision leads to differences in gaze behavior in either experts or apprentices, this would answer the question of an adaptive gaze behavior, and thus if this is a function of expertise level or not. Gaze behavior was measured using a portable and wireless eye-tracking system in combination with a movement-analysis system. Results revealed that gaze behavior differed between experts and apprentices in the binocular and monocular conditions. In particular, apprentices showed less fixations of longer duration in the monocular condition as compared to experts and the binocular condition. Apprentices showed longer blink duration than experts in both, the monocular and binocular conditions. Eliminating binocular vision led to a shorter repulsion phase and a longer second flight phase in apprentices. Experts exhibited no differences in phase durations between binocular and monocular conditions. Findings suggest, that experts may not rely on binocular vision when performing handsprings, and movement performance maybe influenced in apprentices when eliminating binocular vision. We conclude that knowledge about gaze-movement relationships may be beneficial for coaches when teaching the handspring on vault in gymnastics

  6. Binocular disparity as an explanation for the moon illusion

    CERN Document Server

    Antonides, Joseph

    2013-01-01

    We present another explanation for the moon illusion, in which the moon looks larger near the horizon than near the zenith. In our model, the sky is considered a spatially contiguous and geometrically smooth surface. When an object (like the moon) breaks the contiguity of the surface, humans perceive an occlusion of the surface rather than an object appearing through a hole. Binocular vision dictates that the moon is distant, but this perception model dictates that the moon is closer than the sky. To solve the dilemma, the brain distorts the projections of the moon to increase the binocular disparity, which results in increase of the angular size of the moon. The degree of the distortion depends upon the apparent distance to the sky, which is influenced by the surrounding objects and the condition of the sky. The closer the sky appears, the stronger the illusion. At the zenith, few distance cues are present, causing difficulty with distance estimation and weakening the illusion.

  7. An integrated framework of spatiotemporal dynamics of binocular rivalry

    Directory of Open Access Journals (Sweden)

    Min-Suk Kang

    2011-08-01

    Full Text Available Fluctuations in perceptual dominance during binocular rivalry exhibit several hallmark characteristics. First, dominance switches are not periodic but, instead, stochastic: perception changes unpredictably. Second, despite being stochastic, average durations of rivalry dominance vary dependent on the strength of the rival stimuli: variations in contrast, luminance or spatial frequency produce predictable changes in average dominance durations and, hence, in alternation rate. Third, perceptual switches originate locally and spread globally over time, sometimes as traveling waves of dominance: rivalry transitions are spatio-temporal events. This essay 1 reviews recent advances in our understanding of the bases of these three hallmark characteristics of binocular rivalry dynamics and 2 provides an integrated framework to account for those dynamics using cooperative and competitive spatial interactions among local neural circuits distributed over the visual field’s retinotopic map. We close with speculations about how that framework might incorporate top-down influences on rivalry dynamics.

  8. Binocular rivalry alternations and their relation to visual adaptation

    OpenAIRE

    Daphne eRoumani; Konstantinos eMoutoussis

    2012-01-01

    When different stimuli are presented dichoptically, perception alternates between the two in a stochastic manner. After a long-lasting and rigorous debate, there is growing consensus that this phenomenon, known as binocular rivalry, is the result of a dynamic competition occurring at multiple levels of the visual hierarchy. The role of low- and high-level adaptation mechanisms in controlling these perceptual alternations has been a key issue in the rivalry literature. Both types of adaptatio...

  9. Standard Test Method for Measuring Binocular Disparity in Transparent Parts

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers the amount of binocular disparity that is induced by transparent parts such as aircraft windscreens, canopies, HUD combining glasses, visors, or goggles. This test method may be applied to parts of any size, shape, or thickness, individually or in combination, so as to determine the contribution of each transparent part to the overall binocular disparity present in the total “viewing system” being used by a human operator. 1.2 This test method represents one of several techniques that are available for measuring binocular disparity, but is the only technique that yields a quantitative figure of merit that can be related to operator visual performance. 1.3 This test method employs apparatus currently being used in the measurement of optical angular deviation under Method F 801. 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not con...

  10. Binocular interactions underlying the classic optomotor responses of flying flies

    Directory of Open Access Journals (Sweden)

    Mark A Frye

    2012-02-01

    Full Text Available In response to imposed course deviations, the fast optomotor reactions of animals reduce motion blur and facilitate the maintenance of stable body posture. In flies, the monocular front-to-back (progressive and back-to-front (regressive visual motion components generated by horizontal rotation are selectively encoded, respectively, by homo and heterolateral motion sensitive circuits in the third optic ganglion, the lobula plate. To investigate the strength of such inter-ocular interactions and their role in compensatory sensory-motor transformations, we utilize a virtual reality flight simulator to record optomotor reactions by tethered flying flies in response to imposed binocular and monocular visual rotation. With stimulus parameters generating large contrast insensitive optomotor responses to binocular rotation, we find that responses to monocular progressive motion are larger than those to panoramic rotation but contrast sensitive. Conversely, responses to monocular regressive motion are slower than those to rotation and peak at the lowest tested contrast. Together our results suggest that contrast insensitive optomotor responses to binocular rotation result from the dynamic interplay of contralateral inhibitory as well as excitatory circuit interactions and serve to maintain a stable optomotor equilibrium across a range of visual contrasts.

  11. Binocular Rivalry in a Competitive Neural Network with Synaptic Depression

    KAUST Repository

    Kilpatrick, Zachary P.

    2010-01-01

    We study binocular rivalry in a competitive neural network with synaptic depression. In particular, we consider two coupled hypercolums within primary visual cortex (V1), representing orientation selective cells responding to either left or right eye inputs. Coupling between hypercolumns is dominated by inhibition, especially for neurons with dissimilar orientation preferences. Within hypercolumns, recurrent connectivity is excitatory for similar orientations and inhibitory for different orientations. All synaptic connections are modifiable by local synaptic depression. When the hypercolumns are driven by orthogonal oriented stimuli, it is possible to induce oscillations that are representative of binocular rivalry. We first analyze the occurrence of oscillations in a space-clamped version of the model using a fast-slow analys is, taking advantage of the fact that depression evolves much slower than population activity. We th en analyze the onset of oscillations in the full spatially extended system by carrying out a piecewise smooth stability analysis of single (winner-take-all) and double (fusion) bumps within the network. Although our stability analysis takes into account only instabilities associated with real eigenvalues, it identifies points of instability that are consistent with what is found numerically. In particular, we show that, in regions of parameter space where double bumps are unstable and no single bumps exist, binocular rivalry can arise as a slow alternation between either population supporting a bump. © 2010 Society for Industrial and Applied Mathematics.

  12. A Standardized Procedure and Normative Values for Measuring Binocular Dynamic Visual Acuity

    OpenAIRE

    Amanda Miskewicz-Zastrow, OD; Eric Bishop, OD; Alan Zastrow, OD; Dan Mark Cuevas, OD; Bill B. Rainey, OD, MS

    2015-01-01

    Background: Binocular dynamic visual acuity (BDVA) is the ability to differentiate fine details in a moving object such as seams on a pitched baseball or the rotation of a tennis ball, both of which can travel up to speeds exceeding 100 miles per hour. BDVA is one of many binocular visual measurements to examine binocular function. This study was designed to provide a standardized procedure for measuring BDVA and normal values for a sample population. Previous studies have used different t...

  13. Anomalies of binocular function in patients with longstanding asymmetric keratoconus

    OpenAIRE

    Sherafat, H; White, J; Pullum, K.; Adams, G; Sloper, J.

    2001-01-01

    AIMS—To study binocular function in patients with longstanding asymmetric keratoconus.
METHODS—In 20 adult patients with longstanding asymmetric keratoconus managed with a scleral contact lens a full clinical and orthoptic assessment was performed with and without the scleral contact lens in the poorer eye.
RESULTS—All 20 patients had a corrected acuity of at least 6/9 in their better eye. With the scleral lens in situ the acuity of the poorer eye ranged from 6/6 to 6/60 and without the lens ...

  14. An automated miniaturized Haploscope for testing binocular visual function

    Science.gov (United States)

    Decker, T. A.; Williams, R. E.; Kuether, C. L.; Wyman-Cornsweet, D.

    1976-01-01

    A computer-controlled binocular vision testing device has been developed as one part of a system designed for NASA to test the vision of astronauts during spaceflight. The device, called the Mark III Haploscope, utilizes semi-automated psychophysical test procedures to measure visual acuity, stereopsis, phorias, fixation disparity and accommodation/convergence relationships. All tests are self-administered, yield quantitative data and may be used repeatedly without subject memorization. Future applications of this programmable, compact device include its use as a clinical instrument to perform routine eye examinations or vision screening, and as a research tool to examine the effects of environment or work-cycle upon visual function.

  15. A Buyer's and User's Guide to Astronomical Telescopes and Binoculars

    Science.gov (United States)

    Mullaney, James

    This book is offered as a no-nonsense practical guide to the selection and use of telescopes and binoculars for stargazing. But these devices should not be looked upon as yet more gadgets to add to our collection of modern technical possessions. Rightly viewed, they are truly magical instruments, for they are literally "spaceships of the mind," "time machines," and "windows on creation" that allow their users to roam the universe in what is surely the next best thing to actually being there!

  16. The future of binocular rivalry research: reaching through a window on consciousness

    NARCIS (Netherlands)

    Klink, P. Christiaan; Wezel, van Richard J.A.; Ee, van Raymond; Miller, Steven M.

    2013-01-01

    Binocular rivalry is often considered an experimental window on the neural processes of consciousness. We propose three distinct approaches to exploit this window. First, one may look through the window, using binocular rivalry as a passive tool to dissociate unaltered sensory input from wavering pe

  17. Individual differences in the temporal dynamics of binocular rivalry and stimulus rivalry

    NARCIS (Netherlands)

    Patel, Vaama; Stuit, Sjoerd; Blake, Randolph

    2015-01-01

    Binocular rivalry and stimulus rivalry are two forms of perceptual instability that arise when the visual system is confronted with conflicting stimulus information. In the case of binocular rivalry, dissimilar monocular stimuli are presented to the two eyes for an extended period of time, whereas f

  18. Evaluation of Binocular Vision Therapy Efficacy by 3D Video-Oculography Measurement of Binocular Alignment and Motility

    OpenAIRE

    Laria Ochaíta, Carlos; Piñero Llorens, David Pablo

    2013-01-01

    Objective: To evaluate two cases of intermittent exotropia (IX(T)) treated by vision therapy the efficacy of the treatment by complementing the clinical examination with a 3-D video-oculography to register and to evidence the potential applicability of this technology for such purpose. Methods: We report the binocular alignment changes occurring after vision therapy in a woman of 36 years with an IX(T) of 25 prism diopters (Δ) at far and 18 Δ at near and a child of 10 years with 8 Δ of IX(T) ...

  19. Remote landslide mapping using a laser rangefinder binocular and GPS

    Directory of Open Access Journals (Sweden)

    M. Santangelo

    2010-12-01

    Full Text Available We tested a high-quality laser rangefinder binocular coupled with a GPS receiver connected to a Tablet PC running dedicated software to help recognize and map in the field recent rainfall-induced landslides. The system was tested in the period between March and April 2010, in the Monte Castello di Vibio area, Umbria, Central Italy. To test the equipment, we measured thirteen slope failures that were mapped previously during a visual reconnaissance field campaign conducted in February and March 2010. For reference, four slope failures were also mapped by walking the GPS receiver along the landslide perimeter. Comparison of the different mappings revealed that the geographical information obtained remotely for each landslide by the rangefinder binocular and GPS was comparable to the information obtained by walking the GPS around the landslide perimeter, and was superior to the information obtained through the visual reconnaissance mapping. Although our tests were not exhaustive, we maintain that the system is effective to map recent rainfall induced landslides in the field, and we foresee the possibility of using the same (or similar system to map landslides, and other geomorphological features, in other areas.

  20. Status and Plans for the Large Binocular Telescope

    Science.gov (United States)

    Green, R. F.

    2006-08-01

    The Large Binocular Telescope (LBT) is in commissioning, with the initiation of science operations planned for 2007. The telescope contains two 8.4-m diameter borosilicate honeycomb primary mirrors, supported actively to control bending modes. The secondary mirrors will provide adaptive optics correction through rapid modulation of the surface of a Zerodur face sheet 91 cm in diameter and 1.5 mm thick. The initial complement of facility instruments comprises capabilities used in pairs on common fields of view. The Large Binocular Cameras are wide-field 36 Mpix mosaics at prime focus optimized for blue and for red performance. The Multi-Object Double Spectrographs will be fed at straight-through Gregorian foci through custom cut focal plane masks. The ambitious LUCIFER near-IR spectrographs at bent Gregorian will have exchangeable cold focal plan masks. Ultimately, two instruments will combine the two beams through Fizeau interferometry. One, LBTI, is optimized for mid-IR, and will have a nulling capability for coronagraphic work. The other, LINC-NIRVANA, will employ three levels of adaptive correction to achieve interferometric resolution down to 1 micron. The 23-m tip-to-tip dimension affords resolution as good as 10 mas. LBTO is supported by a consortium of institutions from Arizona, Italy, Germany, and the U.S. It is truly an international project and the first of the next generation of large ground-based telescopes.

  1. Motion dominance in binocular rivalry depends on extraretinal motions.

    Science.gov (United States)

    Nakayama, Ryohei; Motoyoshi, Isamu; Sato, Takao

    2016-01-01

    In binocular rivalry, moving stimulus is dominant over stationary stimulus. This is called motion dominance. The motion here is usually a motion defined on the retina (retinal motion). However, motion can be defined in several different coordinates. It can be defined with respect to objects in the background (object-based motion) or to observers' head or body (spatiotopic motion), as well as to the retinal coordinate. In this study, we examined the role of motions defined by these three coordinates. A dichoptic pair of gratings was presented to create a binocular rivalry, one of which was moving and the other stationary. A fixation point and a reference background were either moving with the grating or stationary, depending on the condition. Different combinations of the three types of motions were created by having the observer track the fixation point or the background when they are moving. It was found that the retinal motion does not necessarily yield motion dominance, and that the motion dominance is determined by the combination of motions defined by different coordinate systems. PMID:26943347

  2. Bistable percepts in the brain: FMRI contrasts monocular pattern rivalry and binocular rivalry.

    Directory of Open Access Journals (Sweden)

    Athena Buckthought

    Full Text Available The neural correlates of binocular rivalry have been actively debated in recent years, and are of considerable interest as they may shed light on mechanisms of conscious awareness. In a related phenomenon, monocular rivalry, a composite image is shown to both eyes. The subject experiences perceptual alternations in which the two stimulus components alternate in clarity or salience. The experience is similar to perceptual alternations in binocular rivalry, although the reduction in visibility of the suppressed component is greater for binocular rivalry, especially at higher stimulus contrasts. We used fMRI at 3T to image activity in visual cortex while subjects perceived either monocular or binocular rivalry, or a matched non-rivalrous control condition. The stimulus patterns were left/right oblique gratings with the luminance contrast set at 9%, 18% or 36%. Compared to a blank screen, both binocular and monocular rivalry showed a U-shaped function of activation as a function of stimulus contrast, i.e. higher activity for most areas at 9% and 36%. The sites of cortical activation for monocular rivalry included occipital pole (V1, V2, V3, ventral temporal, and superior parietal cortex. The additional areas for binocular rivalry included lateral occipital regions, as well as inferior parietal cortex close to the temporoparietal junction (TPJ. In particular, higher-tier areas MT+ and V3A were more active for binocular than monocular rivalry for all contrasts. In comparison, activation in V2 and V3 was reduced for binocular compared to monocular rivalry at the higher contrasts that evoked stronger binocular perceptual suppression, indicating that the effects of suppression are not limited to interocular suppression in V1.

  3. Natural Tendency towards Beauty in Humans: Evidence from Binocular Rivalry.

    Science.gov (United States)

    Mo, Ce; Xia, Tiansheng; Qin, Kaixin; Mo, Lei

    2016-01-01

    Although human preference for beauty is common and compelling in daily life, it remains unknown whether such preference is essentially subserved by social cognitive demands or natural tendency towards beauty encoded in the human mind intrinsically. Here we demonstrate experimentally that humans automatically exhibit preference for visual and moral beauty without explicit cognitive efforts. Using a binocular rivalry paradigm, we identified enhanced gender-independent perceptual dominance for physically attractive persons, and the results suggested universal preference for visual beauty based on perceivable forms. Moreover, we also identified perceptual dominance enhancement for characters associated with virtuous descriptions after controlling for facial attractiveness and vigilance-related attention effects, which suggested a similar implicit preference for moral beauty conveyed in prosocial behaviours. Our findings show that behavioural preference for beauty is driven by an inherent natural tendency towards beauty in humans rather than explicit social cognitive processes. PMID:26930202

  4. Natural Tendency towards Beauty in Humans: Evidence from Binocular Rivalry.

    Directory of Open Access Journals (Sweden)

    Ce Mo

    Full Text Available Although human preference for beauty is common and compelling in daily life, it remains unknown whether such preference is essentially subserved by social cognitive demands or natural tendency towards beauty encoded in the human mind intrinsically. Here we demonstrate experimentally that humans automatically exhibit preference for visual and moral beauty without explicit cognitive efforts. Using a binocular rivalry paradigm, we identified enhanced gender-independent perceptual dominance for physically attractive persons, and the results suggested universal preference for visual beauty based on perceivable forms. Moreover, we also identified perceptual dominance enhancement for characters associated with virtuous descriptions after controlling for facial attractiveness and vigilance-related attention effects, which suggested a similar implicit preference for moral beauty conveyed in prosocial behaviours. Our findings show that behavioural preference for beauty is driven by an inherent natural tendency towards beauty in humans rather than explicit social cognitive processes.

  5. A Novel Approach to Calibrating Multifunctional Binocular Stereovision Sensor

    International Nuclear Information System (INIS)

    We present a novel multifunctional binocular stereovision sensor for various threedimensional (3D) inspection tasks. It not only avoids the so-called correspondence problem of passive stereo vision, but also possesses the uniform mathematical model. We also propose a novel approach to estimating all the sensor parameters with free-position planar reference object. In this technique, the planar pattern can be moved freely by hand. All the camera intrinsic and extrinsic parameters with coefficient of lens radial and tangential distortion are estimated, and sensor parameters are calibrated based on the 3D measurement model and optimized with the feature point constraint algorithm using the same views in the camera calibration stage. The proposed approach greatly reduces the cost of the calibration equipment, and it is flexible and practical for the vision measurement. It shows that this method has high precision by experiment, and the sensor measured relative error of space length excels 0.3%

  6. Effect of firefighter masks on monocular and binocular peripheral vision.

    Science.gov (United States)

    Samo, Daniel G; Bahk, Jane K; Gerkin, Richard D

    2003-04-01

    Peripheral vision can impact essential job functions of firefighters and other workers who use Self-Contained Breathing Apparatus and other full face masks. It is important for physicians to know how these masks alter peripheral vision. Also, one must understand the effect of monocular vision on peripheral vision. Using the Goldman Perimeter Machine we measured peripheral vision in the monocular and binocular state, with and without two different types of masks. The results show that monocularity causes an average loss of 23 degrees in the nasal meridian. The use of the masks did not affect this difference. Also, the masks caused an average loss of 28 degrees of peripheral vision in the inferior meridian. How these losses affect the ability of the users of the masks to perform their essential job functions still needs to be researched. PMID:12708146

  7. Natural Tendency towards Beauty in Humans: Evidence from Binocular Rivalry

    Science.gov (United States)

    Mo, Lei

    2016-01-01

    Although human preference for beauty is common and compelling in daily life, it remains unknown whether such preference is essentially subserved by social cognitive demands or natural tendency towards beauty encoded in the human mind intrinsically. Here we demonstrate experimentally that humans automatically exhibit preference for visual and moral beauty without explicit cognitive efforts. Using a binocular rivalry paradigm, we identified enhanced gender-independent perceptual dominance for physically attractive persons, and the results suggested universal preference for visual beauty based on perceivable forms. Moreover, we also identified perceptual dominance enhancement for characters associated with virtuous descriptions after controlling for facial attractiveness and vigilance-related attention effects, which suggested a similar implicit preference for moral beauty conveyed in prosocial behaviours. Our findings show that behavioural preference for beauty is driven by an inherent natural tendency towards beauty in humans rather than explicit social cognitive processes. PMID:26930202

  8. Origins of strabismus and loss of binocular vision

    Directory of Open Access Journals (Sweden)

    Emmanuel Bui Quoc

    2014-09-01

    Full Text Available Strabismus is a frequent ocular disorder that develops early in life in humans. As a general rule, it is characterized by a misalignment of the visual axes which most often appears during the critical period of visual development. However other characteristics of strabismus may vary greatly among subjects, for example, being convergent or divergent, horizontal or vertical, with variable angles of deviation. Binocular vision may also vary greatly. Our main goal here is to develop the idea that such “polymorphy” reflects a wide variety in the possible origins of strabismus. We propose that strabismus must be considered as possibly resulting from abnormal genetic and/or acquired factors, anatomical and/or functional abnormalities, in the sensory and/or the motor systems, both peripherally and/or in the brain itself. We shall particularly develop the possible “central” origins of strabismus. Indeed, we are convinced that it is time now to open this “black box” in order to move forward. All of this will be developed on the basis of both presently available data in literature (including most recent data and our own experience. Both data in medicine and biology will be referred to. Our conclusions will hopefully help ophthalmologists to better understand strabismus and to develop new therapeutic strategies in the future. Presently, physicians eliminate or limit the negative effects of such pathology both on the development of the visual system and visual perception through the use of optical correction and, in some cases, extraocular muscle surgery. To better circumscribe the problem of the origins of strabismus, including at a cerebral level, may improve its management, in particular with respect to binocular vision, through innovating tools by treating the pathology at the source.

  9. Robust Active Binocular Vision through Intrinsically Motivated Learning

    Directory of Open Access Journals (Sweden)

    Luca eLonini

    2013-11-01

    Full Text Available The efficient coding hypothesis posits that sensory systems of animals strive to encode sensory signals efficiently by taking into account the redundancies in them. This principle has been very successful in explaining response properties of visual sensory neurons as adaptations to the statistics of natural images. Recently, we have begun to extend the efficient coding hypothesis to active perception through a form of intrinsically motivated learning: a sensory model learns an efficient code for the sensory signals while a reinforcement learner generates movements of the sense organs to improve the encoding of the signals. To this end, it receives an intrinsically generated reinforcement signal indicating how well the sensory model encodes the data. This approach has been tested in the context of binocular vison, leading to the autonomous development of disparity tuning and vergence control. Here we systematically investigate the robustness of the new approach in the context of a binocular vision system implemented on a robot. Robustness is an important aspect that reflects the ability of the system to deal with unmodeled disturbances or events, such as an insult to the system that displace the stereo cameras. To demonstrate the robustness of our method and its ability to self-calibrate, we introduce various perturbations and test if and how the system recovers from them. We find that 1 the system can fully recover from a perturbation that can be compensated through the system's motor degrees of freedom, 2 performance degrades gracefully if the system cannot use its motor degrees of freedom to compensate for the perturbation, and 3 recovery from a perturbation is improved if both the sensory encoding and the behavior policy can adapt to the perturbation. Overall, this work demonstrates that our intrinsically motivated learning approach for efficient coding in active perception gives rise to a self-calibrating perceptual system of high robustness.

  10. Robust active binocular vision through intrinsically motivated learning.

    Science.gov (United States)

    Lonini, Luca; Forestier, Sébastien; Teulière, Céline; Zhao, Yu; Shi, Bertram E; Triesch, Jochen

    2013-01-01

    The efficient coding hypothesis posits that sensory systems of animals strive to encode sensory signals efficiently by taking into account the redundancies in them. This principle has been very successful in explaining response properties of visual sensory neurons as adaptations to the statistics of natural images. Recently, we have begun to extend the efficient coding hypothesis to active perception through a form of intrinsically motivated learning: a sensory model learns an efficient code for the sensory signals while a reinforcement learner generates movements of the sense organs to improve the encoding of the signals. To this end, it receives an intrinsically generated reinforcement signal indicating how well the sensory model encodes the data. This approach has been tested in the context of binocular vison, leading to the autonomous development of disparity tuning and vergence control. Here we systematically investigate the robustness of the new approach in the context of a binocular vision system implemented on a robot. Robustness is an important aspect that reflects the ability of the system to deal with unmodeled disturbances or events, such as insults to the system that displace the stereo cameras. To demonstrate the robustness of our method and its ability to self-calibrate, we introduce various perturbations and test if and how the system recovers from them. We find that (1) the system can fully recover from a perturbation that can be compensated through the system's motor degrees of freedom, (2) performance degrades gracefully if the system cannot use its motor degrees of freedom to compensate for the perturbation, and (3) recovery from a perturbation is improved if both the sensory encoding and the behavior policy can adapt to the perturbation. Overall, this work demonstrates that our intrinsically motivated learning approach for efficient coding in active perception gives rise to a self-calibrating perceptual system of high robustness. PMID:24223552

  11. An overview of instrumentation for the Large Binocular Telescope

    Science.gov (United States)

    Wagner, R. Mark

    2010-07-01

    An overview of instrumentation for the Large Binocular Telescope is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27 × 27) mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the straight-through F/15 Gregorian focus incorporating multiple slit masks for multi-object spectroscopy over a 6 field and spectral resolutions of up to 8000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCIFER), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at a bent interior focal station and designed for seeing-limited (FOV: 4 × 4) imaging, long-slit spectroscopy, and multi-object spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0.5 × 0.5) imaging and long-slit spectroscopy. Strategic instruments under development for the remaining two combined focal stations include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near-infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. The availability of all these instruments mounted simultaneously on the LBT permits unique science, flexible scheduling, and improved operational support. Over the past two years the LBC and the first LUCIFER instrument have been brought into routine scientific operation and MODS1 commissioning is set to begin in the fall of 2010.

  12. The role of binocular disparity in rapid scene and pattern recognition

    OpenAIRE

    Valsecchi, M.; Caziot, B.; Backus, B. T.; Gegenfurtner, K. R.

    2013-01-01

    We investigated the contribution of binocular disparity to the rapid recognition of scenes and simpler spatial patterns using a paradigm combining backward masked stimulus presentation and short-term match-to-sample recognition. First, we showed that binocular disparity did not contribute significantly to the recognition of briefly presented natural and artificial scenes, even when the availability of monocular cues was reduced. Subsequently, using dense random dot stereograms as stimuli, we ...

  13. Rapid plasticity of binocular connections in developing monkey visual cortex (V1)

    OpenAIRE

    Zhang, Bin; Bi, Hua; Sakai, Eiichi; Maruko, Ichiro; Zheng, Jianghe; Smith, Earl L.; Chino, Yuzo M.

    2005-01-01

    The basic sets of cortical connections are present at birth in the primate visual system. The maintenance and refinement of these innate connections are highly dependent on normal visual experience, and prolonged exposure to binocularly uncorrelated signals early in life severely disrupts the normal development of binocular functions. However, very little is known about how rapidly these changes in the functional organization of primate visual cortex emerge or what are the sequence and the na...

  14. Effect of Near Work on Binocular Vision Measurements in Adults with Convergence Insufficiency

    OpenAIRE

    Yi Pang, OD, PhD; Helen Gabriel, OD; Kelly A. Frantz, OD

    2015-01-01

    Background: Convergence insufficiency (CI) is a common binocular vision disorder. A common characteristic of CI is that patients have more symptoms, such as eyestrain and headache, after close work. The purpose of this study was to determine whether 30 minutes of reading affects the binocular and accommodative measurements used in the diagnosis of CI. Methods: Eighteen normal adult subjects and eighteen adult CI subjects (symptomatic and asymptomatic) were recruited. None of the CI subjec...

  15. The relationship between binocular vision symptoms and near point of convergence

    OpenAIRE

    Momeni-Moghaddam Hamed; A Goss David; Ehsani Marzieh

    2013-01-01

    Aim and Background: Due to the relatively high prevalence of binocular vision anomalies, a regular examination including tests for assessment and determination of these anomalies is necessary. The aim of this study was to assess the relationship between near point of convergence (NPC) and near binocular vision symptoms and finding of an NPC cutoff point for symptoms in university students. Materials and Methods: In this cross-sectional study, 124 students of different majors of Zahedan Univer...

  16. Problems with balance and binocular visual dysfunction are associated with post-stroke fatigue

    DEFF Research Database (Denmark)

    Schow, Trine; Teasdale, Thomas William; Jensen Quas, Kirsten;

    2016-01-01

    Trine Schow, Thomas William Teasdale, Kirsten Jensen Quas& Morten Arendt Rasmussen (2016): Problems with balance and binocular visual dysfunction are associated with post-stroke fatigue, Topics in Stroke Rehabilitation, DOI: 10.1080/10749357.2016.1188475......Trine Schow, Thomas William Teasdale, Kirsten Jensen Quas& Morten Arendt Rasmussen (2016): Problems with balance and binocular visual dysfunction are associated with post-stroke fatigue, Topics in Stroke Rehabilitation, DOI: 10.1080/10749357.2016.1188475...

  17. Individual differences in the temporal dynamics of binocular rivalry and stimulus rivalry

    OpenAIRE

    Patel, Vaama; Stuit, Sjoerd; Blake, Randolph

    2015-01-01

    Binocular rivalry and stimulus rivalry are two forms of perceptual instability that arise when the visual system is confronted with conflicting stimulus information. In the case of binocular rivalry, dissimilar monocular stimuli are presented to the two eyes for an extended period of time, whereas for stimulus rivalry the dissimilar monocular stimuli are exchanged rapidly and repetitively between the eyes during extended viewing. With both forms of rivalry, one experiences extended durations ...

  18. Bistable Percepts in the Brain: fMRI Contrasts Monocular Pattern Rivalry and Binocular Rivalry

    OpenAIRE

    Athena Buckthought; Samuel Jessula; Mendola, Janine D.

    2011-01-01

    The neural correlates of binocular rivalry have been actively debated in recent years, and are of considerable interest as they may shed light on mechanisms of conscious awareness. In a related phenomenon, monocular rivalry, a composite image is shown to both eyes. The subject experiences perceptual alternations in which the two stimulus components alternate in clarity or salience. The experience is similar to perceptual alternations in binocular rivalry, although the reduction in visibility ...

  19. Understanding attentional modulation of binocular rivalry: a framework based on biased competition

    OpenAIRE

    Kevin Conrad Dieter; Duje eTadin

    2011-01-01

    Starting from early scientific explorations of binocular rivalry, researchers have wondered about the degree to which an observer can exert voluntary attentional control over rivalry dynamics. The answer to this question would not only reveal the extent to which we may determine our own conscious visual experience, but also advance our understanding of the neural mechanisms underlying binocular rivalry. Classic studies, intriguingly, reached contradictory conclusions, ranging from an absence ...

  20. Retinotopic and non-retinotopic stimulus encoding in binocular rivalry and the involvement of feedback

    OpenAIRE

    van Boxtel, J.J.A.; Alais, D.; Ee, R

    2008-01-01

    Adaptation is one of the key constituents of the perceptual alternation process during binocular rivalry, as it has been shown that preadapting one of the rivaling pairs before rivalry onset biases perception away from the adapted stimulus during rivalry. We investigated the influence of retinotopic and spatiotopic preadaptation on binocular rivalry. We show that for grating stimuli, preadaptation only influences rivalry when adaptation and rivalry locations are retinotopically matched. With ...

  1. Individual Differences in Temporal Dynamics of Binocular Rivalry and of Stimulus Rivalry

    OpenAIRE

    Patel, Vaama; Stuit, Sjoerd; Blake, Randolph

    2015-01-01

    Binocular rivalry and stimulus rivalry are two forms of perceptual instability that arise when the visual system is confronted with conflicting stimulus information. In the case of binocular rivalry, dissimilar monocular stimuli are presented to the two eyes for an extended period of time, whereas for stimulus rivalry the dissimilar monocular stimuli are exchanged rapidly and repetitively between the eyes during extended viewing. With both forms of rivalry, one experiences extended durations ...

  2. Binocular Onset Rivalry at the Time of Saccades and Stimulus Jumps

    OpenAIRE

    Kalisvaart, Joke P.; Rampersad, Sumientra M.; Jeroen Goossens

    2011-01-01

    Recent studies suggest that binocular rivalry at stimulus onset, so called onset rivalry, differs from rivalry during sustained viewing. These observations raise the interesting question whether there is a relation between onset rivalry and rivalry in the presence of eye movements. We therefore studied binocular rivalry when stimuli jumped from one visual hemifield to the other, either through a saccade or through a passive stimulus displacement, and we compared rivalry after such displacemen...

  3. Congruent tactile stimulation reduces the strength of visual suppression during binocular rivalry

    OpenAIRE

    Claudia Lunghi; David Alais

    2015-01-01

    Presenting different images to each eye triggers ‘binocular rivalry’ in which one image is visible and the other suppressed, with the visible image alternating every second or so. We previously showed that binocular rivalry between cross-oriented gratings is altered when the fingertip explores a grooved stimulus aligned with one of the rivaling gratings: the matching visual grating's dominance duration was lengthened and its suppression duration shortened. In a more robust test, we here measu...

  4. Understanding Attentional Modulation of Binocular Rivalry: A Framework Based on Biased Competition

    OpenAIRE

    Dieter, Kevin Conrad; Tadin, Duje

    2011-01-01

    Starting from early scientific explorations of binocular rivalry, researchers have wondered about the degree to which an observer can exert voluntary attentional control over rivalry dynamics. The answer to this question would not only reveal the extent to which we may determine our own conscious visual experience, but also advance our understanding of the neural mechanisms underlying binocular rivalry. Classic studies, intriguingly, reached contradictory conclusions, ranging from an absence ...

  5. Temporal patterns of saccadic eye movements predict individual variation in alternation rate during binocular rivalry

    OpenAIRE

    Hancock, Sarah; Gareze, Lynn; Findlay, John M; Andrews, Timothy J.

    2012-01-01

    Interindividual variation has been shown in the rates at which subjects alternate in perception during viewing of binocular rivalry and other ambiguous figures. A similar pattern of interindividual variation is evident in the rate of eye movements. The aim of this study was to determine whether individual differences in the rate of binocular rivalry predict individual differences in the rate of eye movements. First, participants reported changes in perception during contour rivalry. We found ...

  6. Individual differences in the temporal dynamics of binocular rivalry and stimulus rivalry.

    Science.gov (United States)

    Patel, Vaama; Stuit, Sjoerd; Blake, Randolph

    2015-04-01

    Binocular rivalry and stimulus rivalry are two forms of perceptual instability that arise when the visual system is confronted with conflicting stimulus information. In the case of binocular rivalry, dissimilar monocular stimuli are presented to the two eyes for an extended period of time, whereas for stimulus rivalry the dissimilar monocular stimuli are exchanged rapidly and repetitively between the eyes during extended viewing. With both forms of rivalry, one experiences extended durations of exclusive perceptual dominance that fluctuate between the two stimuli. Whether these two forms of rivalry arise within different stages of visual processing has remained debatable. Using an individual-differences approach, we found that both stimulus rivalry and binocular rivalry exhibited same-shaped distributions of dominance durations among a sample of 30 observers and, moreover, that the dominance durations measured during binocular and stimulus rivalry were significantly correlated among our sample of observers. Furthermore, we found a significant, positive correlation between alternation rate in binocular rivalry and the incidence of stimulus rivalry. These results suggest that the two forms of rivalry may be tapping common neural mechanisms, or at least different mechanisms with comparable time constants. It remains to be learned just why the incidences of binocular rivalry and stimulus rivalry vary so greatly among people. PMID:25092387

  7. EXO-ZODI MODELING FOR THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Grant M.; Wyatt, Mark C.; Panić, Olja; Shannon, Andrew [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Bailey, Vanessa; Defrère, Denis; Hinz, Philip M.; Rieke, George H.; Skemer, Andrew J.; Su, Katherine Y. L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Bryden, Geoffrey; Mennesson, Bertrand; Morales, Farisa; Serabyn, Eugene [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Danchi, William C.; Roberge, Aki; Stapelfeldt, Karl R. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt, MD 20771 (United States); Haniff, Chris [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Lebreton, Jérémy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Millan-Gabet, Rafael [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); and others

    2015-02-01

    Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders of magnitude above the level of the solar system's zodiacal cloud, so characterization of the brightness distribution of exo-zodi down to much fainter levels is needed. To this end, the Large Binocular Telescope Interferometer (LBTI) will detect thermal emission from habitable zone exo-zodi a few times brighter than solar system levels. Here we present a modeling framework for interpreting LBTI observations, which yields dust levels from detections and upper limits that are then converted into predictions and upper limits for the scattered light surface brightness. We apply this model to the HOSTS survey sample of nearby stars; assuming a null depth uncertainty of 10{sup –4} the LBTI will be sensitive to dust a few times above the solar system level around Sun-like stars, and to even lower dust levels for more massive stars.

  8. A buyer's and user's guide to astronomical telescopes and binoculars

    CERN Document Server

    Mullaney, James

    2014-01-01

    Amateur astronomers of all skill levels are always contemplating their next telescope, and this book points the way to the most suitable instruments. Similarly, those who are buying their first telescopes – and these days not necessarily a low-cost one – will be able to compare and contrast different types and manufacturers. This revised new guide provides an extensive overview of binoculars and telescopes. It includes detailed up-to-date information on sources, selection and use of virtually every major type, brand, and model on today’s market, a truly invaluable treasure-trove of information and helpful advice for all amateur astronomers. Originally written in 2006, much of the first edition is inevitably now out of date, as equipment advances and manufacturers come and go. This second edition not only updates all the existing sections but adds two new ones: Astro-imaging and Professional-Amateur collaboration. Thanks to the rapid and amazing developments that have been made in digital cameras it is...

  9. Action imitation changes perceptual alternations in binocular rivalry.

    Directory of Open Access Journals (Sweden)

    Enrico Di Pace

    Full Text Available Binocular rivalry is a visual phenomenon in which perception alternates between two different monocular images presented to each of the two eyes. Here, we propose using this phenomenon as a method to study the relation between action execution and action perception. In our experiment, a simple background (a checkerboard was contrasted with a video representing a hand continuously grasping and releasing a ball. In Experiment 1, our subjects were asked to reproduce the perceived movement with their right hand whenever they became aware of it and to stop doing this when the checkerboard dominated. Our results revealed that motor imitation of the perceived action significantly increased the time spent perceiving the hand. Three control experiments showed that these effects were not due to a generic involvement of focused attention (Experiment 2 and 3, to a verbal description of the performed action (Experiment 3 or to the execution of an unrelated movement of the hand (Experiment 4. Although an intrinsic connection between action execution and attention cannot be excluded with certainty, and the boundary between action imitation and unrelated action execution may vary along various degrees of similarity, on the whole, the present results seem to suggest, at least on a preliminary basis, that action imitation do play a relevant role in the perception of action. We discuss these findings in the frame of current theories concerning the relation between perception and action.

  10. EXO-ZODI MODELING FOR THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    International Nuclear Information System (INIS)

    Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders of magnitude above the level of the solar system's zodiacal cloud, so characterization of the brightness distribution of exo-zodi down to much fainter levels is needed. To this end, the Large Binocular Telescope Interferometer (LBTI) will detect thermal emission from habitable zone exo-zodi a few times brighter than solar system levels. Here we present a modeling framework for interpreting LBTI observations, which yields dust levels from detections and upper limits that are then converted into predictions and upper limits for the scattered light surface brightness. We apply this model to the HOSTS survey sample of nearby stars; assuming a null depth uncertainty of 10–4 the LBTI will be sensitive to dust a few times above the solar system level around Sun-like stars, and to even lower dust levels for more massive stars

  11. Sinusoidal calibration technique for Large Binocular Telescope system

    Science.gov (United States)

    Pieralli, F.; Puglisi, A.; Quiros Pacheco, F.; Esposito, S.

    2008-07-01

    Telescopes of 8 meter class, like Large Binocular Telescope (LBT), are based on the concept of Deformable Secondary Mirror (DSM); in order to calculate the best DSM shape that correct the measured aberrations we need to calibrate the AO system, so we need a correlation between the DSM and the wave front sensor (WFS), i.e. we need the Interaction Matrix (IM). Usually we obtain the IM in laboratory or at the telescope using as source a reference fiber that illuminates both the deformable mirror and wave front sensor. But in case of LBT and all large telescopes, this technique can be very difficult or sometimes impossible, and calibration may be required to be performed on sky. So we need new calibration techniques, and we investigate about sinusoidal modulation one for LBT case. In the Arcetri solar tower (inside Arcetri Observatory) we recreated a set up environment similar to the telescope, and thanks to that we can test the calibration system in the same condition of the LBT. In preparation for the test some simulations of this sinusoidal modulation technique were needed, in order to choose the best parameters that increased SNR and reduced integration time. The paper will detail the simulation results of the calibration LBT system made with this new technique, and these results will be used to drive our tests in the tower.

  12. [Binocular photometer for measuring light perception in diseases of the visual pathway].

    Science.gov (United States)

    Stave, J; Guthoff, R

    1995-04-01

    In patients with a reduction in visual function because of optic nerve neuritis, light sensitivity is tested to detect differences between the right and left eye in combination with the swinging flashlight test and visual evoked potential (VEP). A binocular Zeiss microscope was modified to use integrated photometer-controlled binocular stimulus fields and a central light system for fixation and variation of the contrast (background illumination). For exact binocular measurements of light sensitivity on both eyes, electronically controlled test fields (visual angle 5 degrees-20 degrees) guarantees only macular or overfoveolar stimulation. In addition, splitting the light for each stimulus field from only one halogen lamp guarantees wave-length-independent testing. Patients with various retinal diseases and neuritis nervi optici pathology were examined using pattern VEP, testing of the absolute lower threshold of light sensitivity, and binocular comparison over the range of luminous density. This binocular optical photometer system allowed minimal differences to be identified in the present visual function and after the eye had recovered from optic nerve neuritis. PMID:7780279

  13. The research on binocular stereo video imaging and display system based on low-light CMOS

    Science.gov (United States)

    Xie, Ruobing; Li, Li; Jin, Weiqi; Guo, Hong

    2015-10-01

    It is prevalent for the low-light night-vision helmet to equip the binocular viewer with image intensifiers. Such equipment can not only acquire night vision ability, but also obtain the sense of stereo vision to achieve better perception and understanding of the visual field. However, since the image intensifier is for direct-observation, it is difficult to apply the modern image processing technology. As a result, developing digital video technology in night vision is of great significance. In this paper, we design a low-light night-vision helmet with digital imaging device. It consists of three parts: a set of two low-illumination CMOS cameras, a binocular OLED micro display and an image processing PCB. Stereopsis is achieved through the binocular OLED micro display. We choose Speed-Up Robust Feature (SURF) algorithm for image registration. Based on the image matching information and the cameras' calibration parameters, disparity can be calculated in real-time. We then elaborately derive the constraints of binocular stereo display. The sense of stereo vision can be obtained by dynamically adjusting the content of the binocular OLED micro display. There is sufficient space for function extensions in our system. The performance of this low-light night-vision helmet can be further enhanced in combination with The HDR technology and image fusion technology, etc.

  14. Binocular Visual Navigation and Obstacle Avoidance of Mobile Robots Based on Speeded-Up Robust Features

    Institute of Scientific and Technical Information of China (English)

    WANG Meng-di; HAN Bao-ling; LUO Qing-sheng

    2013-01-01

    This article presents a good robust and real-time system scheme of the mobile robot obstacle detection and navigation, which principle of work is based on the feature descriptor SURF. In this scheme, firstly, the image information of the mobile robot path was captured by the binocular camera; then the feature points were extracted and corresponding matched using SURF to the binocular images as the undetected obstacles;finally fixed the position of the objective by the parallax between the matching points combining with the binocular vision calibration model. Theoretical derivation and experimental results show that this scheme is more accurate for the detection and navigation of the interest points. It has fast matching speed and high accuracy and low error. So, it has certain practical effect and popularizing value for the mobile robot real-time obstacle avoidance and navigation.

  15. Binocular fusion in Panum's limiting case of stereopsis obeys the uniqueness constraint

    Institute of Scientific and Technical Information of China (English)

    WANG; Zhihong; (王志宏); WU; Xinnian; (吴新年); NI; Rui; (倪睿); WANG; Yunjiu; (汪云九)

    2001-01-01

    In the information processing procedure of stereo vision, the uniqueness constraint has been used as one of the constraints to solve the "correspondence problem". While the uniqueness constraint is valid in most cases, whether it is still valid in some particular stimulus configuration (such as Panum's limiting case) has been a problem of widespread debate for a long time. To investigate the problem, we adopted the Panum's limiting case as its basic stimulus configuration, and delved into the phenomenon of binocular fusion from two distinct aspects: visual direction and orientation disparity. The results show that in Panum's limiting case binocular fusion does not comply with the rules governing regular binocular fusion as far as visual direction and orientation disparity are concerned. This indicates that double fusion does not happen in Panum's limiting case and that the uniqueness constraint is still valid.

  16. Binocular fusion in Panum's limiting case of stereopsisobeys the uniqueness constraint

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the information processing procedure of stereo vision, theuniqueness constraint has been used as one of the constraints to solve the "correspondence problem". While the uniqueness constraint is valid in most cases, whether it is still valid in some particular stimulus configuration (such as Panum's limiting case) has been a problem of widespread debate for a long time. To investigate the problem, we adopted the Panum's limiting case as its basic stimulus configuration, and delved into the phenomenon of binocular fusion from two distinct aspects: visual direction and orientation disparity. The results show that in Panum's limiting case binocular fusion does not comply with the rules governing regular binocular fusion as far as visual direction and orientation disparity are concerned. This indicates that double fusion does not happen in Panum's limiting case and that the uniqueness constraint is still valid.

  17. No-reference stereoscopic image quality measurement based on generalized local ternary patterns of binocular energy response

    Science.gov (United States)

    Zhou, Wujie; Yu, Lu

    2015-09-01

    Perceptual no-reference (NR) quality measurement of stereoscopic images has become a challenging issue in three-dimensional (3D) imaging fields. In this article, we propose an efficient binocular quality-aware features extraction scheme, namely generalized local ternary patterns (GLTP) of binocular energy response, for general-purpose NR stereoscopic image quality measurement (SIQM). More specifically, we first construct the binocular energy response of a distorted stereoscopic image with different stimuli of amplitude and phase shifts. Then, the binocular quality-aware features are generated from the GLTP of the binocular energy response. Finally, these features are mapped to the subjective quality score of the distorted stereoscopic image by using support vector regression. Experiments on two publicly available 3D databases confirm the effectiveness of the proposed metric compared with the state-of-the-art full reference and NR metrics.

  18. Effect of cover adjustment on binocular vision function in children with anisometropic amblyopia

    OpenAIRE

    Kai Zhu

    2016-01-01

    AIM:To explore and study the effect of cover adjustment on binocular visual function in children with anisometropic amblyopia.METHODS: Forty-five children with anisometropic amblyopia of our hospital from July 2014 to April 2015 were as the study group, and treated by cover adjustment. Then 40 cases of healthy volunteers were selected as the blank control group. The binocular visual function of the subjects was observed.RESULTS: Before treatments, at 1 and 3mo after treatments, the positive r...

  19. Development of monocular and binocular multi-focus 3D display systems using LEDs

    Science.gov (United States)

    Kim, Sung-Kyu; Kim, Dong-Wook; Son, Jung-Young; Kwon, Yong-Moo

    2008-04-01

    Multi-focus 3D display systems are developed and a possibility about satisfaction of eye accommodation is tested. The multi-focus means the ability of monocular depth cue to various depth levels. By achieving the multi-focus function, we developed 3D display systems for one eye and both eyes, which can satisfy accommodation to displayed virtual objects within defined depth. The monocular accommodation and the binocular convergence 3D effect of the system are tested and a proof of the satisfaction of the accommodation and experimental result of the binocular 3D fusion are given as results by using the proposed 3D display systems.

  20. Experimental platform for moving double-camera system based on binocular vergence eye movements

    Institute of Scientific and Technical Information of China (English)

    LI Heng-yu; LUO Jun; XIE Shao-rong; LI Lei; LI Qing-mei

    2009-01-01

    A control model of binocular vergence eye movements is presented. The control model can reduce blind areas caused by the double cameras in motion platform. In order to validate the model performance, an experimental platform and its control system based on TMS320LF2407 are designed. The control system has its compacted configuration and high reliability. The simulation and experimental results show that the control system can realize binocular vergence movements. Compared with the conventional moving double cameras system, this new system can considerably reduce blind areas.

  1. A binocular pupil model for simulation of relative afferent pupil defect, RAPD.

    Science.gov (United States)

    Privitera, Claudio M; Stark, Lawrence W

    2004-01-01

    The human pupil is an important element studied in many clinical procedures. The binocular pupil model presented has a topology encompassing much of the complexity of the pupil system neurophysiology. The dynamic parameters of the model were matched against pupil experiments under multiple conditions. It simulates responses to the swinging flashlight test for different degrees of relative afferent pupil defects, RAPD. PMID:17271776

  2. Binocular self-calibration performed via adaptive genetic algorithm based on laser line imaging

    Science.gov (United States)

    Apolinar Muñoz Rodríguez, J.; Mejía Alanís, Francisco Carlos

    2016-07-01

    An accurate technique to perform binocular self-calibration by means of an adaptive genetic algorithm based on a laser line is presented. In this calibration, the genetic algorithm computes the vision parameters through simulated binary crossover (SBX). To carry it out, the genetic algorithm constructs an objective function from the binocular geometry of the laser line projection. Then, the SBX minimizes the objective function via chromosomes recombination. In this algorithm, the adaptive procedure determines the search space via line position to obtain the minimum convergence. Thus, the chromosomes of vision parameters provide the minimization. The approach of the proposed adaptive genetic algorithm is to calibrate and recalibrate the binocular setup without references and physical measurements. This procedure leads to improve the traditional genetic algorithms, which calibrate the vision parameters by means of references and an unknown search space. It is because the proposed adaptive algorithm avoids errors produced by the missing of references. Additionally, the three-dimensional vision is carried out based on the laser line position and vision parameters. The contribution of the proposed algorithm is corroborated by an evaluation of accuracy of binocular calibration, which is performed via traditional genetic algorithms.

  3. The Effects of Sports Vision Training on Binocular Vision Function in Female University Athletes

    Science.gov (United States)

    Zwierko, Teresa; Puchalska-Niedbał, Lidia; Krzepota, Justyna; Markiewicz, Mikołaj; Woźniak, Jarosław; Lubiński, Wojciech

    2015-01-01

    Binocular vision is the most important visual cue for spatial orientation in many sports. In this study, we investigated how binocular vision was influenced by an eye training program that may be used to improve individual's oculomotor function. The experiment involved twenty-four female student athletes from team ball sports (soccer, basketball, handball). After an initial testing session, 12 participants were randomly allocated to the experimental group. Optometric investigation which included synoptophore testing and a test of dissociated horizontal phoria based on the Maddox method was performed three times: before the experiment, after eight weeks of eye training (3 times a week for 20 minutes), and four weeks after the experiment was terminated. Eye exercise methodology was based on orthoptic, sport and psychological aspects of performance. The phoria screening examination showed that exophoria was the most frequent disorder of binocular vision. Low fusional vergence range was also observed. Following the training period, 3 of the 6 oculomotor variables improved. The greatest effect was observed in near dissociated phoria (χ2 =14.56, p=0.001 for the right eye; χ2 =14.757, p=0.001 for the left eye) and fusional convergence (χ2 =8.522, p=0.014). The results of the retention test conducted four weeks after the experiment confirmed the effectiveness of the vision training program. The results of the study suggest that binocular functions are trainable and can be improved by means of appropriate visual training. PMID:26925183

  4. Binocular Vision Problems in Refractive Surgery Patients: Vision Therapy Case Reports

    Directory of Open Access Journals (Sweden)

    Gina Day, OD

    2015-02-01

    Full Text Available Background: Some post-LASIK patients complain of blurry distance vision months after refractive surgery, despite good corneal healing and negligible refractive error. We postulated that perceiving blur in the absence of refractive error or significant monocular aberrations might result from poor binocular control. Binocular vision testing in a series of such patients revealed convergence problems in 83% of cases. Case Reports: We report on 8 patients (average age 37.4 yrs who completed up to 40 sessions of vision therapy (VT, either completely via computer or in a combination of computer orthoptics and office vision therapy. Seven patients had received LASIK; one had PRK. Optometric measurements and symptoms were recorded before and after VT treatment, starting at least 3 months after refractive surgery. Near point of convergence improved in 7 cases following VT, and convergence break and/or recovery improved in 6 cases. Six cases reported symptom reduction, and pre-presbyopic cases tended to improve accommodative facility. The number of binocular functions showing improvement per case correlated with the number of VT sessions completed. Convergence changes were statistically significant when pre-/post-VT data were compared for these cases as a group. Conclusion: Patients complaining of distance blur following refractive surgery may have undiagnosed binocular vision problems. VT incorporating an internet orthoptics component improved convergence ability in the cases reported here, and most patients reported symptomatic relief.

  5. Graphical and Normative Analysis of Binocular Vision by Mini Computer: A Teaching Aid and Clinical Tool.

    Science.gov (United States)

    Kees, Martin; Schor, Clifton

    1981-01-01

    An inexpensive computer graphics systems (Commodore PET), used as a video aid for teaching students advanced case analysis, is described. The course provides students with the analytical tools for evaluating with graphical and statistical techniques and treating with lenses, prisms, and orthoptics various anomalies of binocular vision. (MLW)

  6. The Effects of Sports Vision Training on Binocular Vision Function in Female University Athletes.

    Science.gov (United States)

    Zwierko, Teresa; Puchalska-Niedbał, Lidia; Krzepota, Justyna; Markiewicz, Mikołaj; Woźniak, Jarosław; Lubiński, Wojciech

    2015-12-22

    Binocular vision is the most important visual cue for spatial orientation in many sports. In this study, we investigated how binocular vision was influenced by an eye training program that may be used to improve individual's oculomotor function. The experiment involved twenty-four female student athletes from team ball sports (soccer, basketball, handball). After an initial testing session, 12 participants were randomly allocated to the experimental group. Optometric investigation which included synoptophore testing and a test of dissociated horizontal phoria based on the Maddox method was performed three times: before the experiment, after eight weeks of eye training (3 times a week for 20 minutes), and four weeks after the experiment was terminated. Eye exercise methodology was based on orthoptic, sport and psychological aspects of performance. The phoria screening examination showed that exophoria was the most frequent disorder of binocular vision. Low fusional vergence range was also observed. Following the training period, 3 of the 6 oculomotor variables improved. The greatest effect was observed in near dissociated phoria (χ(2) =14.56, p=0.001 for the right eye; χ(2) =14.757, p=0.001 for the left eye) and fusional convergence (χ(2) =8.522, p=0.014). The results of the retention test conducted four weeks after the experiment confirmed the effectiveness of the vision training program. The results of the study suggest that binocular functions are trainable and can be improved by means of appropriate visual training. PMID:26925183

  7. Travelling waves of activity in primary visual cortex during binocular rivalry

    OpenAIRE

    Lee, Sang-Hun; Blake, Randolph; Heeger, David J.

    2004-01-01

    When the two eyes view large dissimilar patterns that induce binocular rivalry, alternating waves of visibility are experienced, as one pattern sweeps the other out of conscious awareness. Here we show tight linkage between dynamics of perceptual waves during rivalry and neural events in human primary visual cortex (V1).

  8. The Influence of Anxiety on the Initial Selection of Emotional Faces Presented in Binocular Rivalry

    Science.gov (United States)

    Gray, Katie L. H.; Adams, Wendy J.; Garner, Matthew

    2009-01-01

    Neurocognitive theories of anxiety predict that threat-related information can be evaluated before attentional selection, and can influence behaviour differentially in high anxious compared to low anxious individuals. We investigate this further by presenting emotional and neutral faces in an adapted binocular rivalry paradigm. We show that the…

  9. The impact of stimulus complexity and frequency swapping on stabilization of binocular rivalry

    DEFF Research Database (Denmark)

    Sandberg, Kristian; Bahrami, Bahador; Lindeløv, Jonas Kristoffer;

    2011-01-01

    Binocular rivalry occurs when an image is presented to one eye while at the same time another, incongruent, image is presented to the other eye in the corresponding retinotopic location and conscious perception alternates spontaneously between the two monocular views. If a short blank period is...

  10. Touch interacts with vision during binocular rivalry with a tight orientation tuning.

    Directory of Open Access Journals (Sweden)

    Claudia Lunghi

    Full Text Available Multisensory integration is a common feature of the mammalian brain that allows it to deal more efficiently with the ambiguity of sensory input by combining complementary signals from several sensory sources. Growing evidence suggests that multisensory interactions can occur as early as primary sensory cortices. Here we present incompatible visual signals (orthogonal gratings to each eye to create visual competition between monocular inputs in primary visual cortex where binocular combination would normally take place. The incompatibility prevents binocular fusion and triggers an ambiguous perceptual response in which the two images are perceived one at a time in an irregular alternation. One key function of multisensory integration is to minimize perceptual ambiguity by exploiting cross-sensory congruence. We show that a haptic signal matching one of the visual alternatives helps disambiguate visual perception during binocular rivalry by both prolonging the dominance period of the congruent visual stimulus and by shortening its suppression period. Importantly, this interaction is strictly tuned for orientation, with a mismatch as small as 7.5° between visual and haptic orientations sufficient to annul the interaction. These results indicate important conclusions: first, that vision and touch interact at early levels of visual processing where interocular conflicts are first detected and orientation tunings are narrow, and second, that haptic input can influence visual signals outside of visual awareness, bringing a stimulus made invisible by binocular rivalry suppression back to awareness sooner than would occur without congruent haptic input.

  11. Retinotopic and non-retinotopic stimulus encoding in binocular rivalry and the involvement of feedback

    NARCIS (Netherlands)

    van Boxtel, J.J.A.; Alais, D.; van Ee, R.

    2008-01-01

    Adaptation is one of the key constituents of the perceptual alternation process during binocular rivalry, as it has been shown that preadapting one of the rivaling pairs before rivalry onset biases perception away from the adapted stimulus during rivalry. We investigated the influence of retinotopic

  12. Removal of monocular interactions equates rivalry behavior for monocular, binocular, and stimulus rivalries

    NARCIS (Netherlands)

    van Boxtel, J.J.A.; Knapen, T.H.J.; Erkelens, C.J.; van Ee, R.

    2008-01-01

    When the two eyes are presented with conflicting stimuli, perception starts to fluctuate over time (i.e., binocular rivalry). A similar fluctuation occurs when two patterns are presented to a single eye (i.e., monocular rivalry), or when they are swapped rapidly and repeatedly between the eyes (i.e.

  13. Binocular onset rivalry at the time of saccades and stimulus jumps.

    NARCIS (Netherlands)

    Kalisvaart, J.P.; Rampersad, S.M.; Goossens, H.H.L.M.

    2011-01-01

    Recent studies suggest that binocular rivalry at stimulus onset, so called onset rivalry, differs from rivalry during sustained viewing. These observations raise the interesting question whether there is a relation between onset rivalry and rivalry in the presence of eye movements. We therefore stud

  14. Neurons that detect interocular conflict during binocular rivalry revealed with EEG.

    Science.gov (United States)

    Katyal, Sucharit; Engel, Stephen A; He, Bin; He, Sheng

    2016-01-01

    When the two eyes view incompatible images, perception alternates between them. What neural computations underlie this binocular rivalry? Perceptual alternations may simply reflect competition between the sets of monocular neurons that respond to each image, with the stronger driving perception. Here, we test an alternative hypothesis, that the computations that resolve rivalry make use of an active signal that reflects interocular conflict. Images presented to each eye were flickered at different frequencies while we measured steady-state visually evoked potentials (SSVEP). Signals at frequencies that are combinations of the two input frequencies can arise only from binocular neurons. In a first experiment, we measured energy at these "intermodulation" frequencies during binocular rivalry and found it to be highest immediately before rivalry restarted following a period of incomplete resolution of rivalry (a "mixed" percept). This suggests that the intermodulation signals may arise from neurons important for resolving the conflict between the two eyes' inputs. In a second experiment, we tested whether the intermodulation signal arose from neurons that measure interocular conflict by parametrically increasing conflict while simultaneously reducing image contrast. The activity of neurons that receive input from both eyes but are not sensitive to conflict should reduce monotonically as contrast decreases. The intermodulation response, however, peaked at intermediate levels of conflict, suggesting that it arises in part from neurons that respond to interocular conflict. Binocular rivalry appears to depend on an active mechanism that detects interocular conflict, whose levels of activity can be measured by the intermodulation frequencies of the SSVEP. PMID:26891825

  15. Cataract surgery: emotional reactions of patients with monocular versus binocular vision Cirurgia de catarata: aspectos emocionais de pacientes com visão monocular versus binocular

    Directory of Open Access Journals (Sweden)

    Roberta Ferrari Marback

    2012-12-01

    Full Text Available PURPOSE: To analyze emotional reactions related to cataract surgery in two groups of patients (monocular vision - Group 1; binocular vision - Group 2. METHODS: A transversal comparative study was performed using a structured questionnaire from a previous exploratory study before cataract surgery. RESULTS: 206 patients were enrolled in the study, 96 individuals in Group 1 (69.3 ± 10.4 years and 110 in Group 2 (68.2 ± 10.2 years. Most patients in group 1 (40.6% and 22.7% of group 2, reported fear of surgery (pOBJETIVO: Verificar reações emocionais relacionadas à cirurgia de catarata entre pacientes com visão monocular (Grupo 1 e binocular (Grupo 2. MÉTODOS: Foi realizado um estudo tranversal, comparativo por meio de um questionário estruturado respondido por pacientes antes da cirurgia de catarata. RESULTADOS: A amostra foi composta de 96 pacientes no Grupo 1 (69.3 ± 10.4 anos e 110 no Grupo 2 (68.2 ± 10.2 anos. Consideravam apresentar medo da cirugia 40.6% do Grupo 1 e 22.7% do Grupo 2 (p<0.001 e entre as principais causas do medo, a possibilidade de perda da visão, complicações cirúrgicas e a morte durante o procedimento foram apontadas. Os sentimentos mais comuns entre os dois grupos foram dúvidas a cerca dos resultados da cirurgia e o nervosismo diante do procedimento. CONCLUSÃO: Pacientes com visão monocular apresentaram mais medo e dúvidas relacionadas à cirurgia de catarata comparados com aqueles com visão binocular. Portanto, é necessário que os médicos considerem estas reações emocionais e invistam mais tempo para esclarecer os riscos e benefícios da cirurgia de catarata.

  16. Binocular eyelid closure promotes anatomical but not behavioral recovery from monocular deprivation.

    Science.gov (United States)

    Duffy, Kevin R; Bukhamseen, Dalia H; Smithen, Matthew J; Mitchell, Donald E

    2015-09-01

    Deprivation of patterned vision of frontal eyed mammals early in postnatal life alters structural and functional attributes of neurones in the central visual pathways, and can produce severe impairments of the vision of the deprived eye that resemble the visual loss observed in human amblyopia. A traditional approach to treatment of amblyopia has been the occlusion of the stronger fellow eye in order to force use of the weaker eye and thereby strengthen its connections in the visual cortex. Although this monocular treatment strategy can be effective at promoting recovery of visual acuity of the amblyopic eye, such binocular visual functions as stereoscopic vision often remain impaired due in part to the lack of concordant vision during the period of unilateral occlusion. The recent development of binocular approaches for treatment of amblyopia that improve the possibility for binocular interaction have achieved success in promoting visual recovery. The full and rapid recovery of visual acuity observed in amblyopic kittens placed in complete darkness is an example of a binocular treatment whose success may in part derive from a restored balance of visually-driven neural activity. In the current study we examined as an alternative to dark rearing the efficacy of binocular lid suture (BLS) to stimulate anatomical and visual recovery from a preceding amblyogenic period of monocular deprivation. In the dorsal lateral geniculate nucleus (dLGN) of monocularly deprived kittens, darkness or BLS for 10days produced a complete recovery of neurone soma size within initially deprived layers. The growth of neurone somata within initially deprived dLGN layers after darkness or BLS was accompanied by an increase in neurotrophin-4/5 labeling within these layers. Although anatomical recovery was observed in both recovery conditions, BLS failed to promote any improvement of the visual acuity of the deprived eye no matter whether it followed immediately or was delayed with respect to

  17. Is there any evidence for the validity of diagnostic criteria used for accommodative and nonstrabismic binocular dysfunctions?

    OpenAIRE

    Cacho Martínez, Pilar; García Muñoz, Ángel; Ruiz Cantero, María Teresa

    2014-01-01

    Purpose: To analyze the diagnostic criteria used in the scientific literature published in the past 25 years for accommodative and nonstrabismic binocular dysfunctions and to explore if the epidemiological analysis of diagnostic validity has been used to propose which clinical criteria should be used for diagnostic purposes. Methods: We carried out a systematic review of papers on accommodative and non-strabic binocular disorders published from 1986 to 2012 analysing the MEDLINE, CINAHL, Psyc...

  18. Underwater binocular imaging of aerial objects versus the position of eyes relative to the flat water surface.

    Science.gov (United States)

    Barta, András; Horváth, Gábor

    2003-12-01

    The apparent position, size, and shape of aerial objects viewed binocularly from water change as a result of the refraction of light at the water surface. Earlier studies of the refraction-distorted structure of the aerial binocular visual field of underwater observers were restricted to either vertically or horizontally oriented eyes. Here we calculate the position of the binocular image point of an aerial object point viewed by two arbitrarily positioned underwater eyes when the water surface is flat. Assuming that binocular image fusion is performed by appropriate vergent eye movements to bring the object's image onto the foveae, the structure of the aerial binocular visual field is computed and visualized as a function of the relative positions of the eyes. We also analyze two erroneous representations of the underwater imaging of aerial objects that have occurred in the literature. It is demonstrated that the structure of the aerial binocular visual field of underwater observers distorted by refraction is more complex than has been thought previously. PMID:14686517

  19. Looking into the water with oblique head tilting: revision of the aerial binocular imaging of underwater objects.

    Science.gov (United States)

    Horváth, Gábor; Buchta, Krisztián; Varjú, Dezsö

    2003-06-01

    It is a well-known phenomenon that when we look into the water with two aerial eyes, both the apparent position and the apparent shape of underwater objects are different from the real ones because of refraction at the water surface. Earlier studies of the refraction-distorted structure of the underwater binocular visual field of aerial observers were restricted to either vertically or horizontally oriented eyes. We investigate a generalized version of this problem: We calculate the position of the binocular image point of an underwater object point viewed by two arbitrarily positioned aerial eyes, including oblique orientations of the eyes relative to the flat water surface. Assuming that binocular image fusion is performed by appropriate vergent eye movements to bring the object's image onto the foveas, the structure of the underwater binocular visual field is computed and visualized in different ways as a function of the relative positions of the eyes. We show that a revision of certain earlier treatments of the aerial imaging of underwater objects is necessary. We analyze and correct some widespread erroneous or incomplete representations of this classical geometric optical problem that occur in different textbooks. Improving the theory of aerial binocular imaging of underwater objects, we demonstrate that the structure of the underwater binocular visual field of aerial observers distorted by refraction is more complex than has been thought previously. PMID:12801180

  20. Perceptual "blankout" of monocular homogeneous fields (Ganzfelder) is prevented with binocular viewing.

    Science.gov (United States)

    Bolanowski, S J; Doty, R W

    1987-01-01

    The loss of visual perception or "blankout" which occurs when a homogeneous field (Ganzfeld) is presented monocularly is prevented when the same field is viewed binocularly. Thus, blankout cannot be retinal; and contours or transients in time and space are unnecessary for the continuous maintenance of visual perception. Experiments are reported in which blankout ensues only if the two eyes receive luminance disparities ca 0.75 log I. Furthermore, blankout is only marginally affected by stimulus intensity, nor is it dependent on stimulus hue. However, equally luminant but disparate hues presented to the two eyes produce perceptions reminiscent of blankout, with the darkness of blankout replaced with that of color. It is hypothesized that the underlying mechanisms have a commonality in the phenomena of blankout and binocular rivalry but several noncongruent features require explanation. PMID:3660657

  1. A low-dimensional model of binocular rivalry using winnerless competition

    Science.gov (United States)

    Ashwin, Peter; Lavric, Aureliu

    2010-05-01

    We discuss a novel minimal model for binocular rivalry (and more generally perceptual dominance) effects. The model has only three state variables, but nonetheless exhibits a wide range of input and noise-dependent switching. The model has two reciprocally inhibiting input variables that represent perceptual processes active during the recognition of one of the two possible states and a third variable that represents the perceived output. Sensory inputs only affect the input variables. We observe, for rivalry-inducing inputs, the appearance of winnerless competition in the perceptual system. This gives rise to a behaviour that conforms to well-known principles describing binocular rivalry (the Levelt propositions, in particular proposition IV: monotonic response of residence time as a function of image contrast) down to very low levels of stimulus intensity.

  2. VLSI design of 3D display processing chip for binocular stereo displays

    Institute of Scientific and Technical Information of China (English)

    Ge Chenyang; Zheng Nanning

    2010-01-01

    In order to develop the core chip supporting binocular stereo displays for head mounted display(HMD)and glasses-TV,a very large scale integrated(VLSI)design scheme is proposed by using a pipeline architecture for 3D display processing chip(HMD100).Some key techniques including stereo display processing and high precision video scaling based bicubic interpolation,and their hardware implementations which improve the image quality are presented.The proposed HMD100 chip is verified by the field-programmable gate array(FPGA).As one of innovative and high integration SoC chips,HMD100 is designed by a digital and analog mixed circuit.It can support binocular stereo display,has better scaling effect and integration.Hence it is applicable in virtual reality(VR),3D games and other microdisplay domains.

  3. Evaluation of Binocular Eye Trackers and Algorithms for 3D Gaze Interaction in Virtual Reality Environments

    Directory of Open Access Journals (Sweden)

    Thies Pfeiffer

    2009-03-01

    Full Text Available Tracking user's visual attention is a fundamental aspect in novel human-computer interaction paradigms found in Virtual Reality. For example, multimodal interfaces or dialogue-based communications with virtual and real agents greatly benefit from the analysis of the user's visual attention as a vital source for deictic references or turn-taking signals. Current approaches to determine visual attention rely primarily on monocular eye trackers. Hence they are restricted to the interpretation of two-dimensional fixations relative to a defined area of projection.The study presented in this article compares precision, accuracy and application performance of two binocular eye tracking devices. Two algorithms are compared which derive depth information as required for visual attention-based 3D interfaces. This information is further applied to an improved VR selection task in which a binocular eye tracker and an adaptive neural network algorithm is used during the disambiguation of partly occluded objects.

  4. On the contribution of binocular disparity to the long-term memory for natural scenes.

    Directory of Open Access Journals (Sweden)

    Matteo Valsecchi

    Full Text Available Binocular disparity is a fundamental dimension defining the input we receive from the visual world, along with luminance and chromaticity. In a memory task involving images of natural scenes we investigate whether binocular disparity enhances long-term visual memory. We found that forest images studied in the presence of disparity for relatively long times (7s were remembered better as compared to 2D presentation. This enhancement was not evident for other categories of pictures, such as images containing cars and houses, which are mostly identified by the presence of distinctive artifacts rather than by their spatial layout. Evidence from a further experiment indicates that observers do not retain a trace of stereo presentation in long-term memory.

  5. Research on Extraction of Bottom of Shoe Pattern Based on Binocular Stereo Vision

    Institute of Scientific and Technical Information of China (English)

    MA Xin-wu; GAN Yi; SUN Fu-jia

    2016-01-01

    In order to quickly and efficiently get the information of the bottom of the shoe pattern and spraying trajectory, the paper proposes a method based on binocular stereo vision .After acquiring target image , edge detection based on the canny algorithm , the paper begins stereo matching based on area and characteristics of algorithm.To eliminate false matching points , the paper uses the principle of polar geometry in computer vision . For the purpose of gaining the 3D point cloud of spraying curve , the paper adopts the principle of binocular stereo vision 3D measurement , and then carries on cubic spline curve fitting .By HALCON image processing software programming , it proves the feasibility and effectiveness of the method .

  6. Camera calibration method of binocular stereo vision based on OpenCV

    Science.gov (United States)

    Zhong, Wanzhen; Dong, Xiaona

    2015-10-01

    Camera calibration, an important part of the binocular stereo vision research, is the essential foundation of 3D reconstruction of the spatial object. In this paper, the camera calibration method based on OpenCV (open source computer vision library) is submitted to make the process better as a result of obtaining higher precision and efficiency. First, the camera model in OpenCV and an algorithm of camera calibration are presented, especially considering the influence of camera lens radial distortion and decentering distortion. Then, camera calibration procedure is designed to compute those parameters of camera and calculate calibration errors. High-accurate profile extraction algorithm and a checkboard with 48 corners have also been used in this part. Finally, results of calibration program are presented, demonstrating the high efficiency and accuracy of the proposed approach. The results can reach the requirement of robot binocular stereo vision.

  7. Acceptance of different multifocal contact lenses depending on the binocular findings.

    Science.gov (United States)

    Cagnolati, W

    1993-04-01

    In a clinical study the subjective acceptance as well as the quality of different visual functions was examined during the wearing of three multifocal lenses (Ciba Spectrum Bifocal, Allergan Echelon, and Essilor Variations). Ten subjects wore each of the 3 contact lens types for a period of 12 to 21 days after the binocular finding (bicentral or disparate vision within the Panum's area); further functions such as contrast or scotopic vision were qualified and/or quantified in a basic examination. All subjects (N = 5) with the binocular finding orthophoria/motorcompensated heterophoria preferred the Ciba Spectrum Bifocal. Furthermore, all visual functions of the 10 test persons were clearly reduced with all 3 multifocal contact lenses. A correlation between the "preferred contact lens and the detailed subjective acceptance" and/or the "subjective acceptance and the functional measurements" could not be proven as statistically significant. PMID:8502460

  8. Operation of the adaptive optics system at the Large Binocular Telescope Observatory

    Science.gov (United States)

    Miller, Douglas L.; Guerra, Juan Carlos; Boutsia, Konstantina; Fini, Luca; Argomedo, Javier; Biddick, Chris; Agapito, Guido; Arcidiacono, Carmelo; Briguglio, Runa; Brusa, Guido; Busoni, Lorenzo; Esposito, Simone; Hill, John; Kulesa, Craig; McCarthy, Don; Pinna, Enrico; Puglisi, Alfio T.; Quiros-Pacheco, Fernando; Riccardi, Armando; Xompero, Marco

    2012-07-01

    The Adaptive Optics System at the Large Binocular Telescope Observatory consists of two Adaptive Secondary (ASM) mirrors and two Pyramid Wavefront sensors. The first ASM/Pyramid pair has been commissioned and is being used for science operation using the NIR camera PISCES on the right side of the binocular telescope. The left side ASM/Pyramid system is currently being commissioned, with completion scheduled for the Fall of 2012. We will discuss the operation of the first Adaptive Optics System at the LBT Observatory including interactions of the AO system with the telescope and its TCS, observational modes, user interfaces, observational scripting language, time requirement for closed loop and offsets and observing efficiency.

  9. The Search for Failed Supernovae with The Large Binocular Telescope: First Candidates

    CERN Document Server

    Gerke, J R; Stanek, K Z

    2014-01-01

    We are monitoring 27 galaxies within 10 Mpc using the Large Binocular Telescope to search for failed supernovae (SNe), massive stars that collapse to form a black hole without a SN explosion. This sample yielded 3 successful SNe during the 4 year survey period. We search for stars that have "vanished" over the course of our survey, by examining all stars showing a decrease in luminosity of $\\Delta \

  10. Camera Calibration Method of Medical Robot Positioning System Based on Binocular Vision

    OpenAIRE

    Dong Feng; Sun Li-Ning; Ru Chang-Hai

    2013-01-01

    The medical robot positioning system plays an important role in the precise radiotherapy, so the study proposes the measure system based binocular vision to reduce the patient=s setup errors for the initial positioning rapidly and accurately. In order to get higher positioning accuracy, the study proposes a new non-contact camera calibration method based on planar and 3D checkerboard calibration templates. The experimental results show that camera calibrati...

  11. Do we really know the prevalence of accomodative and nonstrabismic binocular dysfunctions?

    OpenAIRE

    Cacho Martínez, Pilar; García Muñoz, Ángel; Ruiz Cantero, María Teresa

    2011-01-01

    Purpose: To determine the scientific evidence about the prevalence of accommodative and nonstrabismic binocular anomalies. Methods: We carried out a systematic review of studies published between 1986 and 2009, analysing the MEDLINE, CINAHL, FRANCIS and PsycINFO databases. We considered admitting those papers related to prevalence in paediatric and adult populations. We identified 660 articles and 10 papers met the inclusion criteria. Results: There is a wide range of prevalence, particularly...

  12. Prevalence of Accommodative and Non-Strabismic Binocular Anomalies in a Puerto Rican Pediatric Population

    OpenAIRE

    Stefania M. Paniccia, OD, MS; Angel Romero Ayala, OD

    2015-01-01

    Background: There exists a considerable void in the literature of studies that examine the prevalence of non-strabismic binocular and accommodative disorders in the pediatric population of Puerto Rico. The purpose of this retrospective study was to fill this void by performing a comprehensive record review of the pediatric clinical population of the InterAmerican University College of Optometry satellite clinics. Methods: This study was performed using a random selection of 593 existing h...

  13. The wavelet transform and the suppression theory of binocular vision for stereo image compression

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, W.D. Jr [Argonne National Lab., IL (United States); Kenyon, R.V. [Illinois Univ., Chicago, IL (United States)

    1996-08-01

    In this paper a method for compression of stereo images. The proposed scheme is a frequency domain approach based on the suppression theory of binocular vision. By using the information in the frequency domain, complex disparity estimation techniques can be avoided. The wavelet transform is used to obtain a multiresolution analysis of the stereo pair by which the subbands convey the necessary frequency domain information.

  14. Synchronizing retinal activity in both eyes disrupts binocular map development in the optic tectum

    OpenAIRE

    Brickley, S.; Dawes, E.; Keating, M; Grant, S

    1998-01-01

    Spatiotemporal correlations in the pattern of spontaneous and evoked retinal ganglion cell (RGC) activity are believed to influence the topographic organization of connections throughout the developing visual system. We have tested this hypothesis by examining the effects of interfering with these potential activity cues during development on the functional organization of binocular maps in the Xenopus frog optic tectum. Paired recordings combined with cross-correlation analyses demonstrated ...

  15. Voluntary binocular gaze-shifts in the plane of regard: Dynamics of version and vergence

    OpenAIRE

    Collewijn, Han; Erkelens, Dirk Willem; Steinman, Robert

    1995-01-01

    textabstractWe studied the dynamics of voluntary, horizontal, binocular gaze-shifts between pairs of continuously visible, real three-dimensional targets. Subjects were stabilized on a biteboard to allow full control of target angles, which were made to differ only in distance (pure vergence), only in direction (pure version; conjugate saccades) or in both distance and direction (disjunctive saccades). A wide range of changes in vergence (0-25 deg) and version (0-65 deg) was recorded to study...

  16. Image-based grouping during binocular rivalry is dictated by eye-of-origin.

    Directory of Open Access Journals (Sweden)

    Sjoerd M Stuit

    Full Text Available Prolonged viewing of dichoptically presented images with different content results in perceptual alternations known as binocular rivalry. This phenomenon is thought to be the result of competition at a local level, where local rivalry zones interact to give rise to a single, global dominant percept. Certain perceived combinations that result from this local competition are known to last longer than others, which is referred to as grouping during binocular rivalry. In recent years, the phenomenon has been suggested to be the result of competition at both eye- and image-based processing levels, although the exact contribution from each level remains elusive. Here we use a paradigm designed specifically to quantify the contribution of eye- and image-based processing to grouping during rivalry. In this paradigm we used sine-wave gratings as well as upright and inverted faces, with and without binocular disparity-based occlusion. These stimuli and conditions were used because they are known to result in processing at different stages throughout the visual processing hierarchy. Specifically, more complex images were included in order to maximize the potential contribution of image-based grouping. In spite of this, our results show that increasing image complexity did not lead to an increase in the contribution of image-based processing to grouping during rivalry. In fact, the results show that grouping was primarily affected by the eye-of-origin of the image parts, irrespective of stimulus type. We suggest that image content affects grouping during binocular rivalry at low-level processing stages, where it is intertwined with eye-of-origin information.

  17. Influence of retinal image shifts and extra-retinal eye movement signals on binocular rivalry alternations

    OpenAIRE

    Kalisvaart, Joke P.; Jeroen Goossens

    2013-01-01

    Previous studies have indicated that saccadic eye movements correlate positively with perceptual alternations in binocular rivalry, presumably because the foveal image changes resulting from saccades, rather than the eye movement themselves, cause switches in awareness. Recently, however, we found evidence that retinal image shifts elicit so-called onset rivalry and not percept switches as such. These findings raise the interesting question whether onset rivalry may account for correlations b...

  18. Removal of monocular interactions equates rivalry behavior for monocular, binocular, and stimulus rivalries

    OpenAIRE

    van Boxtel, J.J.A.; Knapen, T.H.J.; Erkelens, C. J.; Ee, R

    2008-01-01

    When the two eyes are presented with conflicting stimuli, perception starts to fluctuate over time (i.e., binocular rivalry). A similar fluctuation occurs when two patterns are presented to a single eye (i.e., monocular rivalry), or when they are swapped rapidly and repeatedly between the eyes (i.e., stimulus rivalry). Although all these cases lead to rivalry, in quantitative terms these modes of rivalry are generally found to differ significantly. We studied these different modes of rivalry ...

  19. Stereopsis and binocular rivalry are based on perceived rather than physical orientations

    OpenAIRE

    Chopin, Adrien; Mamassian, Pascal; Blake, Randolph

    2012-01-01

    Binocular rivalry is an intriguing phenomenon: when different images are displayed to the two eyes, perception alternates between these two images. What determines whether two monocular images engage in fusion or in rivalry: the physical difference between these images or the difference between the percepts resulting from the images? We investigated that question by measuring the interocular difference of grid orientation needed to produce a transition from fusion to rivalry and by changing t...

  20. MEG phase follows conscious perception during binocular rivalry induced by visual stream segregation

    OpenAIRE

    Petrovic, Sanja; Srinivasan, Ramesh

    2005-01-01

    We have investigated an unusual form of binocular rivalry between two images that are flickered one to each eye, but are never presented simultaneously to the observer. The images are presented in alternation, with a brief dark period between the images. When the flicker frequency was below 5 Hz, the subjects primarily experienced a unitary flicker that alternated between the two images. When the flicker frequency was above 5 Hz, the subjects primarily experienced two single-image flickers th...

  1. Disparity vergence responses before versus after repetitive vergence therapy in binocularly normal controls.

    Science.gov (United States)

    Talasan, Henry; Scheiman, Mitchell; Li, Xiaobo; Alvarez, Tara L

    2016-01-01

    This study sought to determine whether significant changes would be observed between vergence eye movements before and after 12 hr of repetitive vergence therapy (1 hr per day on different days) in subjects with normal binocular vision compared to controls. Disparity vergence responses from 23 subjects were studied. An assessment protocol that minimized the influence of the near dissociated phoria on the disparity vergence system was designed. The following parameters were quantified for the responses: latency, time to peak velocity, settling time, peak velocity, and accuracy (difference between the response and stimulus amplitudes). The following outcomes were observed when comparing the results after vergence therapy to the baseline measurements: (a) near point of convergence and near dissociated phoria did not significantly change (p > 0.15); (b) latency, time to peak velocity, and settling time significantly decreased (p ≤ 0.01); and (c) accuracy significantly improved (p eye movement responses from subjects with normal binocular vision can be improved after vergence therapy. These methods can be utilized within future studies to quantitatively assess vergence therapy techniques for patients with binocular dysfunction. PMID:26762276

  2. Ecomorphology of orbit orientation and the adaptive significance of binocular vision in primates and other mammals.

    Science.gov (United States)

    Heesy, Christopher P

    2008-01-01

    Primates are characterized by forward-facing, or convergent, orbits and associated binocular field overlap. Hypotheses explaining the adaptive significance of these traits often relate to ecological factors, such as arboreality, nocturnal visual predation, or saltatory locomotion in a complex nocturnal, arboreal environment. This study re-examines the ecological factors that are associated with high orbit convergence in mammals. Orbit orientation data were collected for 321 extant taxa from sixteen orders of metatherian (marsupial) and eutherian mammals. These taxa were coded for activity pattern, degree of faunivory, and substrate preference. Results demonstrate that nocturnal and cathemeral mammals have significantly more convergent orbits than diurnal taxa, both within and across orders. Faunivorous eutherians (both nocturnal and diurnal) have higher mean orbit convergence than opportunistically foraging or non-faunivorous taxa. However, substrate preference is not associated with higher orbit convergence and, by extension, greater binocular visual field overlap. These results are consistent with the hypothesis that mammalian predators evolved higher orbit convergence, binocular vision, and stereopsis to counter camouflage in prey inhabiting a nocturnal environment. Strepsirhine primates have a range of orbit convergence values similar to nocturnal or cathemeral predatory non-primate mammals. These data are entirely consistent with the nocturnal visual predation hypothesis of primate origins. PMID:17878718

  3. Congruent tactile stimulation reduces the strength of visual suppression during binocular rivalry.

    Science.gov (United States)

    Lunghi, Claudia; Alais, David

    2015-01-01

    Presenting different images to each eye triggers 'binocular rivalry' in which one image is visible and the other suppressed, with the visible image alternating every second or so. We previously showed that binocular rivalry between cross-oriented gratings is altered when the fingertip explores a grooved stimulus aligned with one of the rivaling gratings: the matching visual grating's dominance duration was lengthened and its suppression duration shortened. In a more robust test, we here measure visual contrast sensitivity during rivalry dominance and suppression, with and without exploration of the grooved surface, to determine if rivalry suppression strength is modulated by touch. We find that a visual grating undergoes 45% less suppression when observers touch an aligned grating, compared to a cross-oriented one. Touching an aligned grating also improved visual detection thresholds for the 'invisible' suppressed grating by 2.4 dB, relative to a vision-only condition. These results show that congruent haptic stimulation prevents a visual stimulus from becoming deeply suppressed in binocular rivalry. Moreover, because congruent touch acted on the phenomenally invisible grating, this visuo-haptic interaction must precede awareness and likely occurs early in visual processing. PMID:25797534

  4. Comparison of binocular through-focus visual acuity with monovision and a small aperture inlay.

    Science.gov (United States)

    Schwarz, Christina; Manzanera, Silvestre; Prieto, Pedro M; Fernández, Enrique J; Artal, Pablo

    2014-10-01

    Corneal small aperture inlays provide extended depth of focus as a solution to presbyopia. As this procedure is becoming more popular, it is interesting to compare its performance with traditional approaches, such as monovision. Here, binocular visual acuity was measured as a function of object vergence in three subjects by using a binocular adaptive optics vision analyzer. Visual acuity was measured at two luminance levels (photopic and mesopic) under several optical conditions: 1) natural vision (4 mm pupils, best corrected distance vision), 2) pure-defocus monovision ( + 1.25 D add in the nondominant eye), 3) small aperture monovision (1.6 mm pupil in the nondominant eye), and 4) combined small aperture and defocus monovision (1.6 mm pupil and a + 0.75 D add in the nondominant eye). Visual simulations of a small aperture corneal inlay suggest that the device extends DOF as effectively as traditional monovision in photopic light, in both cases at the cost of binocular summation. However, individual factors, such as aperture centration or sensitivity to mesopic conditions should be considered to assure adequate visual outcomes. PMID:25360355

  5. Loss of binocular vision as direct cause for misrouting of temporal retinal fibers in albinism.

    Science.gov (United States)

    Banihani, Saleh M

    2015-10-01

    In humans, the nasal retina projects to the contralateral hemisphere, whereas the temporal retina projects ipsilaterally. The nasotemporal line that divides the retina into crossed and uncrossed parts coincides with the vertical meridian through the fovea. This normal projection of the retina is severely altered in albinism, in which the nasotemporal line shifted into the temporal retina with temporal retinal fibers cross the midline at the optic chiasm. This study proposes the loss of binocular vision as direct cause for misrouting of temporal retinal fibers and shifting of the nasotemporal line temporally in albinism. It is supported by many observations that clearly indicate that loss of binocular vision causes uncrossed retinal fibers to cross the midline. This hypothesis may alert scientists and clinicians to find ways to prevent or minimize the loss of binocular vision that may occur in some diseases such as albinism and early squint. Hopefully, this will minimize the misrouting of temporal fibers and improve vision in such diseases. PMID:26163060

  6. Corneal Transplantation in Disease Affecting Only One Eye: Does It Make a Difference to Habitual Binocular Viewing?

    Directory of Open Access Journals (Sweden)

    Praveen K Bandela

    Full Text Available Clarity of the transplanted tissue and restoration of visual acuity are the two primary metrics for evaluating the success of corneal transplantation. Participation of the transplanted eye in habitual binocular viewing is seldom evaluated post-operatively. In unilateral corneal disease, the transplanted eye may remain functionally inactive during binocular viewing due to its suboptimal visual acuity and poor image quality, vis-à-vis the healthy fellow eye.This study prospectively quantified the contribution of the transplanted eye towards habitual binocular viewing in 25 cases with unilateral transplants [40yrs (IQR: 32-42yrs and 25 age-matched controls [30yrs (25-37yrs]. Binocular functions including visual field extent, high-contrast logMAR acuity, suppression threshold and stereoacuity were assessed using standard psychophysical paradigms. Optical quality of all eyes was determined from wavefront aberrometry measurements. Binocular visual field expanded by a median 21% (IQR: 18-29% compared to the monocular field of cases and controls (p = 0.63. Binocular logMAR acuity [0.0 (0.0-0.0] almost always followed the fellow eye's acuity [0.00 (0.00 --0.02] (r = 0.82, independent of the transplanted eye's acuity [0.34 (0.2-0.5] (r = 0.04. Suppression threshold and stereoacuity were poorer in cases [30.1% (13.5-44.3%; 620.8arc sec (370.3-988.2arc sec] than in controls [79% (63.5-100%; 16.3arc sec (10.6-25.5arc sec] (p<0.001. Higher-order wavefront aberrations of the transplanted eye [0.34μ (0.21-0.51μ] were higher than the fellow eye [0.07μ (0.05-0.11μ] (p<0.001 and their reduction with RGP contact lenses [0.09μ (0.08-0.12μ] significantly improved the suppression threshold [65% (50-72%] and stereoacuity [56.6arc sec (47.7-181.6arc sec] (p<0.001.In unilateral corneal disease, the transplanted eye does participate in gross binocular viewing but offers limited support to fine levels of binocularity. Improvement in the transplanted eye's optics

  7. Corneal Transplantation in Disease Affecting Only One Eye: Does It Make a Difference to Habitual Binocular Viewing?

    Science.gov (United States)

    Bandela, Praveen K.; Satgunam, PremNandhini; Garg, Prashant; Bharadwaj, Shrikant R.

    2016-01-01

    Background Clarity of the transplanted tissue and restoration of visual acuity are the two primary metrics for evaluating the success of corneal transplantation. Participation of the transplanted eye in habitual binocular viewing is seldom evaluated post-operatively. In unilateral corneal disease, the transplanted eye may remain functionally inactive during binocular viewing due to its suboptimal visual acuity and poor image quality, vis-à-vis the healthy fellow eye. Methods and Findings This study prospectively quantified the contribution of the transplanted eye towards habitual binocular viewing in 25 cases with unilateral transplants [40yrs (IQR: 32–42yrs) and 25 age-matched controls [30yrs (25–37yrs)]. Binocular functions including visual field extent, high-contrast logMAR acuity, suppression threshold and stereoacuity were assessed using standard psychophysical paradigms. Optical quality of all eyes was determined from wavefront aberrometry measurements. Binocular visual field expanded by a median 21% (IQR: 18–29%) compared to the monocular field of cases and controls (p = 0.63). Binocular logMAR acuity [0.0 (0.0–0.0)] almost always followed the fellow eye’s acuity [0.00 (0.00 –-0.02)] (r = 0.82), independent of the transplanted eye’s acuity [0.34 (0.2–0.5)] (r = 0.04). Suppression threshold and stereoacuity were poorer in cases [30.1% (13.5–44.3%); 620.8arc sec (370.3–988.2arc sec)] than in controls [79% (63.5–100%); 16.3arc sec (10.6–25.5arc sec)] (p<0.001). Higher-order wavefront aberrations of the transplanted eye [0.34μ (0.21–0.51μ)] were higher than the fellow eye [0.07μ (0.05–0.11μ)] (p<0.001) and their reduction with RGP contact lenses [0.09μ (0.08–0.12μ)] significantly improved the suppression threshold [65% (50–72%)] and stereoacuity [56.6arc sec (47.7–181.6arc sec)] (p<0.001). Conclusions In unilateral corneal disease, the transplanted eye does participate in gross binocular viewing but offers limited support

  8. Binocular summation and other forms of non-dominant eye contribution in individuals with strabismic amblyopia during habitual viewing.

    Directory of Open Access Journals (Sweden)

    Brendan T Barrett

    Full Text Available BACKGROUND: Adults with amblyopia ('lazy eye', long-standing strabismus (ocular misalignment or both typically do not experience visual symptoms because the signal from weaker eye is given less weight than the signal from its fellow. Here we examine the contribution of the weaker eye of individuals with strabismus and amblyopia with both eyes open and with the deviating eye in its anomalous motor position. METHODOLOGY/RESULTS: The task consisted of a blue-on-yellow detection task along a horizontal line across the central 50 degrees of the visual field. We compare the results obtained in ten individuals with strabismic amblyopia with ten visual normals. At each field location in each participant, we examined how the sensitivity exhibited under binocular conditions compared with sensitivity from four predictions, (i a model of binocular summation, (ii the average of the monocular sensitivities, (iii dominant-eye sensitivity or (iv non-dominant-eye sensitivity. The proportion of field locations for which the binocular summation model provided the best description of binocular sensitivity was similar in normals (50.6% and amblyopes (48.2%. Average monocular sensitivity matched binocular sensitivity in 14.1% of amblyopes' field locations compared to 8.8% of normals'. Dominant-eye sensitivity explained sensitivity at 27.1% of field locations in amblyopes but 21.2% in normals. Non-dominant-eye sensitivity explained sensitivity at 10.6% of field locations in amblyopes but 19.4% in normals. Binocular summation provided the best description of the sensitivity profile in 6/10 amblyopes compared to 7/10 of normals. In three amblyopes, dominant-eye sensitivity most closely reflected binocular sensitivity (compared to two normals and in the remaining amblyope, binocular sensitivity approximated to an average of the monocular sensitivities. CONCLUSIONS: Our results suggest a strong positive contribution in habitual viewing from the non-dominant eye in

  9. Analysis of the Difference between the Normal Vision and the Experiencing Cataract Vision on Binocular Color Fusion Limit

    Directory of Open Access Journals (Sweden)

    Shi Wang

    2015-10-01

    Full Text Available The optical instruments design for binocular vision has become an earnest demand towards the arrival of an ageing society. It is necessary to measure how color difference between left and right images by elderly people, which the color rivalry occurs. In this study, we measured the limit of binocular color fusion in the normal vision and the cataract experiencing vision which is aiming to simulate the elderly vision. The result shows that the color fusion limit curve in cataract experiencing vision are very similar with those in normal vision. Compared with the binocular color fusion limit in normal vision Δλdn, the binocular color fusion limit in cataract experiencing vision Δλdc is approximately 3~39nm increased on the central vision, 4~22nm on the retinal eccentricity of 3°, 5~23nm on the retinal eccentricity of 6°, and 5~24nm on the retinal eccentricity of 9°. The results also reveal that a similar limit is observed in the range of 520~560nm in both normal and cataract experiencing visions, which might give some potential evidences for designing 3D equipment. In addition, the minimum value of the binocular color fusion limit exists at 590nm either in the normal vision or the cataract experiencing vision during all retinal eccentricities

  10. Effect of Near Work on Binocular Vision Measurements in Adults with Convergence Insufficiency

    Directory of Open Access Journals (Sweden)

    Yi Pang, OD, PhD

    2015-02-01

    Full Text Available Background: Convergence insufficiency (CI is a common binocular vision disorder. A common characteristic of CI is that patients have more symptoms, such as eyestrain and headache, after close work. The purpose of this study was to determine whether 30 minutes of reading affects the binocular and accommodative measurements used in the diagnosis of CI. Methods: Eighteen normal adult subjects and eighteen adult CI subjects (symptomatic and asymptomatic were recruited. None of the CI subjects had accommodative insufficiency. The following measurements were made: distance and near cover test, near point of convergence (NPC with accommodative target (AT, NPC with transilluminator and red lens (RL, near positive fusional vergence (PFV, and accommodative amplitude. Subjects were then asked to read a book for 30 minutes, immediately followed by repeated administration of the above tests by the same examiner. Statistical analysis was performed using a Student’s paired t-test to compare the measurements before and after reading. Results: In the CI group, the mean phoria at near changed from 7.06Δ exophoria to 6.56Δ exophoria after reading for 30 minutes. Mean NPC break with AT changed from 9.58 cm to 11.25 cm. With RL, an average increase from 12.56 cm to 13.93 cm occurred for NPC break. Mean PFV break decreased from 17.22Δ to 15.56Δ . Mean amplitude of accommodation (OD changed from 7.46 to 7.56 diopters. Only the change in NPC break with AT after reading was statistically significant (P = 0.007. There were minimal changes in clinical measurements after reading in the normal subjects. Conclusion: Half an hour of reading had a statistically significant effect on the NPC break with AT but not on other binocular vision measurements in subjects with CI. It is unknown whether a longer period of reading would have a greater effect.

  11. A Standardized Procedure and Normative Values for Measuring Binocular Dynamic Visual Acuity

    Directory of Open Access Journals (Sweden)

    Amanda Miskewicz-Zastrow, OD

    2015-04-01

    Full Text Available Background: Binocular dynamic visual acuity (BDVA is the ability to differentiate fine details in a moving object such as seams on a pitched baseball or the rotation of a tennis ball, both of which can travel up to speeds exceeding 100 miles per hour. BDVA is one of many binocular visual measurements to examine binocular function. This study was designed to provide a standardized procedure for measuring BDVA and normal values for a sample population. Previous studies have used different techniques for measurement, and thus have no normative data for comparison. Methods: The BCVA attachment to the Bernell Rotation Trainer was used to measure BDVA in 22 subjects (10 females and 12 males between the ages of 23 and 30. Only subjects with a refractive error between +1.00 D and -7.00 D (spherical equivalent and with best corrected visual acuity of 20/20 or better were able to participate in the study. BDVA was recorded at three different rotation speeds (29 RPM, 24 RPM, and 16 RPM. At each RPM, accuracy and the time to completion of all nine lines were measured. The subjects were also asked to complete a questionnaire designed to evaluate factors that may influence the BDVA results. Results: A decrease in RPM resulted in a corresponding decrease in the subject’s completion time and an increase in accuracy. The same trend was seen when comparing males and females; however, the females’ accuracy was lower and the time was greater when compared to the males, but these were not statistically significant. Conclusions: This was the first study designed to use the Bernell Rotation Trainer to quantitatively measure BDVA in a standardized way. Our results showed similar trends in both males and females. In addition, this study provides a strong foundation for future research, such as comparing BDVA of athletes and non-athletes, or comparing athletes with different skill levels, or comparing athletes who participate in different sports.

  12. Very few exclusive percepts for contrast-modulated stimuli during binocular rivalry.

    Science.gov (United States)

    Skerswetat, Jan; Formankiewicz, Monika A; Waugh, Sarah J

    2016-04-01

    Binocular rivalry properties for contrast-modulated (CM) gratings were examined to gain insight into their locus of processing. Two orthogonally orientated gratings were presented, one to each eye. Perceptual change rates, proportions of exclusivity and mixed percepts, and mean durations were calculated. Stimuli were noiseless luminance-defined (L), luminance-modulated noise (LM) and contrast-modulated noise (CM) gratings with sizes of 1, 2 and 4deg and spatial frequencies of 4, 2 and 1c/deg, respectively. For the LM and CM gratings, binary noise was fully correlated between eyes. Maximum producible modulations were used (1.0 for CM, 0.78 for LM and 0.98 for L stimuli). In a control experiment, contrasts of LM gratings were reduced until the multiples over detection threshold were similar to those of CM stimuli. Trial durations of 120s were analyzed. Exclusive visibility decreased with increasing stimulus size regardless of the stimulus type. Even with visibilities at similar multiples above detection threshold, significantly lower proportions of exclusive percepts and perceptual changes were found for CM, compared to LM gratings. The results obtained with dichoptically presented orthogonal CM gratings are significantly different from those obtained for orthogonal gratings presented to one eye. CM stimuli therefore do engage in binocular rivalry but with different characteristics to those found for LM stimuli. These results suggest that CM stimuli are processed by a mechanism that promotes binocular combination rather than rivalry, and therefore may involve cells in a higher visual area than those that initially process LM information. PMID:26827700

  13. Neuronal convergence in early contrast vision: Binocular summation is followed by response nonlinearity and area summation

    OpenAIRE

    Meese, Tim S.; Summers, Robert J.

    2009-01-01

    We assessed summation of contrast across eyes and area at detection threshold (Ct). Stimuli were sine-wave gratings (2.5 c/deg) spatially modulated by cosine- and anticosine-phase raised plaids (0.5 c/deg components oriented at ±45°). When presented dichoptically the signal regions were interdigitated across eyes but produced a smooth continuous grating following their linear binocular sum. The average summation ratio (Ct1/([Ct1+2]) for this stimulus pair was 1.64 (4.3 dB). This was only slig...

  14. Secondary imprinting in the domestic chick: Binocular and lateralized monocular performance

    OpenAIRE

    Vallortigara, Giorgio; Regolin, Lucia; Zucca, Paolo

    2000-01-01

    Newly-hatched chicks were reared with a coloured imprinting object on day 1 of life (primary imprinting) and then with an object of a different colour (secondary imprinting) on day 2. They were then tested on day 3 for preferences between the primary and the secondary imprinting object in binocular and in monocular conditions. The main results were that (1) left-eyed chicks usually showed clearer choice than right-eyed chicks; (2) there were colour preferences that appeared to affect choice d...

  15. The Quantum-Classical and Mind-Brain Linkages: The Quantum Zeno Effect in Binocular Rivalry

    CERN Document Server

    Stapp, Henry P

    2007-01-01

    A quantum mechanical theory of the relationship between perceptions and brain dynamics based on von Neumann's theory of measurments is applied to a recent quantum theoretical treatment of binocular rivaly that makes essential use of the quantum Zeno effect to give good fits to the complex available empirical data. The often-made claim that decoherence effects in the warm, wet, noisy brain must eliminate quantum effects at the macroscopic scale pertaining to perceptions is examined, and it is argued, on the basis of fundamental principles. that the usual decoherence effects will not upset the quantum Zeno effect that is being exploited in the cited work.

  16. Monocular and binocular steady-state flicker VEPs: frequency-response functions to sinusoidal and square-wave luminance modulation.

    Science.gov (United States)

    Nicol, David S; Hamilton, Ruth; Shahani, Uma; McCulloch, Daphne L

    2011-02-01

    Steady-state VEPs to full-field flicker (FFF) using sinusoidally modulated light were compared with those elicited by square-wave modulated light across a wide range of stimulus frequencies with monocular and binocular FFF stimulation. Binocular and monocular VEPs were elicited in 12 adult volunteers to FFF with two modes of temporal modulation: sinusoidal or square-wave (abrupt onset and offset, 50% duty cycle) at ten temporal frequencies ranging from 2.83 to 58.8 Hz. All stimuli had a mean luminance of 100 cd/m(2) with an 80% modulation depth (20-180 cd/m(2)). Response magnitudes at the stimulus frequency (F1) and at the double and triple harmonics (F2 and F3) were compared. For both sinusoidal and square-wave flicker, the FFF-VEP magnitudes at F1 were maximal for 7.52 Hz flicker. F2 was maximal for 5.29 Hz flicker, and F3 magnitudes are largest for flicker stimulation from 3.75 to 7.52 Hz. Square-wave flicker produced significantly larger F1 and F2 magnitudes for slow flicker rates (up to 5.29 Hz for F1; at 2.83 and 3.75 Hz for F2). The F3 magnitudes were larger overall for square-wave flicker. Binocular FFF-VEP magnitudes are larger than those of monocular FFF-VEPs, and the amount of this binocular enhancement is not dependant on the mode of flicker stimulation (mean binocular: monocular ratio 1.41, 95% CI: 1.2-1.6). Binocular enhancement of F1 for 21.3 Hz flicker was increased to a factor of 2.5 (95% CI: 1.8-3.5). In the healthy adult visual system, FFF-VEP magnitudes can be characterized by the frequency-response functions of F1, F2 and F3. Low-frequency roll-off in the FFF-VEP magnitudes is greater for sinusoidal flicker than for square-wave flicker for rates ≤ 5.29 Hz; magnitudes for higher-frequency flicker are similar for the two types of flicker. Binocular FFF-VEPs are larger overall than those recorded monocularly, and this binocular summation is enhanced at 21.3 Hz in the mid-frequency range. PMID:21279419

  17. Evaluation of a four month rehabilitation program for stroke patients with balance problems and binocular visual dysfunction

    DEFF Research Database (Denmark)

    Schow, Trine; Harris, Paul; Teasdale, Thomas William;

    2016-01-01

    Trine Schow, Paul Harris, Thomas William Teasdale, Morten Arendt Rasmussen. Evaluation of a four month rehabilitation program for stroke patients with balance problems and binocular visual dysfunction. NeuroRehabilitation. 2016 Apr 6;38(4):331-41. doi: 10.3233/NRE-161324.......Trine Schow, Paul Harris, Thomas William Teasdale, Morten Arendt Rasmussen. Evaluation of a four month rehabilitation program for stroke patients with balance problems and binocular visual dysfunction. NeuroRehabilitation. 2016 Apr 6;38(4):331-41. doi: 10.3233/NRE-161324....

  18. A deep Large Binocular Telescope view of the Canes Venatici I dwarf galaxy

    CERN Document Server

    Martin, Nicolas F; De Jong, Jelte T A; Rix, Hans-Walter; Bell, Eric F; Sand, David J; Hill, John M; Kochanek, Christopher S; Thompson, David; Burwitz, Vadim; Giallongo, Emanuele; Ragazzoni, Roberto; Diolaiti, Emiliano; Gasparo, Federico; Grazian, Andrea; Pedichini, Fernando; Bechtold, Jill

    2007-01-01

    We present the first deep color-magnitude diagram of the Canes Venatici I (CVnI) dwarf galaxy from observations with the wide field Large Binocular Camera of the Large Binocular Telescope. Reaching down to the main-sequence turnoff of the oldest stars, it reveals a dichotomy in the stellar populations of CVnI: it harbors an old (>~ 10 Gyr), metal-poor ([Fe/H] ~ -2.0) and spatially extended population along with a much younger (~1.4-2.0 Gyr), 0.5 dex more metal-rich, and spatially more concentrated population. These young stars are also offset by ~100 pc to the East of the center of the galaxy. The data suggest that this young population should be identified with the kinematically cold stellar component found by Ibata et al. (2006). CVnI therefore follows the behavior of the other remote MW dwarf spheroidals which all contain intermediate age and/or young populations: a complex star formation history is possible in extremely low-mass galaxies.

  19. Measurement error analysis of three dimensional coordinates of tomatoes acquired using the binocular stereo vision

    Science.gov (United States)

    Xiang, Rong

    2014-09-01

    This study analyzes the measurement errors of three dimensional coordinates of binocular stereo vision for tomatoes based on three stereo matching methods, centroid-based matching, area-based matching, and combination matching to improve the localization accuracy of the binocular stereo vision system of tomato harvesting robots. Centroid-based matching was realized through the matching of the feature points of centroids of tomato regions. Area-based matching was realized based on the gray similarity between two neighborhoods of two pixels to be matched in stereo images. Combination matching was realized using the rough disparity acquired through centroid-based matching as the center of the dynamic disparity range which was used in area-based matching. After stereo matching, three dimensional coordinates of tomatoes were acquired using the triangle range finding principle. Test results based on 225 stereo images captured at the distances from 300 to 1000 mm of 3 tomatoes showed that the measurement errors of x coordinates were small, and can meet the need of harvesting robots. However, the measurement biases of y coordinates and depth values were large, and the measurement variation of depth values was also large. Therefore, the measurement biases of y coordinates and depth values, and the measurement variation of depth values should be corrected in the future researches.

  20. Current Status of the Facility Instrumentation Suite at The Large Binocular Telescope Observatory

    CERN Document Server

    Rothberg, Barry; Edwards, Michelle L; Hill, John M; Thompson, David; Veillet, Christian; Wagner, R Mark

    2016-01-01

    We review the current status of the facility instrumentation for the Large Binocular Telescope (LBT). The LBT has 2x 8.4m primary mirrors on a single mount with an effective collecting area of 11.8m or 23m when interferometrically combined. The facility instruments are: 1) the Large Binocular Cameras (LBCs), each with a 23'x25' field of view (FOV). The blue and red optimized optical LBCs are mounted at the prime focus of the left and right primary mirrors, respectively. The filter suite of the two LBCs covers 0.3-1.1{\\mu}m, including the new TiO (0.78{\\mu}m) and CN (0.82{\\mu}m) filters; 2) the Multi-Object Double Spectrograph (MODS), two identical optical spectrographs each mounted at a straight through f/15 Gregorian mount. MODS-1 & -2 can do imaging with Sloan filters and medium resolution (R~2000) spectroscopy, each with 24 interchangeable masks (multi-object or longslit) over a 6'x6' FOV. Each MODS is capable of blue (0.32-0.6{\\mu}m) and red (0.5-1.05{\\mu}m) wavelength only coverage or, using a dichro...

  1. Enhancement display of veins distribution based on binocular vision and image fusion technology

    Science.gov (United States)

    Liu, Peng; Di, Si; Jin, Jian; Bai, Liping

    2014-11-01

    The capture and display of veins distribution is an important issue for some applications, such as medical diagnosis and identification. Therefore, it has become a popular topic in the field of biomedical imaging. Usually, people capture the veins distribution by infrared imaging, but the display result is similar with that of a gray picture and the color and details of skin cannot be remained. To some degree, it is unreal for doctors. In this paper, we develop a binocular vision system to carry out the enhancement display of veins under the condition of keeping actual skin color. The binocular system is consisted of two adjacent cameras. A visible band filter and an infrared band filter are placed in front of the two lenses, respectively. Therefore, the pictures of visible band and infrared band can be captured simultaneously. After that, a new fusion process is applied to the two pictures, which related to histogram mapping, principal component analysis (PCA) and modified bilateral filter fusion. The final results show that both the veins distribution and the actual skin color of the back of the hand can be clearly displayed. Besides, correlation coefficient, average gradient and average distortion are selected as the parameters to evaluate the image quality. By comparing the parameters, it is evident that our novel fusion method is prior to some popular fusion methods such as Gauss filter fusion, Intensity-hue-saturation (HIS) fusion and bilateral filter fusion.

  2. The relationship between binocular vision symptoms and near point of convergence

    Directory of Open Access Journals (Sweden)

    Momeni-Moghaddam Hamed

    2013-01-01

    Full Text Available Aim and Background: Due to the relatively high prevalence of binocular vision anomalies, a regular examination including tests for assessment and determination of these anomalies is necessary. The aim of this study was to assess the relationship between near point of convergence (NPC and near binocular vision symptoms and finding of an NPC cutoff point for symptoms in university students. Materials and Methods: In this cross-sectional study, 124 students of different majors of Zahedan University of Medical Sciences were randomly selected. If they met the inclusion criteria, they were divided into two groups (symptomatic and asymptomatic according to the convergence insufficiency symptom survey questionnaire. For NPC measurement, a small isolated letter "E" of approximately 20/30 size on a metal rod was used. After data collection, data were analyzed in SPSS.17 software (SPSS for Windows, SPSS Inc., Chicago, IL using descriptive and analytical statistics, including Mann-Whitney U test and receiver operating characteristic (ROC curve. Results: The mean NPC findings in the symptomatic and asymptomatic groups were 11.7 ± 5.0 and 8.4 ± 3.4 cm, respectively, with a significant difference between the two groups (P < 0.001. The ROC curve suggests an NPC cutoff point of 9.5 cm for the presence of symptoms with the testing procedures used in this study. Conclusion : The determination of NPC is helpful in the differentiation of symptomatic from asymptomatic subjects.

  3. On-sky single-mode fiber coupling measurements at the Large Binocular Telescope

    CERN Document Server

    Bechter, Andrew; Ketterer, Ryan; Crepp, Justin R; Reynolds, Robert O; Bechter, Eric; Hinz, Philip; Pedichini, Fernando; Foley, Michael; Runburg, Elliott; Onuma, Eleanya; Gaudi, Scott; Micela, Giuseppina; Pagano, Isabella; Woodward, Charles E

    2016-01-01

    The demonstration of efficient single-mode fiber (SMF) coupling is a key requirement for the development of a compact, ultra-precise radial velocity (RV) spectrograph. iLocater is a next generation instrument for the Large Binocular Telescope (LBT) that uses adaptive optics (AO) to inject starlight into a SMF. In preparation for commissioning iLocater, a prototype SMF injection system was installed and tested at the LBT in the Y-band (0.970-1.065 $\\mu$m). This system was designed to verify the capability of the LBT AO system as well as characterize on-sky SMF coupling efficiencies. SMF coupling was measured on stars with variable airmasses, apparent magnitudes, and seeing conditions for six half-nights using the Large Binocular Telescope Interferometer. We present the overall optical and mechanical performance of the SMF injection system, including details of the installation and alignment procedure. A particular emphasis is placed on analyzing the instrument's performance as a function of telescope elevation...

  4. Surface area of early visual cortex predicts individual speed of traveling waves during binocular rivalry.

    Science.gov (United States)

    Genç, Erhan; Bergmann, Johanna; Singer, Wolf; Kohler, Axel

    2015-06-01

    Binocular rivalry ensues when different images are presented to the 2 eyes with conscious perception alternating between the possible interpretations. For large rivalry displays, perceptual transitions are initiated at one location and spread to other parts of the visual field, a phenomenon termed "traveling wave." Previous studies investigated the underlying neural mechanisms of the traveling wave and surmised that primary visual cortex might play an important role. We used magnetic resonance imaging and behavioral measures in humans to explore how interindividual differences in observers' subjective experience of the wave are related to anatomical characteristics of cortical regions. We measured wave speed in participants and confirmed the long-term stability of the individual values. Retinotopic mapping was employed to delineate borders of visual areas V1-V3 in order to determine surface area and cortical thickness in those regions. Only the surface areas of V1 and V2, but not V3 showed a correlation with wave speed. For individuals with larger V1/V2 area, the traveling wave needed longer to spread across the same distance in visual space. Our results highlight the role of early visual areas in mediating binocular rivalry and suggest possible mechanisms for the correlation between surface area and the traveling waves. PMID:24334918

  5. Simulating binocular vision for no-reference 3D visual quality measurement.

    Science.gov (United States)

    Zhou, Wu-Jie; Yu, Lu; Wu, Ming-Wei

    2015-09-01

    Perceptual quality measurement of three-dimensional (3D) visual signals has become a fundamental challenge in 3D imaging fields. This paper proposes a novel no-reference (NR) 3D visual quality measurement (VQM) metric that uses simulations of the primary visual cortex (V1) of binocular vision. As the major technical contribution of this study, perceptual properties of simple and complex cells are considered for NR 3D-VQM. More specifically, the metric simulates the receptive fields of simple cells (one class of V1 neurons) using Gaussian derivative functions, and the receptive fields of complex cells (the other class of V1 neurons) using disparity energy responses and binocular rivalry responses. Subsequently, various quality-aware features are extracted from the primary visual cortex; these will change in the presence of distortions. Finally, those features are mapped to the subjective quality score of the distorted 3D visual signal by using support vector regression (SVR). Experiments on two publicly available 3D databases confirm the effectiveness of our proposed metric, compared to the relevant full-reference (FR) and NR metrics. PMID:26368467

  6. Toward a Blind Deep Quality Evaluator for Stereoscopic Images Based on Monocular and Binocular Interactions.

    Science.gov (United States)

    Shao, Feng; Tian, Weijun; Lin, Weisi; Jiang, Gangyi; Dai, Qionghai

    2016-05-01

    During recent years, blind image quality assessment (BIQA) has been intensively studied with different machine learning tools. Existing BIQA metrics, however, do not design for stereoscopic images. We believe this problem can be resolved by separating 3D images and capturing the essential attributes of images via deep neural network. In this paper, we propose a blind deep quality evaluator (DQE) for stereoscopic images (denoted by 3D-DQE) based on monocular and binocular interactions. The key technical steps in the proposed 3D-DQE are to train two separate 2D deep neural networks (2D-DNNs) from 2D monocular images and cyclopean images to model the process of monocular and binocular quality predictions, and combine the measured 2D monocular and cyclopean quality scores using different weighting schemes. Experimental results on four public 3D image quality assessment databases demonstrate that in comparison with the existing methods, the devised algorithm achieves high consistent alignment with subjective assessment. PMID:26960225

  7. Flight testing of a binocular bisensor HMD for helicopter: some human factors aspects

    Science.gov (United States)

    Leger, Alain; Roumes, Corinne; Bergeaud, J. M.; Dareoux, P.; Gardelle, C.

    1998-08-01

    The need for night vision system in military helicopter has been recognized for many years now. Besides fixed FLIR and night vision goggles, helmet-mounted systems coupled with head-slaved IR sensor have been introduced during the last decade in modern attack helicopters. Monocular HMDs have been fielded on the AH-64 and used in operation. Human factors aspects pertaining to such night vision devices has been extensively reviewed and published. Though, full scale flight tests of binocular HMDs with integrated I2 and head coupled IR sensors have rarely been reported. A binocular helmet, with a 40 degree full overlap FOV has been developed under a contract of the French DGA. Two image intensifiers tubes located on each side of the head are integrated on the helmet, which also has full raster and stroke capacity. Both images are projected on the visor of the helmet and collimated to infinity. IR sensor imagery and navigation system are coupled to the helmet using an electro-magnetic head-tracker. Test flight of the helmet have been conducted by the French Flight Test Center on specially equipped Puma test-bed aircraft. Approximately 150 flight hours have been devoted to testing of the helmet, either with I2 and IR sensors.

  8. Difference in the binocular rivalry rate between depressive episodes and remission.

    Science.gov (United States)

    Jia, Ting; Ye, Xing; Wei, Qiang; Xie, Wen; Cai, Chunlan; Mu, Jingjing; Dong, Yi; Hu, Panpan; Hu, Xinglong; Tian, Yanghua; Wang, Kai

    2015-11-01

    Binocular rivalry refers to a phenomenon in which, when different images are presented to each eye simultaneously, perception alternates spontaneously between monocular views rather than being a superposition of the two images. Recently, the involvement of serotonin systems has been reported to be related to the phenomenon. There is abundant evidence for abnormalities of the serotonin systems in depression and the antidepressants that enhance 5-HT transmission, which in turn improves mood and behavior. However, the available data with respect to rivalry rates in depression are less clear. Therefore, we aimed to explore whether perceptual rivalry was affected by a dysfunctional serotonin system in patients with depression and whether there was a rivalry rate difference between episode and remission states in depression patients. Twenty-eight patients with depression and 30 healthy controls were recruited in the study. We assessed the rivalry rate and the 17-item Hamilton Depression Rating Scale (HAMD) in patients with depression during clinical episode and remission states. The results suggested that alternation rates for patients during episodes were significantly slower than during remission and than in healthy controls. Also, alternation rates for patients during remission were slower than in healthy controls. These results may provide further clues to serotonergic neural systems contributing to the dynamics of perception rivalry and may foster enlightenment regarding the field of binocular rivalry in psychiatric disorders other than bipolar disorder. PMID:26247392

  9. A high precision instrument to measure angular and binocular deviation introduced by aircraft windscreens by using a shadow casting technique

    International Nuclear Information System (INIS)

    Objects viewed through transparent sheets with residual non-parallelism and irregularity appear shifted and distorted. This distortion is measured in terms of angular and binocular deviation of an object viewed through the transparent sheet. The angular and binocular deviations introduced are particularly important in the context of aircraft windscreens and canopies as they can interfere with decision making of pilots especially while landing, leading to accidents. In this work, we have developed an instrument to measure both the angular and binocular deviations introduced by transparent sheets. This instrument is especially useful in the qualification of aircraft windscreens and canopies. It measures the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by the distorted light beam from the transparent test specimen compared to the reference pattern. Accurate quantification of the shift in the pattern is obtained by cross-correlating the reference shadow pattern with the specimen shadow pattern and measuring the location of the correlation peak. The developed instrument is handy to use and computes both angular and binocular deviation with an accuracy of less than ±0.1 mrad (≈0.036 mrad) and has an excellent repeatability with an error of less than 2%.

  10. FPGA Based High Accuracy Synchronous Acquisition Design for Binocular Vision System

    Directory of Open Access Journals (Sweden)

    Lili Lin

    2011-06-01

    Full Text Available This paper proposes a coarse-to-fine two-level synchronous data acquisition and transmission system for binocular stereo vision, which satisfies strict synchronous requirement of stereo vision. Specifically, this synchronization system design contains: coarse level synchronous based on hardware circuit design and the fine level synchronous based on hardware description language (HDL design. The former includes the synchronization design of clock and external trigger. The latter utilizes a multi-level synchronous control strategy from field-level to pixel-level, which consists of field-synchronous acquisition of the two-channel video inputs, two-channel Ping-pong buffers switch control module, and pixel-synchronous bit-splicing and PCI transmission module. The experiments of synchronous acquisition and display demonstrate the high reliability and great performance of this synchronous system.

  11. An Active System for Visually-Guided Reaching in 3D across Binocular Fixations

    Directory of Open Access Journals (Sweden)

    Ester Martinez-Martin

    2014-01-01

    Full Text Available Based on the importance of relative disparity between objects for accurate hand-eye coordination, this paper presents a biological approach inspired by the cortical neural architecture. So, the motor information is coded in egocentric coordinates obtained from the allocentric representation of the space (in terms of disparity generated from the egocentric representation of the visual information (image coordinates. In that way, the different aspects of the visuomotor coordination are integrated: an active vision system, composed of two vergent cameras; a module for the 2D binocular disparity estimation based on a local estimation of phase differences performed through a bank of Gabor filters; and a robotic actuator to perform the corresponding tasks (visually-guided reaching. The approach’s performance is evaluated through experiments on both simulated and real data.

  12. An active system for visually-guided reaching in 3D across binocular fixations.

    Science.gov (United States)

    Martinez-Martin, Ester; del Pobil, Angel P; Chessa, Manuela; Solari, Fabio; Sabatini, Silvio P

    2014-01-01

    Based on the importance of relative disparity between objects for accurate hand-eye coordination, this paper presents a biological approach inspired by the cortical neural architecture. So, the motor information is coded in egocentric coordinates obtained from the allocentric representation of the space (in terms of disparity) generated from the egocentric representation of the visual information (image coordinates). In that way, the different aspects of the visuomotor coordination are integrated: an active vision system, composed of two vergent cameras; a module for the 2D binocular disparity estimation based on a local estimation of phase differences performed through a bank of Gabor filters; and a robotic actuator to perform the corresponding tasks (visually-guided reaching). The approach's performance is evaluated through experiments on both simulated and real data. PMID:24672295

  13. A binocular pupil model for simulation of relative afferent pupil defects and the swinging flashlight test.

    Science.gov (United States)

    Privitera, Claudio M; Stark, Lawrence W

    2006-03-01

    Many important intracranial neural pathways are involved in the control of the two muscles of the human pupil and the observation and analysis of pupil responses to light or other stimuli is of great interest in many clinical procedures. The binocular pupil model presented in this document has a topology encompassing much of the complexity of the pupil system neurophysiology. The dynamic parameters of the model were matched against pupil experiments under multiple conditions. It is employed here to simulate responses to the swinging flashlight test, a procedure which is routinely practiced in ophthalmology to diagnose different degrees of relative afferent pupil defects often a consequence of severe optic nerve diseases or retinal dysfunctions. Other, not light-dependent, pupil stimuli are briefly discussed. PMID:16404612

  14. Perceptual grouping via binocular disparity: The impact of stereoscopic good continuation.

    Science.gov (United States)

    Deas, Lesley M; Wilcox, Laurie M

    2015-08-01

    Stereoscopic contextual effects are widely reported but are generally discussed in terms of 2-D Gestalt grouping principles, e.g., good continuation or closure. We propose that there are disparity-based grouping operations that are separable from 2-D grouping and instead depend on the distribution of binocular disparity information. Two experiments assess the impact of perceptual grouping via good disparity continuation. First, perceived depth magnitude is reduced for a multidot contour with a smooth disparity gradient compared to the end points in isolation. This reduction is eliminated when disparity jitter is introduced to the intermediate dots. Second, observers showed more efficient visual search for the continuous contour versus the discontinuous version. Therefore, when there is spatial support for interpretation of a slanted object, quantitative depth is reduced, but is rapidly detected in visual search. These results reflect the operation of disparity-based grouping, extending the 2-D principle of good continuation into the third dimension. PMID:26275212

  15. Co-Phasing the Large Binocular Telescope:. [Status and Performance of LBTI-PHASECam

    Science.gov (United States)

    Defrere, D.; Hinz, P.; Downey, E.; Ashby, D.; Bailey, V.; Brusa, G.; Christou, J.; Danchi, W. C.; Grenz, P.; Hill, J. M.; Hoffmann, W. F.; Leisenring, J.; Lozi, J.; McMahon, T.; Mennesson, B.; Millan-Gabet, R.; Montoya, M.; Powell, K.; Skemer, A.; Vaitheeswaran, V.; Vaz, A.; Veillet, C.

    2014-01-01

    The Large Binocular Telescope Interferometer is a NASA-funded nulling and imaging instrument designed to coherently combine the two 8.4-m primary mirrors of the LBT for high-sensitivity, high-contrast, and high-resolution infrared imaging (1.5-13 micrometer). PHASECam is LBTI's near-infrared camera used to measure tip-tilt and phase variations between the two AO-corrected apertures and provide high-angular resolution observations. We report on the status of the system and describe its on-sky performance measured during the first semester of 2014. With a spatial resolution equivalent to that of a 22.8-meter telescope and the light-gathering power of single 11.8-meter mirror, the co-phased LBT can be considered to be a forerunner of the next-generation extremely large telescopes (ELT).

  16. Prevalence of Accommodative and Non-Strabismic Binocular Anomalies in a Puerto Rican Pediatric Population

    Directory of Open Access Journals (Sweden)

    Stefania M. Paniccia, OD, MS

    2015-06-01

    Full Text Available Background: There exists a considerable void in the literature of studies that examine the prevalence of non-strabismic binocular and accommodative disorders in the pediatric population of Puerto Rico. The purpose of this retrospective study was to fill this void by performing a comprehensive record review of the pediatric clinical population of the InterAmerican University College of Optometry satellite clinics. Methods: This study was performed using a random selection of 593 existing health records of patients between the ages of 5 and 20 years. Patients had participated in a complete optometric assessment between the years 2004 and 2012. The criteria for selection were the absence of strabismus, amblyopia, nystagmus, vertical deviation, corneal pathology, retinal pathology, lens pathology, or any other parameter outside of population requirements. Results: Statistical analysis was performed using the IBM SPSS program. Results of this study indicate that the most common non-strabismic and accommodative anomalies in the studied population are accommodative insufficiency (39.0%, convergence insufficiency (12.6%, convergence excess (9.1%, and accommodative infacility (7.6%. Conclusions: Accommodative and non-strabismic binocular vision problems are prevalent in the pediatric population of the InterAmerican satellite clinics. This is the first epidemiologic study about the prevalence of these conditions in Puerto Rico. Due to the possibility of these non-strabismic and accommodative anomalies resulting in a reduced quality of life for children and affecting school performance, sports performance, and play activities, an appropriate vision evaluation, diagnosis, and treatment is important. Lastly, further comprehensive studies should be conducted in Puerto Rico using this study as a base for data collection and analysis.

  17. A binocular rivalry study of motion perception in the human brain.

    Science.gov (United States)

    Moutoussis, K; Keliris, G; Kourtzi, Z; Logothetis, N

    2005-08-01

    The relationship between brain activity and conscious visual experience is central to our understanding of the neural mechanisms underlying perception. Binocular rivalry, where monocular stimuli compete for perceptual dominance, has been previously used to dissociate the constant stimulus from the varying percept. We report here fMRI results from humans experiencing binocular rivalry under a dichoptic stimulation paradigm that consisted of two drifting random dot patterns with different motion coherence. Each pattern had also a different color, which both enhanced rivalry and was used for reporting which of the two patterns was visible at each time. As the perception of the subjects alternated between coherent motion and motion noise, we examined the effect that these alternations had on the strength of the MR signal throughout the brain. Our results demonstrate that motion perception is able to modulate the activity of several of the visual areas which are known to be involved in motion processing. More specifically, in addition to area V5 which showed the strongest modulation, a higher activity during the perception of motion than during the perception of noise was also clearly observed in areas V3A and LOC, and less so in area V3. In previous studies, these areas had been selectively activated by motion stimuli but whether their activity reflects motion perception or not remained unclear; here we show that they are involved in motion perception as well. The present findings therefore suggest a lack of a clear distinction between 'processing' versus 'perceptual' areas in the brain, but rather that the areas involved in the processing of a specific visual attribute are also part of the neuronal network that is collectively responsible for its perceptual representation. PMID:15924938

  18. Reinforcement of perceptual inference: reward and punishment alter conscious visual perception during binocular rivalry

    Directory of Open Access Journals (Sweden)

    Gregor eWilbertz

    2014-12-01

    Full Text Available Perception is an inferential process, which becomes immediately evident when sensory information is conflicting or ambiguous and thus allows for more than one perceptual interpretation. Thinking the idea of perception as inference through to the end results in a blurring of boundaries between perception and action selection, as perceptual inference implies the construction of a percept as an active process. Here we therefore wondered whether perception shares a key characteristic of action selection, namely that it is shaped by reinforcement learning. In two behavioral experiments, we used binocular rivalry to examine whether perceptual inference can be influenced by the association of perceptual outcomes with reward or punishment, respectively, in analogy to instrumental conditioning. Binocular rivalry was evoked by two orthogonal grating stimuli presented to the two eyes, resulting in perceptual alternations between the two gratings. Perception was tracked indirectly and objectively through a target detection task, which allowed us to preclude potential reporting biases. Monetary rewards or punishments were given repeatedly during perception of only one of the two rivalling stimuli. We found an increase in dominance durations for the percept associated with reward, relative to the non-rewarded percept. In contrast, punishment led to an increase of the non-punished compared to a relative decrease of the punished percept. Our results show that perception shares key characteristics with action selection, in that it is influenced by reward and punishment in opposite directions, thus narrowing the gap between the conceptually separated domains of perception and action selection. We conclude that perceptual inference is an adaptive process that is shaped by its consequences.

  19. Binocular vision in a virtual world: visual deficits following the wearing of a head-mounted display.

    Science.gov (United States)

    Mon-Williams, M; Wann, J P; Rushton, S

    1993-10-01

    The short-term effects on binocular stability of wearing a conventional head-mounted display (HMD) to explore a virtual reality environment were examined. Twenty adult subjects (aged 19-29 years) wore a commercially available HMD for 10 min while cycling around a computer generated 3-D world. The twin screen presentations were set to suit the average interpupillary distance of our subject population, to mimic the conditions of public access virtual reality systems. Subjects were examined before and after exposure to the HMD and there were clear signs of induced binocular stress for a number of the subjects. The implications of introducing such HMDs into the workplace and entertainment environments are discussed. PMID:8278192

  20. Measuring perceived depth in natural images and study of its relation with monocular and binocular depth cues

    OpenAIRE

    Lebreton, Pierre; Raake, Alexander; Barkowsky, Marcus; Le Callet, Patrick

    2014-01-01

    The perception of depth in images and video sequences is based on different depth cues. Studies have considered depth perception threshold as a function of viewing distance (Cutting & Vishton,1995), the combination of different monocular depth cues and their quantitative relation with binocular depth cues and their different possible type of interactions (Landy,1995). But these studies only consider artificial stimuli and none of them attempts to provide a quantitative contribution of monocular a...

  1. Quantitative visual field assessment of squinting eye under binocular conditions in ten patients with microstrabismus. Preliminary report.

    OpenAIRE

    Joosse, Maurits; Minderhout, H.M. van; Simonsz, Huib; Jong, Paulus

    1994-01-01

    textabstractIntroduction: It is still not exactly known how strabismic patients perceive the surrounding world. It is commonly believed that patients with early onset convergent strabismus and microstrabismus do not suffer from diplopia because of two mechanisms: suppression and anomalous retinal correspondence (ARC). Suppression only occurs under binocular viewing conditions and concerns the central part of the visual field of the strabismic eye. Suppression is associated with a decrease of ...

  2. Measuring perceived depth in natural images and study of its relation with monocular and binocular depth cues

    Science.gov (United States)

    Lebreton, Pierre; Raake, Alexander; Barkowsky, Marcus; Le Callet, Patrick

    2014-03-01

    The perception of depth in images and video sequences is based on different depth cues. Studies have considered depth perception threshold as a function of viewing distance (Cutting and Vishton, 1995), the combination of different monocular depth cues and their quantitative relation with binocular depth cues and their different possible type of interactions (Landy, l995). But these studies only consider artificial stimuli and none of them attempts to provide a quantitative contribution of monocular and binocular depth cues compared to each other in the specific context of natural images. This study targets this particular application case. The evaluation of the strength of different depth cues compared to each other using a carefully designed image database to cover as much as possible different combinations of monocular (linear perspective, texture gradient, relative size and defocus blur) and binocular depth cues. The 200 images were evaluated in two distinct subjective experiments to evaluate separately perceived depth and different monocular depth cues. The methodology and the description of the definition of the different scales will be detailed. The image database (DC3Dimg) is also released for the scientific community.

  3. PEPSI: The high-resolution echelle spectrograph and polarimeter for the Large Binocular Telescope

    CERN Document Server

    Strassmeier, K G; Järvinen, A; Weber, M; Woche, M; Barnes, S I; Bauer, S -M; Beckert, E; Bittner, W; Bredthauer, R; Carroll, T A; Denker, C; Dionies, F; DiVarano, I; Döscher, D; Fechner, T; Feuerstein, D; Granzer, T; Hahn, T; Harnisch, G; Hofmann, A; Lesser, M; Paschke, J; Pankratow, S; Plank, V; Plüschke, D; Popow, E; Sablowski, D; Storm, J

    2015-01-01

    PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2x8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3kx10.3k CCDs with 9-{\\mu}m pixels and peak quantum efficiencies of 96 % record a total of 92 echelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15% at 650 nm, and still 11% and 10% at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of 20th mag in V in the low-resolution mode. The R=...

  4. Precise positioning method for multi-process connecting based on binocular vision

    Science.gov (United States)

    Liu, Wei; Ding, Lichao; Zhao, Kai; Li, Xiao; Wang, Ling; Jia, Zhenyuan

    2016-01-01

    With the rapid development of aviation and aerospace, the demand for metal coating parts such as antenna reflector, eddy-current sensor and signal transmitter, etc. is more and more urgent. Such parts with varied feature dimensions, complex three-dimensional structures, and high geometric accuracy are generally fabricated by the combination of different manufacturing technology. However, it is difficult to ensure the machining precision because of the connection error between different processing methods. Therefore, a precise positioning method is proposed based on binocular micro stereo vision in this paper. Firstly, a novel and efficient camera calibration method for stereoscopic microscope is presented to solve the problems of narrow view field, small depth of focus and too many nonlinear distortions. Secondly, the extraction algorithms for law curve and free curve are given, and the spatial position relationship between the micro vision system and the machining system is determined accurately. Thirdly, a precise positioning system based on micro stereovision is set up and then embedded in a CNC machining experiment platform. Finally, the verification experiment of the positioning accuracy is conducted and the experimental results indicated that the average errors of the proposed method in the X and Y directions are 2.250 μm and 1.777 μm, respectively.

  5. A Real-time Range Finding System with Binocular Stereo Vision

    Directory of Open Access Journals (Sweden)

    Xiao-bo Lai

    2012-05-01

    Full Text Available To acquire range information for mobile robots, a TMS320DM642 DSP‐based range finding system with binocular stereo vision is proposed. Firstly, paired images of the target are captured and a Gaussian filter, as well as improved Sobel kernels, are achieved. Secondly, a feature‐based local stereo matching algorithm is performed so that the space location of the target can be determined. Finally, in order to improve the reliability and robustness of the stereo matching algorithm under complex conditions, the confidence filter and the left‐right consistency filter are investigated to eliminate the mismatching points. In addition, the range finding algorithm is implemented in the DSP/BIOS operating system to gain real‐time control. Experimental results show that the average accuracy of range finding is more than 99% for measuring single‐point distances equal to 120cm in the simple scenario and the algorithm takes about 39ms for ranging a time in a complex scenario. The effectivity, as well as the feasibility, of the proposed range finding system are verified.

  6. Binocular visual tracking and grasping of a moving object with a 3D trajectory predictor

    Directory of Open Access Journals (Sweden)

    J. Fuentes‐Pacheco

    2009-12-01

    Full Text Available This paper presents a binocular eye‐to‐hand visual servoing system that is able to track and grasp a moving object in real time.Linear predictors are employed to estimate the object trajectory in three dimensions and are capable of predicting futurepositions even if the object is temporarily occluded. For its development we have used a CRS T475 manipulator robot with sixdegrees of freedom and two fixed cameras in a stereo pair configuration. The system has a client‐server architecture and iscomposed of two main parts: the vision system and the control system. The vision system uses color detection to extract theobject from the background and a tracking technique based on search windows and object moments. The control system usesthe RobWork library to generate the movement instructions and to send them to a C550 controller by means of the serial port.Experimental results are presented to verify the validity and the efficacy of the proposed visual servoing system.

  7. Large Binocular Telescope Interferometer Adaptive Optics: On-sky performance and lessons learned

    CERN Document Server

    Bailey, Vanessa P; Puglisi, Alfio T; Esposito, Simone; Vaitheeswaran, Vidhya; Skemer, Andrew J; Defrere, Denis; Vaz, Amali; Leisenring, Jarron M

    2014-01-01

    The Large Binocular Telescope Interferometer is a high contrast imager and interferometer that sits at the combined bent Gregorian focus of the LBT's dual 8.4~m apertures. The interferometric science drivers dictate 0.1'' resolution with $10^3-10^4$ contrast at $10~\\mu m$, while the $4~\\mu m$ imaging science drivers require even greater contrasts, but at scales $>$0.2''. In imaging mode, LBTI's Adaptive Optics system is already delivering $4~\\mu m$ contrast of $10^4-10^5$ at $0.3''-0.75''$ in good conditions. Even in poor seeing, it can deliver up to 90\\% Strehl Ratio at this wavelength. However, the performance could be further improved by mitigating Non-Common Path Aberrations. Any NCPA remedy must be feasible using only the current hardware: the science camera, the wavefront sensor, and the adaptive secondary mirror. In preliminary testing, we have implemented an ``eye doctor'' grid search approach for astigmatism and trefoil, achieving 5\\% improvement in Strehl Ratio at $4~\\mu m$, with future plans to tes...

  8. Effects of quantum noise and binocular summation on dose requirements in stereoradiography

    International Nuclear Information System (INIS)

    In the case of a quantum-noise limited detector, signal detection theory suggests that stereoradiographic images can be acquired with one half of the per-image dose needed for a standard radiographic projection, as information from the two stereo images can be combined. Previously, film-screen stereoradiography has been performed using the same per-image dose as in projection radiography, i.e., doubling the total dose. In this paper, the assumption of a possible decrease in dose for stereoradiography was tested by a series of contrast-detail experiments, using phantom images acquired over a range of exposures. The number of visible details, the effective reduction of the dose, and the effective decrease in the threshold signal-to-noise ratio were determined using human observers under several display and viewing conditions. These results were averaged over five observers and compared with multiple readings by a single observer and with the results of an additional observer with limited stereoscopic acuity. Experimental results show that the total dose needed to produce a stereoradiographic image pair is approximately 1.1 times the dose needed for a single projection in standard radiography, indicating that under these conditions the human visual system demonstrates almost ideal binocular summation

  9. Three-dimensional infrared imaging method based on binocular stereo vision

    Science.gov (United States)

    Sun, Junhua; Ma, Haining; Zeng, Debing

    2015-10-01

    The infrared imaging technique is characterized as high-precision and noncontact and provides the temperature information of the object, leading to its broad application in civil and military fields. Currently, the research on infrared thermography is mainly focused on two-dimensional images, lacking the information in depth orientation. To extend the range of application and provide spatial information, a three-dimensional (3-D) infrared imaging system based on binocular stereo vision is presented. The system is composed of two visible-light cameras, an infrared camera, and a digital projector. The proposed system fuses the metric information and the infrared information to acquire the 3-D surface temperature distribution by combining the 3-D reconstruction technique with infrared thermography. The registration of the metric information and the infrared image is accomplished according to the properties of three-view geometry. Experiments have been undertaken with a storage box, a rudder model, and a person's stretching arm, respectively, and the results demonstrated the good performance of the proposed method.

  10. Nulling Data Reduction and On-Sky Performance of the Large Binocular Telescope Interferometer

    CERN Document Server

    Defrère, D; Mennesson, B; Hoffmann, W F; Millan-Gabet, R; Skemer, A J; Bailey, V; Danchi, W C; Downey, E C; Durney, O; Grenz, P; Hill, J M; McMahon, T J; Montoya, M; Spalding, E; Vaz, A; Absil, O; Arbo, P; Bailey, H; Brusa, G; Bryden, G; Esposito, S; Gaspar, A; Haniff, C A; Kennedy, G M; Leisenring, J M; Marion, L; Nowak, M; Pinna, E; Powell, K; Puglisi, A; Rieke, G; Roberge, A; Serabyn, E; Sosa, R; Stapeldfeldt, K; Su, K; Weinberger, A J; Wyatt, M C

    2016-01-01

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high-angular resolution and high-contrast infrared imaging (1.5-13 microns). In this paper, we focus on the mid-infrared (8-13 microns) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in March 2015. With an interferometric baseline of 14.4 meters, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exoEarth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in February 2015 a calibrated null accuracy of 0.05% over a three-hour long observing sequence on the bright nearby A3V star beta Leo. This is equivalent to an exozodiacal dis...

  11. Eyepiece-type full-color electro-holographic display for binocular vision

    Science.gov (United States)

    Yoneyama, Takuo; Yang, Chanyoung; Sakamoto, Yuji; Okuyama, Fumio

    2013-03-01

    Head-mounted type 3-D displays are expected to be useful with Augmented Reality techniques to provide visual information. However, because these displays use the stereoscopic method to provide 3-D vision, observers tend to experience eye discomfort when viewing 3-D images due to the disparity between accommodation and convergence. Electro-holography is a rival technique that displays holograms on electrical devices such as a spatial light modulator and enables observers to view ideal 3-D images in comfort for many hours. In the current study, we applied the holography technique to an eyepiece-type display in order to solve the disparity problem. Our system can represent 3-D images at arbitrary depths and displays large reconstructed images by using a Fourier transform optical system. We also adopted the time division color method to reconstruct full-color images. In computer generated holography, holograms for each color are calculated considering with the distance between their wavelength. In this paper, we describe our calculation algorithm and report the fabrication of an eyepiecetype full color electro-holographic display for binocular vision. To confirm the effectiveness of the proposed system, the reconstructed images were evaluated both objectively and subjectively. Results of experiments show that reconstructed full-color images are located at the correct depth.

  12. A wearable infrared video pupillography with multi-stimulation of consistent illumination for binocular pupil response

    Science.gov (United States)

    Mang, Ou-Yang; Ko, Mei Lan; Tsai, Yi-Chun; Chiou, Jin-Chern; Huang, Ting-Wei

    2016-03-01

    The pupil response to light can reflect various kinds of diseases which are related to physiological health. Pupillary abnormalities may be influenced on people by autonomic neuropathy, glaucoma, diabetes, genetic diseases, and high myopia. In the early stage of neuropathy, it is often asymptomatic and difficulty detectable by ophthalmologists. In addition, the position of injured nerve can lead to unsynchronized pupil response for human eyes. In our study, we design the pupilometer to measure the binocular pupil response simultaneously. It uses the different wavelength of LEDs such as white, red, green and blue light to stimulate the pupil and record the process. Therefore, the pupilometer mainly contains two systems. One is the image acquisition system, it use the two cameras modules with the same external triggered signal to capture the images of the pupil simultaneously. The other one is the illumination system. It use the boost converter ICs and LED driver ICs to supply the constant current for LED to maintain the consistent luminance in each experiments for reduced experimental error. Furthermore, the four infrared LEDs are arranged nearby the stimulating LEDs to illuminate eyes and increase contrast of image for image processing. In our design, we success to implement the function of synchronized image acquisition with the sample speed in 30 fps and the stable illumination system for precise measurement of experiment.

  13. Investigating binocular summation in human vision using complementary fused external noise

    Science.gov (United States)

    Howell, Christopher L.; Olson, Jeffrey T.

    2016-05-01

    The impact noise has on the processing of visual information at various stages within the human visual system (HVS) is still an open research area. To gain additional insight, twelve experiments were administered to human observers using sine wave targets to determine their contrast thresholds. A single frame of additive white Gaussian noise (AWGN) and its complement were used to investigate the effect of noise on the summation of visual information within the HVS. A standard contrast threshold experiment served as the baseline for comparisons. In the standard experiment, a range of sine wave targets are shown to the observers and their ability to detect the targets at varying contrast levels were recorded. The remaining experiments added some form of noise (noise image or its complement) and/or an additional sine wave target separated between one to three octaves to the test target. All of these experiments were tested using either a single monitor for viewing the targets or with a dual monitor presentation method for comparison. In the dual monitor experiments, a ninety degree mirror was used to direct each target to a different eye, allowing for the information to be fused binocularly. The experiments in this study present different approaches for delivering external noise to the HVS, and should allow for an improved understanding regarding how noise enters the HVS and what impact noise has on the processing of visual information.

  14. The effects of noise on binocular rivalry waves: a stochastic neural field model

    International Nuclear Information System (INIS)

    We analyze the effects of extrinsic noise on traveling waves of visual perception in a competitive neural field model of binocular rivalry. The model consists of two one-dimensional excitatory neural fields, whose activity variables represent the responses to left-eye and right-eye stimuli, respectively. The two networks mutually inhibit each other, and slow adaptation is incorporated into the model by taking the network connections to exhibit synaptic depression. We first show how, in the absence of any noise, the system supports a propagating composite wave consisting of an invading activity front in one network co-moving with a retreating front in the other network. Using a separation of time scales and perturbation methods previously developed for stochastic reaction–diffusion equations, we then show how extrinsic noise in the activity variables leads to a diffusive-like displacement (wandering) of the composite wave from its uniformly translating position at long time scales, and fluctuations in the wave profile around its instantaneous position at short time scales. We use our analysis to calculate the first-passage-time distribution for a stochastic rivalry wave to travel a fixed distance, which we find to be given by an inverse Gaussian. Finally, we investigate the effects of noise in the depression variables, which under an adiabatic approximation lead to quenched disorder in the neural fields during propagation of a wave. (paper)

  15. Structural Parameters Calibration for Binocular Stereo Vision Sensors Using a Double-Sphere Target.

    Science.gov (United States)

    Wei, Zhenzhong; Zhao, Kai

    2016-01-01

    Structural parameter calibration for the binocular stereo vision sensor (BSVS) is an important guarantee for high-precision measurements. We propose a method to calibrate the structural parameters of BSVS based on a double-sphere target. The target, consisting of two identical spheres with a known fixed distance, is freely placed in different positions and orientations. Any three non-collinear sphere centres determine a spatial plane whose normal vector under the two camera-coordinate-frames is obtained by means of an intermediate parallel plane calculated by the image points of sphere centres and the depth-scale factors. Hence, the rotation matrix R is solved. The translation vector T is determined using a linear method derived from the epipolar geometry. Furthermore, R and T are refined by nonlinear optimization. We also provide theoretical analysis on the error propagation related to the positional deviation of the sphere image and an approach to mitigate its effect. Computer simulations are conducted to test the performance of the proposed method with respect to the image noise level, target placement times and the depth-scale factor. Experimental results on real data show that the accuracy of measurement is higher than 0.9‰, with a distance of 800 mm and a view field of 250 × 200 mm². PMID:27420063

  16. The effects of noise on binocular rivalry waves: a stochastic neural field model

    KAUST Repository

    Webber, Matthew A

    2013-03-12

    We analyze the effects of extrinsic noise on traveling waves of visual perception in a competitive neural field model of binocular rivalry. The model consists of two one-dimensional excitatory neural fields, whose activity variables represent the responses to left-eye and right-eye stimuli, respectively. The two networks mutually inhibit each other, and slow adaptation is incorporated into the model by taking the network connections to exhibit synaptic depression. We first show how, in the absence of any noise, the system supports a propagating composite wave consisting of an invading activity front in one network co-moving with a retreating front in the other network. Using a separation of time scales and perturbation methods previously developed for stochastic reaction-diffusion equations, we then show how extrinsic noise in the activity variables leads to a diffusive-like displacement (wandering) of the composite wave from its uniformly translating position at long time scales, and fluctuations in the wave profile around its instantaneous position at short time scales. We use our analysis to calculate the first-passage-time distribution for a stochastic rivalry wave to travel a fixed distance, which we find to be given by an inverse Gaussian. Finally, we investigate the effects of noise in the depression variables, which under an adiabatic approximation lead to quenched disorder in the neural fields during propagation of a wave. © 2013 IOP Publishing Ltd and SISSA Medialab srl.

  17. Why is binocular rivalry uncommon? Discrepant monocular images in the real world

    Directory of Open Access Journals (Sweden)

    Derek Henry Arnold

    2011-10-01

    Full Text Available When different images project to corresponding points in the two eyes they can instigate a phenomenon called binocular rivalry (BR, wherein each image seems to intermittently disappear such that only one of the two images is seen at a time. Cautious readers may have noted an important caveat in the opening sentence – this situation can instigate BR, but usually it doesn’t. Unmatched monocular images are frequently encountered in daily life due to either differential occlusions of the two eyes or because of selective obstructions of just one eye, but this does not tend to induce BR. Here I will explore the reasons for this and discuss implications for BR in general. It will be argued that BR is resolved in favour of the instantaneously stronger neural signal, and that this process is driven by an adaptation that enhances the visibility of distant fixated objects over that of more proximate obstructions of an eye. Accordingly, BR would reflect the dynamics of an inherently visual operation that usually deals with real-world constraints.

  18. Hearing (Rivaling Lips and Seeing Voices: How Audiovisual Interactions Modulate Perceptual Stabilization in Binocular Rivalry

    Directory of Open Access Journals (Sweden)

    Manuel eVidal

    2014-09-01

    Full Text Available In binocular rivalry (BR, sensory input remains the same yet subjective experience fluctuates irremediably between two mutually exclusive representations. We investigated the perceptual stabilization effect of an additional sound on the BR dynamics using speech stimuli known to involve robust audiovisual (AV interactions at several cortical levels. Subjects sensitive to the McGurk effect were presented looping videos of rivaling faces uttering /aba/ and /aga/ respectively, while synchronously hearing the voice /aba/. They reported continuously the dominant percept, either observing passively or trying actively to promote one of the faces. The few studies that investigated the influence of information from an external modality on perceptual competition reported results that seem at first sight inconsistent. Since these differences could stem from how well the modalities matched, we addressed this by comparing two levels of AV congruence: real (/aba/ viseme vs. illusory (/aga/ viseme producing the /ada/ McGurk fusion. First, adding the voice /aba/ stabilized both real and illusory congruent lips percept. Second, real congruence of the added voice improved volitional control whereas illusory congruence did not, suggesting a graded contribution to the top-down sensitivity control of selective attention. In conclusion, a congruent sound enhanced considerably attentional control over the perceptual outcome selection; however, differences between passive stabilization and active control according to AV congruency suggest these are governed by two distinct mechanisms. Based on existing theoretical models of BR, selective attention and AV interaction in speech perception, we provide a general interpretation of our findings.

  19. Differences of accommodative responses between two eyes under binocular viewing condition mediated by polarizing glasses

    Directory of Open Access Journals (Sweden)

    Rui-Qing Wang

    2016-04-01

    Full Text Available AIM:To study the differences of accommodative responses between the two eyes under 3 different polarized viewing conditions. METHODS:Fifteen volunteers with emmetrope were recruited into this study(aged 18~38, 6 males and 9 females. Three different viewing conditions were set up by using polarizing glasses and liquid crystal display:(1right eye could see the visual target on the screen, but left eye cannot see it;(2left eye could see the visual target on the screen, but right eye cannot see it;(3both eyes could see the target. Accommodative responses were measured by infrared auto-refractor when fixating at the target at 5, 2, 1, 0.5 and 0.33m under the above 3 viewing conditions. The differences of accommodative responses under different viewing conditions were compared by using variance analysis of repeated measuring and t test. RESULTS:Significant differences of accommodative responses between the two eyes were found under condition(1and(2at all the fixating distance. The accommodative responses in used eyes which can see the visual target were higher than in non-used eyes which cannot see the visual target(PP>0.05. CONCLUSION:Ciliary muscles in the used eyes were more relatively tonic than non-used eyes under binocular open viewing condition. The imbalance of accommodative responses between two eyes may be one of the risk factors resulting into the occurrence of myopia.

  20. Large Binocular Telescope Adaptive Optics System: New achievements and perspectives in adaptive optics

    CERN Document Server

    Esposito, Simone; Pinna, Enrico; Puglisi, Alfio; Quirós-Pacheco, Fernando; Arcidiacono, Carmelo; Xompero, Marco; Briguglio, Runa; Agapito, Guido; Busoni, Lorenzo; Fini, Luca; Argomedo, Javier; Gherardi, Alessandro; Brusa, Guido; Miller, Douglas; Guerra, Juan Carlos; Stefanini, Paolo; Salinari, Piero; 10.1117/12.898641

    2012-01-01

    The Large Binocular Telescope (LBT) is a unique telescope featuring two co-mounted optical trains with 8.4m primary mirrors. The telescope Adaptive Optics (AO) system uses two innovative key components, namely an adaptive secondary mirror with 672 actuators and a high-order pyramid wave-front sensor. During the on-sky commissioning such a system reached performances never achieved before on large ground-based optical telescopes. Images with 40mas resolution and Strehl Ratios higher than 80% have been acquired in H band (1.6 micron). Such images showed a contrast as high as 10e-4. Based on these results, we compare the performances offered by a Natural Guide Star (NGS) system upgraded with the state-of-the-art technology and those delivered by existing Laser Guide Star (LGS) systems. The comparison, in terms of sky coverage and performances, suggests rethinking the current role ascribed to NGS and LGS in the next generation of AO systems for the 8-10 meter class telescopes and Extremely Large Telescopes (ELTs)...

  1. Calibração binocular com gabaritos 1D sem restrição demovimentos Binocular calibration with 1D parttern without movements restriction

    Directory of Open Access Journals (Sweden)

    José Alexandre de França

    2011-06-01

    Full Text Available Na visão computacional, a calibração de câmeras é um processo necessário quando deseja-se recuperar informações como, por exemplo, ângulos e distâncias. O presente trabalho trata do problema de calibração de câmeras com gabaritos de uma única dimensão. Atualmente, tal problema só tem solução se forem impostas restrições ao movimento do gabarito ou se alguns parâmetros das câmeras já sejam previamente conhecidos. Contudo, demonstra-se que uma abordagem diferente pode ser aplicada se, ao invés de uma única câmera, um conjunto binocular for considerado. Nesse caso, a calibração é possível com um gabarito 1D que realiza um deslocamento desconhecido e sem restrições, mesmo sem nenhuma informação prévia a respeito das câmeras. Tal método baseia-se na estimação de uma transformação que, após a estimação da matriz fundamental do sistema, permite atualizar uma calibração projetiva para uma calibração euclidiana. Experimentos em imagens reais e sintéticas validam o novo método e mostram que a sua exatidão é comparável a de outros métodos clássicos de calibração, já bem conhecidos na literatura.In computer vision, the camera calibration is a process needed when the recovery of some information, such as angles and distances, is desired. The present work deals with the problem of camera calibration using one-dimensional patterns. Nowadays, this problem only has a solution if some restrictions to the pattern's movement are imposed or if some angles of the cameras are known in advance. However, a different approach can be applied if, instead of only one camera, a stereo system is considered. In that case, the calibration is possible with a one-dimensional pattern that executes an unknown and unrestricted movement, even without any previous information concerning the cameras. Such method is based on the estimation of a transform which, after the estimation of the system's fundamental matrix, allows

  2. Binocular vision and abnormal head posture in children when watching television

    Science.gov (United States)

    Zhang, Di; Zhang, Wei-Hong; Dai, Shu-Zhen; Peng, Hai-Ying; Wang, Li-Ya

    2016-01-01

    AIM To determine the association between the binocular vision and an abnormal head posture (AHP) when watching television (TV) in children 7-14y of age. METHODS Fifty normal children in the normal group and 52 children with an AHP when watching TV in the AHP group were tested for spherical equivalents, far and near fusional convergence (FC) and fusional divergence (FD) amplitudes, near point of convergence, far and near heterophoria, accommodative convergence/ accommodation ratio and stereoacuity. The values of these tests were compared between the two groups. The independent t test was applied at a confidence level of 95%. RESULTS The far and near FC amplitudes and far FD amplitudes were lower in the AHP group (the far FC amplitudes: break point 13.6±5.4Δ, recovery point 8.7±5.4Δ. The near FC amplitudes: break point 14.5±7.3Δ, recovery point 10.3±5.1Δ. The far FD amplitudes: break point 3.9±2.7Δ, recovery point 2.6±2.3Δ) compared with those in the normal group (the far FC amplitudes: break point 19.1±6.2Δ, recovery point 12.4±4.5Δ. The near FC amplitudes: break point 22.3±8.0Δ, recovery point 16.1±5.7Δ. The far FD amplitudes: break point 7.0±2.1Δ, recovery point 4.6±1.9Δ). Other tests presented no statistically significant differences. CONCLUSION An association between the reduced FC and FD amplitudes and the AHP in children when watching TV is proposed in the study. This kind of AHP is considered to be an anomalous manifestation which appears in a part of puerile patients of fusional vergence dysfunction. PMID:27275434

  3. Computer-enhanced stereoscopic vision in a head-mounted operating binocular

    International Nuclear Information System (INIS)

    Based on the Varioscope, a commercially available head-mounted operating binocular, we have developed the Varioscope AR, a see through head-mounted display (HMD) for augmented reality visualization that seamlessly fits into the infrastructure of a surgical navigation system. We have assessed the extent to which stereoscopic visualization improves target localization in computer-aided surgery in a phantom study. In order to quantify the depth perception of a user aiming at a given target, we have designed a phantom simulating typical clinical situations in skull base surgery. Sixteen steel spheres were fixed at the base of a bony skull, and several typical craniotomies were applied. After having taken CT scans, the skull was filled with opaque jelly in order to simulate brain tissue. The positions of the spheres were registered using VISIT, a system for computer-aided surgical navigation. Then attempts were made to locate the steel spheres with a bayonet probe through the craniotomies using VISIT and the Varioscope AR as a stereoscopic display device. Localization of targets 4 mm in diameter using stereoscopic vision and additional visual cues indicating target proximity had a success rate (defined as a first-trial hit rate) of 87.5%. Using monoscopic vision and target proximity indication, the success rate was found to be 66.6%. Omission of visual hints on reaching a target yielded a success rate of 79.2% in the stereo case and 56.25% with monoscopic vision. Time requirements for localizing all 16 targets ranged from 7.5 min (stereo, with proximity cues) to 10 min (mono, without proximity cues). Navigation error is primarily governed by the accuracy of registration in the navigation system, whereas the HMD does not appear to influence localization significantly. We conclude that stereo vision is a valuable tool in augmented reality guided interventions. (note)

  4. Multi-laser-guided adaptive optics for the Large Binocular Telescope

    Science.gov (United States)

    Lloyd-Hart, M.; Angel, R.; Green, R.; Stalcup, T.; Milton, N. M.; Powell, K.

    2007-09-01

    We describe the conceptual design of an advanced laser guide star facility (LGSF) for the Large Binocular Telescope (LBT), to be built in collaboration with the LBT's international partners. The highest priority goal for the facility is the correction of ground-layer turbulence, providing partial seeing compensation in the near IR bands over a 4' field. In the H band, GLAO is projected to improve the median seeing from 0.55" to 0.2". The new facility will build on the LBT's natural guide star AO system, integrated into the telescope with correction by adaptive secondary mirrors, and will draw on Arizona's experience in the construction of the first multi-laser adaptive optics (AO) system at the 6.5 m MMT. The LGSF will use four Rayleigh beacons at 532 nm, projected to an altitude of 25 km, on each of the two 8.4 m component telescopes. Initial use of the system for ground layer correction will deliver image quality well matched to the LBT's two LUCIFER near IR instruments. They will be used for direct imaging over a 4'×4' field and will offer a unique capability in high resolution multi-object spectroscopy. The LGSF is designed to include long-term upgrade paths. Coherent imaging at the combined focus of the two apertures will be exploited by the LBT Interferometer in the thermal IR. Using the same launch optics, an axial sodium or Rayleigh beacon can be added to each constellation, for tomographic wavefront reconstruction and diffraction limited imaging over the usual isoplanatic patch. In the longer term, a second DM conjugated to high altitude is foreseen for the LBT's LINC-NIRVANA instrument, which would extend the coherent diffraction-limited field to an arcminute in diameter with multi-conjugate AO.

  5. Cortical microcircuit dynamics mediating Binocular Rivalry: The role of adaptation in inhibition

    Directory of Open Access Journals (Sweden)

    Panagiota eTheodoni

    2011-11-01

    Full Text Available Perceptual bistability arises when two conflicting interpretations of an ambiguous stimulus or images in binocular rivalry (BR compete for perceptual dominance. From a computational point of view competition models based on cross-inhibition and adaptation have shown that noise is a crucial force for rivalry and operates in balance with adaptation in order to explain the observed alternations in perception. In particular, noise-driven transitions and adaptation-driven oscillations define two dynamical regimes and the system operates near its boundary. In order to gain insights into the microcircuit dynamics mediating spontaneous perceptual alternations we used a reduced recurrent attractor-based biophysically realistic spiking network well known for working memory, attention and decision-making, where a spike-frequency adaptation mechanism is implemented to account for perceptual bistability. We, thus, derived a consistently reduced four-variable population rate model using mean-field techniques and tested it on BR data collected from human subjects. Our model accounts for experimental data parameters such as time dominance, coefficient of variation and gamma distribution. In addition, we show that our model also operates on the boundary between noise and adaptation and agrees with Levelt’s second revised and fourth propositions. These results show for the first time that a consistent reduction of a biophysically realistic spiking network of integrate and fire neurons with spike frequency adaptation could account for BR. Moreover, we demonstrate that BR can be explained only through the dynamics of the competing neuronal pools, without taking into account the adaptation of inhibitory interneurons..However, adaptation of interneurons affects the optimal parametric space of the system, by decreasing the overall adaptation necessary for the bifurcation to occur.

  6. Near Point of Convergence Break for Different Age Groups in Turkish Population with Normal Binocular Vision: Normative Data

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    Nihat Sayın

    2013-12-01

    Full Text Available Purpose: The purpose of this study was to evaluate the near point of convergence break in Turkish population with normal binocular vision and to obtain the normative data for the near point of convergence break in different age groups. Such database has not been previously reported. Material and Method: In this prospective study, 329 subjects with normal binocular vision (age range, 3-72 years were evaluated. The near point of convergence break was measured 4 times repeatedly with an accommodative target. Mean values of near point of convergence break were provided for these age groups (≤10, 11-20, 21-30, 31-40, 41-50, 51-60, and >60 years old. A statistical comparison (one-way ANOVA and post-hoc test of these values between age groups was performed. A correlation between the near point of convergence break and age was evaluated by Pearson’s correlation test. Results: The mean value for near point of convergence break was 2.46±1.88 (0.5-14 cm. Specifically, 95% of measurements in all subjects were 60 year-old age groups in the near point of convergence break values (p=0.0001, p=0.0001, p=0.006, p=0.001, p= 0.004. A mild positive correlation was observed between the increase in near point of convergence break and increase of age (r=0.355 (p<0.001. Discussion: The values derived from a relatively large study population to establish a normative database for the near point of convergence break in the Turkish population with normal binocular vision are in relevance with age. This database has not been previously reported. (Turk J Ophthalmol 2013; 43: 402-6

  7. Metabolic changes in the visual cortex of binocular blindness macaque monkeys: a proton magnetic resonance spectroscopy study.

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    Lingjie Wu

    Full Text Available PURPOSE: To evaluate proton magnetic resonance spectroscopy ((1H-MRS in a study of cross-modal plasticity in the visual cortex of binocular blindness macaque monkeys. MATERIALS AND METHODS: Four healthy neonatal macaque monkeys were randomly divided into 2 groups, with 2 in each group. Optic nerve transection was performed in both monkeys in the experimental group (group B to obtain binocular blindness. Two healthy macaque monkeys served as a control group (group A. After sixteen months post-procedure, (1H-MRS was performed in the visual cortex of all monkeys. We compared the peak areas of NAA, Cr, Cho, Glx and Ins and the ratios of NAA/Cr, Cho/Cr, Glx/Cr and Ins/Cr of each monkey in group B with group A. RESULTS: The peak area of NAA and the NAA/Cr ratio in the visual cortex of monkey 4 in group B were found to be dramatically decreased, the peak area of NAA slightly decreased and the NAA/Cr ratio clearly decreased in visual cortex of monkey 3 in group B than those in group A. The peak area of Ins and the Ins/Cr ratio in the visual cortex of monkey 4 in group B slightly increased. The peak area of Cho and the Cho/Cr ratio in the visual cortex of all monkeys in group B dramatically increased compared with group A. The peak area of Glx in the visual cortex of all monkeys in group B slightly increased compared with group A. CONCLUSIONS: (1H-MRS could detect biochemical and metabolic changes in the visual cortex and therefore this technique can be used to provide valuable information for investigating the mechanisms of cross-modal plasticity of binocular blindness in a macaque monkey model.

  8. Infrared Narrowband Tomography of the Local Starburst NGC 1569 with the Large Binocular Telescope/LUCIFER

    Science.gov (United States)

    Pasquali, A.; Bik, A.; Zibetti, S.; Ageorges, N.; Seifert, W.; Brandner, W.; Rix, H.-W.; Jütte, M.; Knierim, V.; Buschkamp, P.; Feiz, C.; Gemperlein, H.; Germeroth, A.; Hofmann, R.; Laun, W.; Lederer, R.; Lehmitz, M.; Lenzen, R.; Mall, U.; Mandel, H.; Müller, P.; Naranjo, V.; Polsterer, K.; Quirrenbach, A.; Schäffner, L.; Storz, C.; Weiser, P.

    2011-04-01

    We used the near-IR imager/spectrograph LUCIFER mounted on the Large Binocular Telescope to image, with subarcsecond seeing, the local dwarf starburst NGC 1569 in the JHK bands and He I 1.08 μm, [Fe II] 1.64 μm, and Brγ narrowband filters. We obtained high-quality spatial maps of He I 1.08 μm, [Fe II] 1.64 μm, and Brγ emission across the galaxy, and used them together with Hubble Space Telescope/Advanced Camera for Surveys images of NGC 1569 in the Hα filter to derive the two-dimensional spatial map of the dust extinction and surface star formation rate (SFR) density. We show that dust extinction (as derived from the Hα/Brγ flux ratio) is rather patchy and, on average, higher in the northwest (NW) portion of the galaxy (E g(B - V) ~= 0.71 mag) than in the southeast (E g(B - V) ~= 0.57 mag). Similarly, the surface density of SFR (computed from either the dereddened Hα or dereddened Brγ image) peaks in the NW region of NGC 1569, reaching a value of about 4 × 10-6 M sun yr-1 pc-2. The total SFR as estimated from the integrated, dereddened Hα (or, alternatively, Brγ) luminosity is about 0.4 M sun yr-1, and the total supernova rate from the integrated, dereddened [Fe II] 1.64 μm luminosity is about 0.005 yr-1 (assuming a distance of 3.36 Mpc). The azimuthally averaged [Fe II] 1.64 μm/Brγ flux ratio is larger at the edges of the central, gas-deficient cavities (encompassing the superstar clusters A and B) and in the galaxy outskirts. If we interpret this line ratio as the ratio between the average past star formation (as traced by supernovae) and ongoing activity (represented by OB stars able to ionize the interstellar medium), it would then indicate that star formation has been quenched within the central cavities and lately triggered in a ring around them. The number of ionizing hydrogen and helium photons as computed from the integrated, dereddened Hα and He I 1.08 μm luminosities suggests that the latest burst of star formation occurred about 4 Myr

  9. INFRARED NARROWBAND TOMOGRAPHY OF THE LOCAL STARBURST NGC 1569 WITH THE LARGE BINOCULAR TELESCOPE/LUCIFER

    International Nuclear Information System (INIS)

    We used the near-IR imager/spectrograph LUCIFER mounted on the Large Binocular Telescope to image, with subarcsecond seeing, the local dwarf starburst NGC 1569 in the JHK bands and He I 1.08 μm, [Fe II] 1.64 μm, and Brγ narrowband filters. We obtained high-quality spatial maps of He I 1.08 μm, [Fe II] 1.64 μm, and Brγ emission across the galaxy, and used them together with Hubble Space Telescope/Advanced Camera for Surveys images of NGC 1569 in the Hα filter to derive the two-dimensional spatial map of the dust extinction and surface star formation rate (SFR) density. We show that dust extinction (as derived from the Hα/Brγ flux ratio) is rather patchy and, on average, higher in the northwest (NW) portion of the galaxy (Eg(B - V) ≅ 0.71 mag) than in the southeast (Eg(B - V) ≅ 0.57 mag). Similarly, the surface density of SFR (computed from either the dereddened Hα or dereddened Brγ image) peaks in the NW region of NGC 1569, reaching a value of about 4 x 10-6 Msun yr-1 pc-2. The total SFR as estimated from the integrated, dereddened Hα (or, alternatively, Brγ) luminosity is about 0.4 Msun yr-1, and the total supernova rate from the integrated, dereddened [Fe II] 1.64 μm luminosity is about 0.005 yr-1 (assuming a distance of 3.36 Mpc). The azimuthally averaged [Fe II] 1.64 μm/Brγ flux ratio is larger at the edges of the central, gas-deficient cavities (encompassing the superstar clusters A and B) and in the galaxy outskirts. If we interpret this line ratio as the ratio between the average past star formation (as traced by supernovae) and ongoing activity (represented by OB stars able to ionize the interstellar medium), it would then indicate that star formation has been quenched within the central cavities and lately triggered in a ring around them. The number of ionizing hydrogen and helium photons as computed from the integrated, dereddened Hα and He I 1.08 μm luminosities suggests that the latest burst of star formation occurred about 4 Myr

  10. Altered GABAergic markers, increased binocularity and reduced plasticity in the visual cortex of Engrailed-2 knockout mice

    Directory of Open Access Journals (Sweden)

    Manuela Allegra

    2014-06-01

    Here we studied GABAergic markers and cortical function in En2-/- mice, by exploiting the well-known anatomical and functional features of the mouse visual system. En2 is expressed in the visual cortex at postnatal day 30 and during adulthood. When compared to age-matched En2+/+ controls, En2-/- mice showed an increased number of parvalbumin (PV+, somatostatin (SOM+ and neuropeptide Y (NPY+ positive interneurons in the visual cortex at P30, and a decreased number of SOM+ and NPY+ interneurons in the adult. At both ages, the differences in distinct interneuron populations observed between En2+/+ and En2-/- mice were layer-specific. Adult En2-/- mice displayed a normal eye-specific segregation in the retino-geniculate pathway, and in vivo electrophysiological recordings showed a normal development of basic functional properties (acuity, response latency, receptive field size of the En2-/- primary visual cortex. However, a significant increase of binocularity was found in P30 and adult En2-/- mice, as compared to age-matched controls. Differently from what observed in En2+/+ mice, the En2-/- primary visual cortex did not respond to a brief monocular deprivation performed between P26 and P29, during the so-called “critical period”. These data suggest that altered GABAergic circuits impact baseline binocularity and plasticity in En2-/- mice, while leaving other visual functional properties unaffected.

  11. Functional MRI activity in the thalamus and occipital cortex of anesthetized dogs induced by monocular and binocular stimulation.

    Science.gov (United States)

    Willis, C K; Quinn, R P; McDonell, W M; Gati, J; Partlow, G; Vilis, T

    2001-07-01

    The neuroanatomy of the mammalian visual system has received considerable attention through electrophysiological study of cats and non-human primates, and through neuroimaging of humans. Canine neuroanatomy, however, has received much less attention, limiting our understanding of canine vision and visual pathways. As an early step in applying blood oxygenation level dependant (BOLD) functional magnetic resonance imaging (fMRI) for veterinary use, we compared visual activity in the thalamus and occipital cortex of anesthetized dogs presented with binocular and monocular visual stimuli. Activity in the left and right thalamus and occipital cortex during monocular stimulation was also compared. Six beagles were presented with a vertical grating visual stimulus and scanned at 4 Tesla. Each dog was scanned twice under each of 3 anesthetic protocols (isoflurane, propofol, and fentanyl/midazolam). We found: 1) significant BOLD activation in the lateral geniculate nucleus (LGN) of the thalamus and the occipital cortex; 2) a significantly larger area of activation in the LGN during monocular stimulation than during binocular stimulation; and 3) that activity in the hemisphere contralateral to the stimulus was not significantly greater than that ipsilateral to it. PMID:11480525

  12. 基于 OpenCV 的双目摄像机标定技术研究%Binocular Camera Calibration Technique Based on OpenCV

    Institute of Scientific and Technical Information of China (English)

    王长元; 邢世蒙

    2014-01-01

    摄像机标定技术作为双目立体视觉领域的一个基础性研究课题,具有很大的理论研究价值和实际应用价值。论文围绕双目立体视觉中的双目摄像机标定技术,分析基于OpenCV的双目摄像机标定的方法。基于OpenCV的双目摄像机标定比传统的定标技术更为灵活,并且具有不错的定标精度。%As a foundational research in the field of binocular stereo vision ,camera calibration technique has great theo‐retical value and practical value .This paper focuses on the binocular stereo vision camera calibration technique to analyze the binocular camera calibration method based on OpenCV .OpenCV camera calibration based on binocular is more flexible than traditional scaling techniques ,and has a good calibration accuracy .

  13. 基于 OpenCV 的双目摄像机标定技术研究%Binocular Camera Calibration Technique Based on OpenCV

    Institute of Scientific and Technical Information of China (English)

    王长元; 邢世蒙

    2014-01-01

    As a foundational research in the field of binocular stereo vision ,camera calibration technique has great theo‐retical value and practical value .This paper focuses on the binocular stereo vision camera calibration technique to analyze the binocular camera calibration method based on OpenCV .OpenCV camera calibration based on binocular is more flexible than traditional scaling techniques ,and has a good calibration accuracy .%摄像机标定技术作为双目立体视觉领域的一个基础性研究课题,具有很大的理论研究价值和实际应用价值。论文围绕双目立体视觉中的双目摄像机标定技术,分析基于OpenCV的双目摄像机标定的方法。基于OpenCV的双目摄像机标定比传统的定标技术更为灵活,并且具有不错的定标精度。

  14. 双目视觉的立体标定方法%Stereo calibration method of binocular vision

    Institute of Scientific and Technical Information of China (English)

    刘俸材; 谢明红; 王伟

    2011-01-01

    为实现双目视觉系统的立体标定,分析了摄像机成像模型,并充分考虑了透镜的径向畸变和切向畸变,提出了一种新的立体标定算法.该算法利用张正友的灵活标定算法,初步求取摄像机的内参数,结合Brown算法并提取图像中角点的子像素级坐标,精确求取摄像机内参数和畸变向量.为方便后续的图像校正,基于前面的单个摄像机标定,通过计算空间中的景物点在左右摄像机成像平面上盼位置关系,计算出双目视觉系统中两个摄像机之间的旋转矩阵R和平移向量T,从而实现了立体标定.实验结果表明,该算法能取得较高的精度,可以应用于双目视觉系统.%In order to realize stereo calibration for binocular vision system, firstly, the image model of camera with a full consideration of radial distortion and tangential distortion of lens is analyzed, and a new method of stereo calibration is proposed. The flexible calibration method of Zhang Zhengyou is used to achieve the initial value of the camera's intrinsic parameters, and combined with the arithmetic of Brown, sub-pixel coordinates of images' comer point are extracted. Through this method, it calculates the intrinsic parameters and distortion vector accurately. Hereafter, based on the single camera calibration aforementioned and calculation of the position relationship of spatial point projected to the left and right cameras' imaging planes which helps to work out the rotation matrix R and translation vector T between the two cameras of the binocular stereo vision system, finally the stereo calibration is achieved. All experimental results show that this calculation method acquires higher precision, and can be applied to binocular system.

  15. Phase-Based Binocular Perception of Motion in Depth: Cortical-Like Operators and Analog VLSI Architectures

    Directory of Open Access Journals (Sweden)

    Silvio P. Sabatini

    2003-06-01

    Full Text Available We present a cortical-like strategy to obtain reliable estimates of the motions of objects in a scene toward/away from the observer (motion in depth, from local measurements of binocular parameters derived from direct comparison of the results of monocular spatiotemporal filtering operations performed on stereo image pairs. This approach is suitable for a hardware implementation, in which such parameters can be gained via a feedforward computation (i.e., collection, comparison, and punctual operations on the outputs of the nodes of recurrent VLSI lattice networks, performing local computations. These networks act as efficient computational structures for embedded analog filtering operations in smart vision sensors. Extensive simulations on both synthetic and real-world image sequences prove the validity of the approach that allows to gain high-level information about the 3D structure of the scene, directly from sensorial data, without resorting to explicit scene reconstruction.

  16. Performance and results from the commissioning of the first acquisition, guiding, and wavefront sensing units for the Large Binocular Telescope

    Science.gov (United States)

    Storm, Jesper; Hill, John; Miller, Douglas; Rakich, Andrew; Thompson, David; Brynnel, Joar; Hahn, Thomas; Heidt, Jochen; Popow, Emil

    2010-07-01

    We present the results from the commisioning of the first three off-axis Acquisition, Guiding and Wavefront Sensing Units on the Large Binocular Telescope. In particular we report on the performance of the units with respect to image quality, optical efficiency and scattered light. We also present the procedure for calibrating the stage coordinate system astrometrically to the focal plane coordinates of the telescope as well as the positional performance of the system. The first of a total of four units was mounted on the telescope in October 2007 and in the mean time three units have been mounted on the telescope. The units have been used for commisioning of the focal stations as well as for scientific observations since the end of 2008 with LUCIFER-I, the near-IR images and MOS spectrograph

  17. Binocular neurons in parastriate cortex: interocular 'matching' of receptive field properties, eye dominance and strength of silent suppression.

    Directory of Open Access Journals (Sweden)

    Phillip A Romo

    Full Text Available Spike-responses of single binocular neurons were recorded from a distinct part of primary visual cortex, the parastriate cortex (cytoarchitectonic area 18 of anaesthetized and immobilized domestic cats. Functional identification of neurons was based on the ratios of phase-variant (F1 component to the mean firing rate (F0 of their spike-responses to optimized (orientation, direction, spatial and temporal frequencies and size sine-wave-luminance-modulated drifting grating patches presented separately via each eye. In over 95% of neurons, the interocular differences in the phase-sensitivities (differences in F1/F0 spike-response ratios were small (≤ 0.3 and in over 80% of neurons, the interocular differences in preferred orientations were ≤ 10°. The interocular correlations of the direction selectivity indices and optimal spatial frequencies, like those of the phase sensitivies and optimal orientations, were also strong (coefficients of correlation r ≥ 0.7005. By contrast, the interocular correlations of the optimal temporal frequencies, the diameters of summation areas of the excitatory responses and suppression indices were weak (coefficients of correlation r ≤ 0.4585. In cells with high eye dominance indices (HEDI cells, the mean magnitudes of suppressions evoked by stimulation of silent, extra-classical receptive fields via the non-dominant eyes, were significantly greater than those when the stimuli were presented via the dominant eyes. We argue that the well documented 'eye-origin specific' segregation of the lateral geniculate inputs underpinning distinct eye dominance columns in primary visual cortices of mammals with frontally positioned eyes (distinct eye dominance columns, combined with significant interocular differences in the strength of silent suppressive fields, putatively contribute to binocular stereoscopic vision.

  18. Callosal connections of primary visual cortex predict the spatial spreading of binocular rivalry across the visual hemifields

    Directory of Open Access Journals (Sweden)

    Erhan eGenc

    2011-12-01

    Full Text Available In binocular rivalry, presentation of different images to the separate eyes leads to conscious perception alternating between the two possible interpretations every few seconds. During perceptual transitions, a stimulus emerging into dominance can spread in a wave-like manner across the visual field. These traveling waves of rivalry dominance have been successfully related to the cortical magnification properties and functional activity of early visual areas, including the primary visual cortex (V1. Curiously however, these traveling waves undergo a delay when passing from one hemifield to another. In the current study, we used diffusion tensor imaging (DTI to investigate whether the strength of interhemispheric connections between the left and right visual cortex might be related to the delay of traveling waves across hemifields. We measured the delay in traveling-wave times (ΔTWT in nineteen participants and repeated this test 6 weeks later to evaluate the reliability of our behavioral measures. We found large interindividual variability but also good test-retest reliability for individual measures of ΔTWT. Using DTI in connection with fiber tractography, we identified parts of the corpus callosum connecting functionally defined visual areas V1-V3. We found that individual differences in ΔTWT was reliably predicted by the diffusion properties of transcallosal fibers connecting left and right V1, but observed no such effect for neighboring transcallosal visual fibers connecting V2 and V3. Our results demonstrate that the anatomical characteristics of topographically specific transcallosal connections predict the individual delay of interhemispheric traveling waves, providing further evidence that V1 is an important site for neural processes underlying binocular rivalry.

  19. Duality in binocular rivalry: distinct sensitivity of percept sequence and percept duration to imbalance between monocular stimuli.

    Directory of Open Access Journals (Sweden)

    Chen Song

    Full Text Available BACKGROUND: Visual perception is usually stable and accurate. However, when the two eyes are simultaneously presented with conflicting stimuli, perception falls into a sequence of spontaneous alternations, switching between one stimulus and the other every few seconds. Known as binocular rivalry, this visual illusion decouples subjective experience from physical stimulation and provides a unique opportunity to study the neural correlates of consciousness. The temporal properties of this alternating perception have been intensively investigated for decades, yet the relationship between two fundamental properties - the sequence of percepts and the duration of each percept - remains largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: Here we examine the relationship between the percept sequence and the percept duration by quantifying their sensitivity to the strength imbalance between two monocular stimuli. We found that the percept sequence is far more susceptible to the stimulus imbalance than does the percept duration. The percept sequence always begins with the stronger stimulus, even when the stimulus imbalance is too weak to cause a significant bias in the percept duration. Therefore, introducing a small stimulus imbalance affects the percept sequence, whereas increasing the imbalance affects the percept duration, but not vice versa. To investigate why the percept sequence is so vulnerable to the stimulus imbalance, we further measured the interval between the stimulus onset and the first percept, during which subjects experienced the fusion of two monocular stimuli. We found that this interval is dramatically shortened with increased stimulus imbalance. CONCLUSIONS/SIGNIFICANCE: Our study shows that in binocular rivalry, the strength imblanace between monocular stimuli has a much greater impact on the percept sequence than on the percept duration, and increasing this imbalance can accelerate the process responsible for the percept sequence.

  20. Disfunciones visuo-perceptivas, oculomotoras, acomodativas y binoculares en niños con trastornos por déficit de atención e hiperactividad

    OpenAIRE

    Pardo Pérez, María Carmen

    2009-01-01

    1) Determinar el grado de desarrollo de las habilidades visuoperceptivas, oculomotoras, acomodativas y binoculares en estudiantes con TDAH. 2) Comparar las habilidades visuales y visuoperceptivas entre un grupo de estudiantes con TDAH y otro que no presenta este trastorno. 3) Analizar qué habilidades visuoperceptivas (discriminación, memoria visual, figura-fondo, integración visual…) y oculomotoras presentan unos valores más deteriorados en el grupo de estudiantes que presentan...

  1. Binocular Lens Treatment in Tree Shrews: Effect of Age and Comparison of Plus Lens Wear with Recovery from Minus Lens-induced Myopia

    OpenAIRE

    Siegwart, John T.; Norton, Thomas T.

    2010-01-01

    We examined normal emmetropization and the refractive responses to binocular plus or minus lenses in young (late infantile) and juvenile tree shrews. In addition, recovery from lens-induced myopia was compared with the response to a similar amount of myopia produced with plus lenses in age-matched juvenile animals. Normal emmetropization was examined with daily noncycloplegic autorefractor measures from 11 days after natural eye-opening (days of visual experience [VE]) when the eyes were in t...

  2. A Technique for Binocular Stereo Vision System Calibration by the Nonlinear Optimization and Calibration Points with Accurate Coordinates

    International Nuclear Information System (INIS)

    With the increasing need for higher accuracy measurement in computer vision, the precision of camera calibration is a more important factor. The objective of stereo camera calibration is to estimate the intrinsic and extrinsic parameters of each camera. We presented a high-accurate technique to calibrate binocular stereo vision system having been mounted the locations and attitudes, which was realized by combining nonlinear optimization method with accurate calibration points. The calibration points with accurate coordinates, were formed by an infrared LED moved with three-dimensional coordinate measurement machine, which can ensure indeterminacy of measurement is 1/30000. By using bilinear interpolation square-gray weighted centroid location algorithm, the imaging centers of the calibration points can be accurately determined. The accuracy of the calibration is measured in terms of the accuracy in the reconstructing calibration points through triangulation, the mean distance between reconstructing point and given calibration point is 0.039mm. The technique can satisfy the goals of measurement and camera accurate calibration

  3. A temperature inversion in WASP-33b? Large Binocular Telescope occultation data confirm significant thermal flux at short wavelengths

    CERN Document Server

    von Essen, C; Albrecht, S; Antoci, V; Smith, A M S; Dreizler, S; Strassmeier, K G

    2015-01-01

    We observed a secondary eclipse of WASP-33b quasi-simultaneously in the optical (~0.55 {\\mu}m) and the near-infrared (~1.05 {\\mu}m) using the 2x8.4 m Large Binocular Telescope. WASP-33 is a {\\delta} Scuti star pulsating with periods comparable to the eclipse duration, making the determination of the eclipse depth challenging. We use previously determined oscillation frequencies to model and remove the pulsation signal from the light curves, isolating the secondary eclipse. The determined eclipse depth is dF = 1.03 +/- 0.34 parts per thousand, corresponding to a brightness temperature of Tb = 3398 +/- 302 K. Combining previously published data with our new measurement we find the equilibrium temperature of WASP-33b to be Tb = 3358 +/- 165 K. We compare all existing eclipse data to a blackbody spectrum, to a carbon-rich non-inverted model and to a solar composition model with an inverted temperature structure. We find that current available data on WASP-33b's atmosphere can be best represented by a simple black...

  4. The Cepheid distance to the maser-host galaxy NGC 4258: Studying systematics with the Large Binocular Telescope

    CERN Document Server

    Fausnaugh, M M; Gerke, J R; Macri, L M; Riess, A G; Stanek, K Z

    2014-01-01

    We identify and phase a sample of 81 Cepheids in the maser-host galaxy NGC 4258 using the Large Binocular Telescope (LBT), and obtain calibrated mean magnitudes in up to 4 filters for a subset of 43 Cepheids using archival HST data. We employ 3 models to study the systematic effects of extinction, the assumed extinction law, and metallicity on the Cepheid distance to NGC 4258. We find a correction to the Cepheid colors consistent with a grayer extinction law in NGC 4258 compared to the Milky Way ($R_V =4.9$), although we believe this is indicative of other systematic effects. If we combine our Cepheid sample with previously known Cepheids, we find a significant metallicity adjustment to the distance modulus of $\\gamma_1 = -0.60 \\pm 0.21$ mag/dex, for the Zaritsky et al. (1994) metallicity scale, as well as a weak trend of Cepheid colors with metallicity. Conclusions about the absolute effect of metallicity on Cepheid mean magnitudes appear to be limited by the available data on the metallicity gradient in NGC...

  5. Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

    CERN Document Server

    Defrère, D; Downey, E; Böhm, M; Danchi, W C; Durney, O; Ertel, S; Hill, J M; Hoffmann, W F; Mennesson, B; Millan-Gabet, R; Montoya, M; Pott, J -U; Skemer, A; Spalding, E; Stone, J; Vaz, A

    2016-01-01

    The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 $\\mu$m). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illus...

  6. Neuromagnetic evidence that the right fusiform face area is essential for human face awareness: An intermittent binocular rivalry study.

    Science.gov (United States)

    Kume, Yuko; Maekawa, Toshihiko; Urakawa, Tomokazu; Hironaga, Naruhito; Ogata, Katsuya; Shigyo, Maki; Tobimatsu, Shozo

    2016-08-01

    When and where the awareness of faces is consciously initiated is unclear. We used magnetoencephalography to probe the brain responses associated with face awareness under intermittent pseudo-rivalry (PR) and binocular rivalry (BR) conditions. The stimuli comprised three pictures: a human face, a monkey face and a house. In the PR condition, we detected the M130 component, which has been minimally characterized in previous research. We obtained a clear recording of the M170 component in the fusiform face area (FFA), and found that this component had an earlier response time to faces compared with other objects. The M170 occurred predominantly in the right hemisphere in both conditions. In the BR condition, the amplitude of the M130 significantly increased in the right hemisphere irrespective of the physical characteristics of the visual stimuli. Conversely, we did not detect the M170 when the face image was suppressed in the BR condition, although this component was clearly present when awareness for the face was initiated. We also found a significant difference in the latency of the M170 (human

  7. The adaptive secondary mirror for the Large Binocular Telescope: optical acceptance test and preliminary on-sky commissioning results

    Science.gov (United States)

    Riccardi, Armando; Xompero, Marco; Briguglio, Runa; Quirós-Pacheco, Fernando; Busoni, Lorenzo; Fini, Luca; Puglisi, Alfio; Esposito, Simone; Arcidiacono, Carmelo; Pinna, Enrico; Ranfagni, Piero; Salinari, Piero; Brusa, Guido; Demers, Richard; Biasi, Roberto; Gallieni, Daniele

    2010-07-01

    The Large Binocular Telescope (LBT) has two adaptive secondary mirrors based on 672 voice-coil force actuators. The shape of the mirror is controlled using internal metrology based on co-located capacitive sensors. The first mirror unit is currently mounted on LBT for on-sky commissioning as part of the First Light Adaptive Optics System (FLAO). During spring-time 2009 the optical acceptance test was performed using the 14-m optical test tower at the Osservatorio Astrofisico di Arcetri (INAF) showing the capability of flattening the shell at the level of 14nm rms residual surface error. This paper reports the optical layout, calibration procedures and results of the optical acceptance test. Moreover we report the first results obtained during the early runs of FLAO commissioning showing the ability of the mirror to compensate for atmospheric turbulence with extremely high Strehl ratio values (better than 80% in H-band) as permitted by the largest number of correcting degrees of freedom currently available on-sky for astronomical telescopes.

  8. Embedded Binocular Stereo Vision Ranging System%嵌入式双目立体视觉测距系统

    Institute of Scientific and Technical Information of China (English)

    文成维; 陈文建; 詹泳

    2012-01-01

    设计和研究了一种基于S3C2440硬件平台和嵌入式Linux双目立体视觉测距系统.该系统通过使用两个USB摄像头同步采集图像数据,并利用OpenCV对采集的两幅图像的数据进行处理,计算目标物在两幅图像中的像素偏差,进而算出目标物到摄像头平面的距离,在论文中以车牌作为目标物.同时该系统用Qt/Embedded实现LED实时显示图像和数据.整个系统建立在嵌入式架构上,能独立完成图像采集,数据处理,实时显示等功能.只要改变定位算法,则能测出任意目标物的距离.%The paper designs and researches a binocular stereo measuring system based on S3C2440 hardware platform and embedded Linux. The system captures images data in synchronization by using 2 USB cameras, and then processes the images data in OpenCV Lib. Finally, calculate the pixel deviation of the target in two images, and then calculate the distance from the target to camera plane, license plate be seen as the target in the paper. At the same time, the system displays the images and dates on LED with Qt/Embedded GUI in real time. The whole system is built on an embedded architecture, able to capture images and process data and real-time display data independently. When change location algorithm, we can calculate the distance of any targets.

  9. Screening for retinopathy of prematurity-a comparison between binocular indirect ophthalmoscopy and RetCam 120

    Directory of Open Access Journals (Sweden)

    Shah Parag

    2006-01-01

    Full Text Available Aim: To compare the photographic screening for retinopathy of prematurity (ROP using RetCam 120 with binocular indirect ophthalmoscope (BIO, which is the current gold standard. Setting and Design: Prospective, comparative study. Materials and Methods: A total of 87 RetCam examinations were performed on 27 premature babies. They were stored in a separate file after deleting the identifying information. At the same visit using the BIO with scleral depression, an experienced vitreoretinal surgeon evaluated the fundus in detail. A masked examiner then evaluated the RetCam photographs for presence or absence of ROP, the stage and zone of the disease, and the presence or absence of plus disease. These data were then compared with the BIO findings to determine the sensitivity, specificity, and the positive and negative predictive values of the method. Results: ROP was detected in 63 of 87 examinations by BIO and in 56 of 87 RetCam examinations. Nine RetCam examinations were false-negative and two were false-positive. Sensitivity of RetCam was 85.71% (54/63 and specificity was 91.66% (22/24. The positive and negative predictive values were 96.43% and 70.97% respectively. Conclusion: Nine cases having ROP were missed by the RetCam. All these cases were either in zone 3 or the outer part of zone 2, which later regressed. These were missed mostly because of the restricted mobility of the camera head caused by its size and the barrier caused by the lid speculum arms. No case of threshold ROP was missed. RetCam may replace BIO for screening of ROP.

  10. Large Binocular Telescope/LUCIFER spectroscopy: kinematics of a compact early-type galaxy at z ≃ 1.4

    Science.gov (United States)

    Longhetti, M.; Saracco, P.; Gargiulo, A.; Tamburri, S.; Lonoce, I.

    2014-04-01

    We present a high signal-to-noise ratio (S/N > 10) medium-resolution (R = 2000) Large Binocular Telescope/LUCIFER spectrum of the early-type galaxy (ETG) S2F1-142 at z ≃ 1.4. By means of the CaT line at 8662 Å, we measured its redshift z = 1.386 ± 0.001 and we estimated its velocity dispersion σ v=340^{-60}_{+120} km s-1. Its corresponding virial mass is 3.9 × 1011 M⊙, compatible with the stellar mass estimates obtained assuming initial mass functions (IMFs) less dwarf rich than the Salpeter one. S2F1-142 is a compact galaxy with Re = 3.1 ± 0.2 kpc, i.e. an effective radius more than three times smaller than the average Re of ETGs with the same mass in the local Universe. At the same time, we found local and high-redshift galaxies with a similar mass content and similar effective radius confirming that it is fully consistent with the already available measures of Re and σv both in the local and in the distant Universe. Considering the distribution of Re and σv as a function of the stellar mass content of ETGs, both in the local and in the distant Universe, we noticed that the measured velocity dispersions of the more compact galaxies are on average slightly lower than expected on the basis of their compactness and the virial theorem, suggesting that (i) their dark matter content is lower than in the more diffuse galaxies and/or (ii) their luminosity profiles are steeper than in the more diffuse galaxies and/or (iii) their larger compactness is an apparent effect caused by the overestimate of their stellar mass content (due to bottom lighter IMF and/or systematic affecting the stellar mass estimates).

  11. 3D-MAD: A Full Reference Stereoscopic Image Quality Estimator Based on Binocular Lightness and Contrast Perception.

    Science.gov (United States)

    Zhang, Yi; Chandler, Damon M

    2015-11-01

    Algorithms for a stereoscopic image quality assessment (IQA) aim to estimate the qualities of 3D images in a manner that agrees with human judgments. The modern stereoscopic IQA algorithms often apply 2D IQA algorithms on stereoscopic views, disparity maps, and/or cyclopean images, to yield an overall quality estimate based on the properties of the human visual system. This paper presents an extension of our previous 2D most apparent distortion (MAD) algorithm to a 3D version (3D-MAD) to evaluate 3D image quality. The 3D-MAD operates via two main stages, which estimate perceived quality degradation due to 1) distortion of the monocular views and 2) distortion of the cyclopean view. In the first stage, the conventional MAD algorithm is applied on the two monocular views, and then the combined binocular quality is estimated via a weighted sum of the two estimates, where the weights are determined based on a block-based contrast measure. In the second stage, intermediate maps corresponding to the lightness distance and the pixel-based contrast are generated based on a multipathway contrast gain-control model. Then, the cyclopean view quality is estimated by measuring the statistical-difference-based features obtained from the reference stereopair and the distorted stereopair, respectively. Finally, the estimates obtained from the two stages are combined to yield an overall quality score of the stereoscopic image. Tests on various 3D image quality databases demonstrate that our algorithm significantly improves upon many other state-of-the-art 2D/3D IQA algorithms. PMID:26186775

  12. Imaging with LINC-NIRVANA, the Fizeau interferometer of the Large Binocular Telescope: state of the art and open problems

    International Nuclear Information System (INIS)

    LINC-NIRVANA (LN) is the Fizeau interferometer of the Large Binocular Telescope which consists of two 8.4 m mirrors with a center-to-center distance of 14.4 m, hence providing a maximum path of 22.8 m in the direction of the baseline joining the two centers. LN is a true imager since interference occurs in the focal plane and not in the aperture plane as with essentially all the existing interferometers. However, an LN image is characterized by an anisotropic resolution: that of a 22.8 m mirror in the direction of the baseline and that of a 8.4 m mirror in the orthogonal direction. In order to obtain a unique image with a high and isotropic resolution, several images must be detected with different orientations of the baseline and suitably processed. Therefore, the instrument will routinely require the use of image reconstruction methods for providing astronomical images with unprecedented resolution, in principle ten times the resolution of the Hubble Space Telescope. This review concerns the image reconstruction problem for LN and is based essentially on our work. After a description of the main features of the telescope and of the interferometer, it contains a discussion of the problem and of the approximations introduced in its formulation. In short, it is reduced to multiple-image deconvolution with Poisson data. Similarity with the image reconstruction problem in emission tomography is stressed and utilized for introducing suitable iterative reconstruction methods. These methods are extended to regularized versions of the problem. Efficiency is another important issue because the size of LN images is of the order of 4.2 megapixels; therefore, acceleration methods are also discussed. All methods are tested on synthetic images because, even if the instrument is in an advanced stage of realization, it will be presumably operative in 2014. The algorithms of the proposed image reconstruction methods are implemented in the Software Package AIRY (astronomical image

  13. Amblyopia and Binocular Vision

    OpenAIRE

    Birch, Eileen E.

    2012-01-01

    Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3% to 3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of bin...

  14. Driving with binocular visual field loss? A study on a supervised on-road parcours with simultaneous eye and head tracking.

    Directory of Open Access Journals (Sweden)

    Enkelejda Kasneci

    Full Text Available Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs that may critically interfere with quality of life and driving licensure. The aims of this study were (i to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed of ten patients with homonymous visual field defects (HP, including four patients with right (HR and six patients with left homonymous visual field defects (HL, ten glaucoma patients (GP, and twenty age and gender-related ophthalmologically healthy control subjects (C during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on

  15. An investigation on binocular summation response of visual evoked potential in children with hyperopia amblyopia%弱视儿童双眼总和视觉诱发电位变化的研究

    Institute of Scientific and Technical Information of China (English)

    于春红; 廖瑜俊; 杨洋; 邓燕; 彭小维; 鄢涛; 殷小龙

    2009-01-01

    Objective Conventional examination for vision function adopts subjective psychophysics methods.Pattern visual evoked potential (P-VEP) binocular summation response is a new objective way for the test of vision function.But its clinical value in evaluating vision function of amblyopia children is still in controversy.This study was to explore the binocular vision and the feature of P-VEP binocular summation in children with amblyopia and evaluate the significance of P-VEP binocular summation in binocular vision.MethodsThis is a case-controlled study.P-VEP binocular summation response and single ocular P-VEP response was respectively recorded in 151 hyperopia amblyopia children and 80 age- and gender-matched normal children.P-VEP response from children with hyperopia amblyopia was recorded under the corrected vision.The hyperopia amblyopia was diagnosed based on the standard of National Children Amblyopia and Strabismus Prevention and Treatment Working Group.The feature of P-VEP binocular summation was further analyzed and compared with monocular VEP response.Informed consent was obtained from each subject or custodian prior to the trail.ResultsNo significant difference was found in latency between P-VEP binocular summation response and monocular P-VEP response whether amblyopia children or normal children(P>0.05).Binocular response/monocular response value in amblyopia children was lower than that in normal children(P<0.05).Binocular response/monocular response value in mild or moderate amblyopia children was higher than that in severe amblyopia children(P<0.05).Binocular response/monocular response value was significantly reduced in the children with binocular vision than in the children without binocular vision (P<0.05).ConclusionP-VEP binocular vision,acting as an evaluation factor,could impartially reflect the function of binocular vision of amblyopia children.%目的 探讨弱视儿童双眼视功能及总和图形视觉诱发电位(P-VEP)反应的特

  16. 基于投影直方图匹配的双目视觉跟踪算法%Binocular object tracking method using projection histogram matching

    Institute of Scientific and Technical Information of China (English)

    王杰; 蒋明敏; 花晓慧; 鲁守银; 李金屏

    2015-01-01

    An effective object location and tracking method is proposed for a robot manipulator's binocular visual servo system by utilizing projection histogram matching and the epipolar geometric constraint. The object is selected manually in the two vision systems, then the horizontal and vertical projection histograms, in multiple color spaces of the selected object, are extracted as matching templates for these two vision systems. The object in one vision system can be tracked by making use of the principle of moving continuity and the matching templates of the projec-tion histograms in multiple color spaces. In the other vision system, the object is located roughly based on epipolar geometric constraint, and then it can be tracked accurately using the same method which is used in the first vision. The proposed method describes the object's structural information by using horizontal and vertical projection histo-grams, and realizes the function of object tracking and registration in the binocular visual system, which is helpful in the precise location and visual measurement of the tracked object. The experiment results indicate that this meth-od can realize the binocular object tracking with high efficiency and strong robustness.%为了在机器人机械手双目视觉伺服系统中跟踪并精确定位目标的空间位置,提出了一种利用投影直方图匹配和极线几何约束的目标跟踪方法. 分别在2个视觉中人工标定目标,并提取目标在多颜色空间的水平、垂直投影直方图作为匹配模板;在一个视觉中利用目标的运动一致性原则和投影直方图匹配搜索并跟踪目标;在另一个视觉中依据双目视觉系统的极线几何原理限定目标搜索范围,搜索并定位目标. 该方法利用水平、垂直投影直方图描述目标的结构信息,同时完成了双目视觉系统中的目标跟踪与配准功能,有利于目标的精确定位和视觉测量. 实验结果表明,该方法可在双目视

  17. Autonomous Mapping for Robot Using a Combination of Binocular Stereo Vision and GSOM Algorithm%双目立体视觉和GSOM相结合的机器自主地图构建方法

    Institute of Scientific and Technical Information of China (English)

    于乃功; 王丽

    2011-01-01

    双目立体视觉和自组织可增长特征映射图GSOM (Growing Self-organizing Map)相结合的机器人地图构建方法首先利用双目立体摄像机采集图像,借助双目立体视觉处理技术,将采集到的图像信息转化成神经网络的训练样本;然后利用GSOM的地图绘制算法,通过不断增加新的神经元实现网络规模的增长,用441个SOM神经元便表示了2000个样本点的环境特征信息的拓扑地图,体现了对输入样本分布的逼近特性;实验结果表明双目立体视觉和GSOM相结合的机器人自主地图构建方法可行,并表现出类似生物的自主智能行为.%Autonomous mapping for robot using a combination of binocular stereo vision and GSOM (Growing Self-organizing Map) Algorithm collects images using a binocular stereo camera. After treatment of binocular stereo vision technology, image information generates neural network training samples. Appling GSOM algorithm by continuously increasing new neurons in the growth of network scale, the algorithm uses 441 SOM neurons generate a topologic map which describes 2000 sample' s environmental information and reflects the approximation characteristics of input data distribution. Through testing GSOM mapping algorithm, the experimental results show that autonomous mapping for robot using a combination of binocular stereo vision and GSOM algorithm is feasible; and the system shows similar biological behaviours of autonomous intelligence.

  18. 基于双目视觉的机器人自定位方法研究%Robot autonmouls localization method study based on binocular vision

    Institute of Scientific and Technical Information of China (English)

    张华; 夏菠

    2015-01-01

    研究了一种利用双目立体视觉的机器人自定位方法。首先提取双目图像序列的 Harris 角点特征,并计算其水平与垂直方向上的 Sobel 响应,基于此响应,采用绝对误差累计的最小窗口查找(SAD)原理进行立体匹配。将改进的 RANSAC 算法用于特征匹配点优化中,利用高斯牛顿迭代法求解机器人位姿,实现了机器人的自定位。室内、外实验,及与 BoofCV 视觉库中的立体视觉定位算法的对比分析,证明该方法在运算速度、定位精度和稳定性等方面均能满足实际应用需求。%A robot autonomous localization method based on binocular vision image sequences was studied.Harris corner features were extracted with the binocular vision image sequence and Sobel fil-ter responses of horizontal and vertical was simply compared to each other by using sum of absolute differences error metric,and matching feature points based on the responses value.The improved RANSAC algorithm was used for feature matching optimization.Finally the gauss-newton iterative method was used for solving over determined nonlinear equations of robot pose estimation,and the o-rientation of the robot was realized.Through indoor and outdoor scene experiments,as well as com-paring with the stereo visual odometry algorithm in BoofCV visual library,experiments show that the proposed approach can meet the application requirements in terms of accuracy,stability and run-time.

  19. 基于双目视觉的机器人自定位方法研究%Robot autonmouls localization method study based on binocular vision

    Institute of Scientific and Technical Information of China (English)

    张华; 夏菠

    2015-01-01

    A robot autonomous localization method based on binocular vision image sequences was studied.Harris corner features were extracted with the binocular vision image sequence and Sobel fil-ter responses of horizontal and vertical was simply compared to each other by using sum of absolute differences error metric,and matching feature points based on the responses value.The improved RANSAC algorithm was used for feature matching optimization.Finally the gauss-newton iterative method was used for solving over determined nonlinear equations of robot pose estimation,and the o-rientation of the robot was realized.Through indoor and outdoor scene experiments,as well as com-paring with the stereo visual odometry algorithm in BoofCV visual library,experiments show that the proposed approach can meet the application requirements in terms of accuracy,stability and run-time.%研究了一种利用双目立体视觉的机器人自定位方法。首先提取双目图像序列的 Harris 角点特征,并计算其水平与垂直方向上的 Sobel 响应,基于此响应,采用绝对误差累计的最小窗口查找(SAD)原理进行立体匹配。将改进的 RANSAC 算法用于特征匹配点优化中,利用高斯牛顿迭代法求解机器人位姿,实现了机器人的自定位。室内、外实验,及与 BoofCV 视觉库中的立体视觉定位算法的对比分析,证明该方法在运算速度、定位精度和稳定性等方面均能满足实际应用需求。

  20. Large Binocular Telescope and Sptizer Spectroscopy of Star-forming Galaxies at 1 < z < 3: Extinction and Star Formation Rate Indicators

    Science.gov (United States)

    Rujopakarn, W.; Rieke, G. H.; Papovich, C. J.; Weiner, B. J.; Rigby, Jane; Rex, M.; Bian, F.; Kuhn, O. P.; Thompson, D.

    2012-01-01

    We present spectroscopic observations in the rest-frame optical and near- to mid-infrared wavelengths of four gravitationally lensed infrared (IR) luminous star-forming galaxies at redshift 1 LUCIFER instrument on the Large Binocular Telescope and the Infrared Spectrograph on Spitzer. The sample was selected to represent pure, actively star-forming systems, absent of active galactic nuclei. The large lensing magnifications result in high signal-to-noise spectra that can probe faint IR recombination lines, including Paa and Bra at high redshifts. The sample was augmented by three lensed galaxies with similar suites of unpublished data and observations from the literature, resulting in the final sample of seven galaxies. We use the IR recombination lines in conjunction with Ha observations to probe the extinction, Av, of these systems, as well as testing star formation rate (SFR) indicators against the SFR measured by fitting spectral energy distributions to far-IR photometry. Our galaxies occupy a range of Av from 0 to 5.9 mag, larger than previously known for a similar range of IR luminosities at these redshifts. Thus, estimates of SFR even at z 2 must take careful count of extinction in the most IR luminous galaxies.We also measure extinction by comparing SFR estimates from optical emission lines with those from far- IR measurements. The comparison of results from these two independent methods indicates a large variety of dust distribution scenarios at 1 < z < 3. Without correcting for dust extinction, the Ha SFR indicator underestimates the SFR; the size of the necessary correction depends on the IR luminosity and dust distribution scenario. Individual SFR estimates based on the 6.2µm polycyclic aromatic hydrocarbon emission line luminosity do not show a systematic discrepancy with extinction, although a considerable, 0.2 dex, scatter is observed.

  1. 双目视觉的台球桌面的三维重构%3D Reconstruction of Desktop of Table Tennis Based on the Binocular Vision

    Institute of Scientific and Technical Information of China (English)

    张旭飞; 王朝立; 袁伟

    2013-01-01

    At present, with the rapid development of the computer technologies which has grown dramatically, and there are more and more sports competition where some high and new technologies are emploited as the electronic referee to assist referee to do the decisions, in order to achieve the spirit of fair play which respected by Olympic. During this process, the camera plays an important role in computer vision. 3D reconstruction is a process based on a single view or multi-view images to obtain the 3D information in the field of computer vision. In this paper, in order to complete a task about three-dimensional reconstruction of desktop of Table tennis, we take 3D reconstruction technologies in computer vision as the mainly research object, including specific details about the theoretical knowledge on the binocular vision and the reconstruction algorithm provided by the computer vision library OpenCV. The 3D reconstruction of billiards desktop have strong practical significance, which laid a good foundation for the electronic referee to work in the billiards competition.%  随着计算机技术的迅猛发展,在越来越多的体育比赛中纷纷出现了电子裁判来辅助裁判进行判罚工作,以实现奥林匹克的公平竞赛精神。而在实现这种数字化裁判的过程中,摄像机在计算机视觉中起着重要的作用,三维重构就是根据单视图或者多视图的图像重建三维信息的过程。主要以计算机视觉中的三维重构技术作为研究对象,具体详述了有关双目视觉的一些理论知识,充分利用计算机视觉库OpenCV提供的重建算法,来完成对台球桌面的三维重构工作。台球桌面的三维重构具有很强的现实意义,为电子裁判进入桌球比赛打下了良好的基础。

  2. 3D Reconstruction of Desktop of Table Tennis Based on the Binocular Vision%双目视觉的台球桌面的三维重构

    Institute of Scientific and Technical Information of China (English)

    张旭飞; 王朝立; 袁伟

    2013-01-01

    At present, with the rapid development of the computer technologies which has grown dramatically, and there are more and more sports competition where some high and new technologies are emploited as the electronic referee to assist referee to do the decisions, in order to achieve the spirit of fair play which respected by Olympic. During this process, the camera plays an important role in computer vision. 3D reconstruction is a process based on a single view or multi-view images to obtain the 3D information in the field of computer vision. In this paper, in order to complete a task about three-dimensional reconstruction of desktop of Table tennis, we take 3D reconstruction technologies in computer vision as the mainly research object, including specific details about the theoretical knowledge on the binocular vision and the reconstruction algorithm provided by the computer vision library OpenCV. The 3D reconstruction of billiards desktop have strong practical significance, which laid a good foundation for the electronic referee to work in the billiards competition.%  随着计算机技术的迅猛发展,在越来越多的体育比赛中纷纷出现了电子裁判来辅助裁判进行判罚工作,以实现奥林匹克的公平竞赛精神。而在实现这种数字化裁判的过程中,摄像机在计算机视觉中起着重要的作用,三维重构就是根据单视图或者多视图的图像重建三维信息的过程。主要以计算机视觉中的三维重构技术作为研究对象,具体详述了有关双目视觉的一些理论知识,充分利用计算机视觉库OpenCV提供的重建算法,来完成对台球桌面的三维重构工作。台球桌面的三维重构具有很强的现实意义,为电子裁判进入桌球比赛打下了良好的基础。

  3. Large Binocular Telescope and Spitzer Spectroscopy of Star-forming Galaxies at 1

    Science.gov (United States)

    Rujopakarn, W.; Rieke, G. H.; Papovich, C. J.; Weiner, B. J.; Rigby, J. R.; Rex, M.; Bian, F.; Kuhn, O. P.; Thompson, D.

    2012-08-01

    We present spectroscopic observations in the rest-frame optical and near- to mid-infrared wavelengths of four gravitationally lensed infrared (IR) luminous star-forming galaxies at redshift 1 LUCIFER instrument on the Large Binocular Telescope and the Infrared Spectrograph on Spitzer. The sample was selected to represent pure, actively star-forming systems, absent of active galactic nuclei. The large lensing magnifications result in high signal-to-noise spectra that can probe faint IR recombination lines, including Paα and Brα at high redshifts. The sample was augmented by three lensed galaxies with similar suites of unpublished data and observations from the literature, resulting in the final sample of seven galaxies. We use the IR recombination lines in conjunction with Hα observations to probe the extinction, Av , of these systems, as well as testing star formation rate (SFR) indicators against the SFR measured by fitting spectral energy distributions to far-IR photometry. Our galaxies occupy a range of Av from ~0 to 5.9 mag, larger than previously known for a similar range of IR luminosities at these redshifts. Thus, estimates of SFR even at z ~ 2 must take careful count of extinction in the most IR luminous galaxies. We also measure extinction by comparing SFR estimates from optical emission lines with those from far-IR measurements. The comparison of results from these two independent methods indicates a large variety of dust distribution scenarios at 1 < z < 3. Without correcting for dust extinction, the Hα SFR indicator underestimates the SFR; the size of the necessary correction depends on the IR luminosity and dust distribution scenario. Individual SFR estimates based on the 6.2 μm polycyclic aromatic hydrocarbon emission line luminosity do not show a systematic discrepancy with extinction, although a considerable, ~ 0.2 dex, scatter is observed. The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT

  4. Binocular stereo vision navigation for electric VTOL aircraft%电动VTOL飞行器双目立体视觉导航方法

    Institute of Scientific and Technical Information of China (English)

    张博翰; 蔡志浩; 王英勋

    2011-01-01

    A stereo vision-based navigation method for the electric vertical take-off and landing(VTOL) aircraft to wander safely through an unknown dynamic indoor corridor was researched.The aircraft uses two cameras to obtain images from different locations,and then the theory of binocular stereo vision was used to restore the 3-D coordinates of the feature points in front of the aircraft.Corner matching method was applied to calculate the disparity of the detected corners on the wall.Thus,the horizontal position of unmanned aerial vehicle(UAV) in the corridor was revealed.The area-based stereo matching algorithm was presented to get the dense disparity map of the original image pair,then obstacles were extracted from the disparity map and the navigation points were generated for the UAV to avoid obstacles.Preliminary experiment shows that the method is feasible and can be used as a basis for further research.%研究了在未知的、动态的室内走廊环境中,采用双目立体视觉引导电动VTOL(Vertical Take-Off and Landing)飞行器安全飞行的方法.使用安装在飞机上的两个微型摄像头从不同的位置获取图像,由双目立体视觉理论恢复其周围环境特征点的三维坐标.采用角点匹配方法计算视差,实现无人机在走廊中的横向坐标定位.采用区域灰度相关算法进行立体匹配获取视差图,从视差图上检测出障碍物,并给出避障导航点.初步实验验证表明,该方法可行性较高,可以作为进一步研究的基础.

  5. Dynamic Obstacle Avoidance Based on Binocular Vision for AS-R Mobile Robots%AS-R 移动机器人基于双目视觉的动态避障

    Institute of Scientific and Technical Information of China (English)

    张寒; 张冰蔚

    2016-01-01

    针对移动机器人的动态避障问题,以AS-R移动机器人为平台,设计了一种基于双目视觉的动态避障方法。从双目视觉系统出发,介绍了AS-R机器人的视觉系统,研究了AS-R机器人的运动原理,探讨了图像信息处理的过程;最后设计了两种简单环境下机器人的动态避障,并验证了所提方法的有效性。%Aiming at the problem of obstacle avoidance for mobile robot ,with the platform of AS-R mobile robot ,a novel approach based on binocular vision for dynamic obstacle avoidance was put forward .Starting from binocular vision system ,the paper intro-duced the AS-R robot vision system ,studied the principles of AS-R robot movement ,and discussed the processing of image informa-tion .Experiments based on both simulation platform and ASR robot verified the effectiveness of the proposed approach .

  6. Resultados do implante bilateral de lente intra-ocular multifocal SA-40N no Hospital de Olhos de Minas Gerais Visual outcome with binocular implantation of SA-40N multifocal intraocular lens at "Hospital de Olhos de Minas Gerais"

    Directory of Open Access Journals (Sweden)

    Cristina Moreira Salera

    2005-02-01

    Full Text Available OBJETIVOS: Avaliar os resultados da facoemulsificação com implante bilateral da lente intra-ocular multifocal modelo SA-40N no Hospital de Olhos de Minas Gerais. MÉTODOS: Foram analisados retrospectivamente os prontuários de 58 pacientes (116 olhos submetidos à cirurgia de facoemulsificação com implante binocular de lente intra-ocular multifocal modelo SA-40N. RESULTADOS: O equivalente esférico médio pré-operatório foi +1,55 dioptrias (variando de -4,25 a +6,25 D e no pós-operatório foi -0,59 dioptrias (variando de -2,25 a +1,25 D. No trigésimo dia de pós-operatório 94 olhos (81% apresentavam visão para longe igual a 20/20 com correção. Para a visão de perto binocular 29 (50% pacientes eram capazes de ler J1 sem correção e 25 pacientes (43,1%, J2 sem correção. Comparando-se as acuidades visuais com correção (AVCC antes e após a cirurgia observamos que em 68 olhos (58,6% a AVCC foi mantida, em 33 olhos (28,4% houve ganho de linhas de visão e em 15 olhos (12,9% houve perda de linhas de visão. Quanto às complicações 19 pacientes (32,7% queixavam-se de halos, em três olhos (2,6% ocorreu edema macular cistóide e em cinco olhos (4,3% ocorreu opacificação de cápsula posterior. Em 36 pacientes (62,1% não foi necessária a prescrição de óculos no pós-operatório. CONCLUSÃO: Os resultados deste estudo indicam que a lente intra-ocular multifocal promove redução na dependência do uso dos óculos e grande satisfação do paciente apesar da ocorrência de halos.PURPOSE: To evaluate the outcomes of phacoemulsification with binocular implantation of SA-40N multifocal intraocular lens at the "Hospital de Olhos de Minas Gerais". METHODS: The charts of 58 patients (116 eyes who were submitted to phacoemulsification with binocular implantation of SA-40N multifocal intraocular lens were retrospectively analyzed. RESULTS: The mean preoperative spherical equivalent was +1.55D (ranging from -4.25 to +6.25D and after surgery

  7. BINOCULAR RIVALRY AND NEURAL DYNAMICS*

    OpenAIRE

    Blake, Randolph; Lee, Sang-Hun; Heeger, David

    2008-01-01

    The Gestalt psychologists were fascinated with dynamics evident in visual perception, and they theorized that these dynamics were attributable to ever-changing electrical potentials within topographically organized brain fields. Dynamic field theory, as it was called, was subsequently discredited on grounds that the brain does not comprise a unitary electrical field but, instead, a richly interconnected network of discrete computing elements. Still, this modern conceptualization of brain func...

  8. Large Binocular Telescope - Teilprojekt Lucifer

    OpenAIRE

    Jäger, Klaus; Mandel, Holger

    2010-01-01

    An Lucifer arbeiten die Mannheimer Fachhochschule für Technik und Gestaltung und die Landessternwarte Heidelberg eng zusammen. Das Projekt ist der deutsche Beitrag für ein neues Riesenteleskop in Arizona, USA. Es handelt sich um einen Spektrographen für den nahen Infrarotbereich, der auch als Kamera genutzt werden kann. Seine Besonderheit: Er kann das ferne Weltall erforschen, denn dort haben sich durch den Urknall viele uralte Spektren im Infrarotbereich ergeben, denen Lucifer auf die Spur k...

  9. Viewing the Constellations with Binoculars

    CERN Document Server

    Kambic, Bojan

    2010-01-01

    A guide to practical astronomy. It introduces the reader to some basic (and some not-so-basic) astronomical concepts, and discusses the stars and their evolution, the planets, nebulae, and distant galaxies

  10. 基于OpenCV的双目立体视觉监控跟踪系统%A Binocular Stereo Vision Surveillance Tracking System which Based on Computer Vision Library OpenCV

    Institute of Scientific and Technical Information of China (English)

    万智萍; 叶仕通

    2013-01-01

    Monitoring equipment of the present stage cannot independently obtain the distance information of the target region, and when it is at outside of a certain range, which due to a deeper level of image blur can not identify a specific individual.For the above problems, designing and development of a binocular stereo vision surveillance tracking system which based on computer vision library OpenCV, and combined with self-developed to binocular stereovision ranging Improvement Act and contour search method, which distance measurements and contour recognition can be achieved on the objects within the monitored region.Experimental results show that based binocular stereo vision OpenCV monitoring tracking system is reliable and stable, within a certain range which can to achieve the experimental requirements.%现阶段的监控设备无法自主获取目标区域的距离信息,而且在一定范围之外,由于图像模糊程度加深而无法对特定个体进行识别确认.针对以上存在的问题,设计并开发了基于计算机视觉库OpenCV(IntelOpen Source Computer Vision Library)的双目立体视觉监控跟踪系统.利用OpenCV强大的计算机视觉和图像处理能力,结合自行研究的双目立体视觉测距改进法和轮廓搜索法,能实现对监控区域内的物体进行距离测量和轮廓识别.通过实验结果表明,基于OpenCV的双目立体视觉监控跟踪系统运行可靠稳定,在一定范围内达到了实验要求.

  11. 基于MATLAB与OpenCV相结合的双目立体视觉测距系统%Binocular stereo vision distance measurement system based on a combination of Matlab and OpenCV

    Institute of Scientific and Technical Information of China (English)

    汪珍珍; 赵连玉; 刘振忠

    2013-01-01

    Binocular stereo vision distance measuring technology is a hot research topic in the field of machine vision. This paper focuses on a binocular stereo vision distance measurement system based on a combination of MATLAB and OpenCV, U-sing MATLAB camera calibration, and then import the results to OpenCV for subsequent image processing and stereo matching. Camera calibration via MATLAB Calibration Toolbox has better robustness and higher precision than in the artificial calibration and OpenCV calibration. The stereo matching adopt the SAD match which is a relatively rapid and real-time regional match and able to be better applied to actual projects.%双目立体视觉测距技术是当前机器视觉领域中的一个主要研究内容.本文设计了基于MATLABatlab与OpenCV相结合的双目立体视觉测距系统,利用MATLAB进行摄像机标定后将结果导入到OpenCV进行后续的图像处理与立体匹配.摄像机标定通过MATLAB标定工具箱来完成,较于人工标定和OpenCV标定具有更好的鲁棒性和较高的精确性.立体匹配采用区域匹配中相对快速实时的SAD匹配,能够更好的被应用于工程实际.

  12. 基于双目立体视觉的西瓜子三维形态检测%Detection of Watermelon Seed Three-dimensional Shape Based on Binocular Stereo Vision

    Institute of Scientific and Technical Information of China (English)

    王士鑫; 孙涌; 余建飞; 张刚

    2012-01-01

    To improve the watermelon seed automated screening system performance, this paper presents a method of watermelon seed combination parallel binocular stereo vision and bone line to use in measurement and process the warping degree of watermeldn seed. This method uses binocular stereo vision technique for the reconstruction of three-dimensional object's surface information. The three-dimensional information is projected in space rectangular coordinates, it can obtain the seed profile in the front view and side view. The combination of Curvature Scale Space(CSS) and bone line is used in feature extraction of the side view profile of the watermelon seed. Experimental results show that the method has high recognition accuracy for warped seed.%为提高西瓜子自动筛选系统的性能,提出一种用于度量和处理西瓜子弯翘度的方法.把双目平行立体视觉与骨骼线相结合,利用双目立体视觉技术重建物体表面的三维信息.将该信息进行正交投影,分别得到西瓜子在前视图和侧视图的轮廓.利用曲率尺度空间与骨骼线相结合的方法对侧视图的瓜子轮廓进行特征提取.实验结果表明,该方法对弯翘瓜子有较高的识别精度.

  13. Clinal effects of LASIK on binocular vision in myopic anisometropia%近视性屈光参差患者LASIK术后双眼视功能评估

    Institute of Scientific and Technical Information of China (English)

    杨亮; 胡琦; 康杨; 黄磊; 王珂萌

    2012-01-01

    目的 观察近视性屈光参差患者接受准分子激光原位角膜磨镶术( LASIK)后双眼视功能的变化,探讨LASIK手术矫治近视性屈光参差对三级视功能的影响,从双眼视觉的变化评价其临床应用价值.设计前瞻性病例系列.研究对象36例(72眼)行LASIK手术的近视性屈光参差患者(双眼屈光参差≥2.50 D).方法 对36例行LASIK手术的近视性屈光参差患者分别于手术前和手术后3个月进行裸眼视力、最佳矫正视力、屈光状态和同视机双眼视功能的检测,并对双眼视功能的变化进行随访研究.主要指标手术前后裸眼视力、最佳矫正视力、屈光度、同时视、融合功能、远立体视和近立体视.结果 术前72眼的裸跟视力在0.01-0.2之间,术后3个月时均达到1.0.双跟屈光参差由术前的(5.01±1.96)D( 2.50~9.00 D),降低到术后3个月的( 0.28±0.22 )D(0.00~0.75 D).手术前后的屈光参差度的改变,差异均有显著统计学意义(P<0.01).26例屈光参差量≥2.50 D且≤6.00 D的高度屈光参差者术前戴框架眼镜下近立体视正常的12例,术后3个月增至22例,差异有统计学意义(P<0.05);16例屈光参差量>6.0D的重度屈光参差者手术前后均没有正常近立体视.术前戴框架眼镜下三级视功能(同时视、融合功能、远立体视)正常的分别为33例、18例、13例,LASIK术后3个月三级视功能正常的分别为34例、33例、23例,手术后获得融合功能和远立体视者较术前明显增加(P均<0.05).结论 LASIK矫治近视性屈光参差,不仅可提高患者裸眼视力,而且可通过减小患者双眼间的屈光差异,增加双眼物像的融合,改善立体视功能.%Objective To analyze the clinical effects on binocular vision after LASIK for myopic anisomelropia, and evaluate its clinical value in the view of vision quality. Design Prospective case series. Participants 36 cases (72 eyes) with myopic anisometropia who received

  14. Pattern adaptation of relay cells in the lateral geniculate nucleus of binocular and monocular vision-deprived cats%双眼和单眼视觉剥夺猫外膝体细胞的图形适应

    Institute of Scientific and Technical Information of China (English)

    王伟; 寿天德

    2000-01-01

    为测定丘脑外膝体细胞的图形适应是否依赖于早期视觉经验, 在细胞外记录了双眼和单眼缝合的猫外膝体中继细胞对长时间运动光栅刺激的反应. 在双眼剥夺猫,占68%的记录到的细胞在30 s内反应下降到稳定值,其平均反应值下降33%,适应程度较正常猫显著.在单眼剥夺猫,记录到的剥夺眼驱动的和非剥夺眼驱动的细胞中,分别有占53%和44%的细胞显示图形适应, 两者差别不大.研究表明, 早期视剥夺能增强或保持图形适应, 提示图形适应是外膝体细胞常见的固有性质,可能主要由遗传因素所决定.%To test whether the pattern adaptation in thalamus is dependent upon postnatal visual experience during early life, the responses of relay cells to prolonged drifting grating stimulation were recorded extracellularly from the dorsal lateral geniculate nucleus (dLGN) of cats reared with binocular and monocular lid suture. In binocular vision-deprived cats, 68% of cells recorded showed significant adaptation to prolonged grating stimuli within 30 s, with a mean response decrease of 33%, and then stabilized gradually. This adaptation was stronger than that of relay cells in normal cats. In monocular vision-deprived cats, 53% of the cells driven by the deprived eye showed similar adaptation as did 44% of the cells driven by the non-deprived eye. These results indicate that pattern adaptation could be maintained or even enhanced after visual deprivation in early life. It is suggested that pattern adaptation is a general and intrinsic property of the dLGN cells, which may be mainly determined by genetic factors.

  15. Diffuse optical intracluster light as a measure of stellar tidal stripping: The cluster CL0024+17 at z ∼ 0.4 observed at the large binocular telescope

    Energy Technology Data Exchange (ETDEWEB)

    Giallongo, E.; Menci, N.; Grazian, A.; Gallozzi, S.; Castellano, M.; Fiore, F.; Fontana, A.; Pentericci, L.; Boutsia, K.; Paris, D.; Speziali, R.; Testa, V. [INAF—Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio (Italy)

    2014-01-20

    We have evaluated the diffuse intracluster light (ICL) in the central core of the galaxy cluster CL0024+17 at z ∼ 0.4 observed with the prime focus camera (Large Binocular Camera) at the Large Binocular Telescope. The measure required an accurate removal of the galaxies' light within ∼200 kpc from the center. The residual background intensity has then been integrated in circular apertures to derive the average ICL intensity profile. The latter shows an approximate exponential decline as expected from theoretical cold dark matter models where the ICL is due to the integrated contribution of light from stars that are tidally stripped from the halo of their host galaxies due to encounters with other galaxies in the cluster cold dark matter (CDM) potential. The radial profile of the ICL over the galaxies intensity ratio (ICL fraction) is increasing with decreasing radius, but near the cluster center it starts to bend and then decreases where the overlap of the halos of the brightest cluster galaxies becomes dominant. Theoretical expectations in a simplified CDM scenario show that the ICL fraction profile can be estimated from the stripped over galaxy stellar mass ratio in the cluster. It is possible to show that the latter quantity is almost independent of the properties of the individual host galaxies but mainly depends on the average cluster properties. The predicted ICL fraction profile is thus very sensitive to the assumed CDM profile, total mass, and concentration parameter of the cluster. Adopting values very similar to those derived from the most recent lensing analysis in CL0024+17, we find a good agreement with the observed ICL fraction profile. The galaxy counts in the cluster core have then been compared with that derived from composite cluster samples in larger volumes, up to the clusters virial radius. The galaxy counts in the CL0024+17 core appear flatter and the amount of bending with respect to the average cluster galaxy counts imply a loss of

  16. Diffuse optical intracluster light as a measure of stellar tidal stripping: The cluster CL0024+17 at z ∼ 0.4 observed at the large binocular telescope

    International Nuclear Information System (INIS)

    We have evaluated the diffuse intracluster light (ICL) in the central core of the galaxy cluster CL0024+17 at z ∼ 0.4 observed with the prime focus camera (Large Binocular Camera) at the Large Binocular Telescope. The measure required an accurate removal of the galaxies' light within ∼200 kpc from the center. The residual background intensity has then been integrated in circular apertures to derive the average ICL intensity profile. The latter shows an approximate exponential decline as expected from theoretical cold dark matter models where the ICL is due to the integrated contribution of light from stars that are tidally stripped from the halo of their host galaxies due to encounters with other galaxies in the cluster cold dark matter (CDM) potential. The radial profile of the ICL over the galaxies intensity ratio (ICL fraction) is increasing with decreasing radius, but near the cluster center it starts to bend and then decreases where the overlap of the halos of the brightest cluster galaxies becomes dominant. Theoretical expectations in a simplified CDM scenario show that the ICL fraction profile can be estimated from the stripped over galaxy stellar mass ratio in the cluster. It is possible to show that the latter quantity is almost independent of the properties of the individual host galaxies but mainly depends on the average cluster properties. The predicted ICL fraction profile is thus very sensitive to the assumed CDM profile, total mass, and concentration parameter of the cluster. Adopting values very similar to those derived from the most recent lensing analysis in CL0024+17, we find a good agreement with the observed ICL fraction profile. The galaxy counts in the cluster core have then been compared with that derived from composite cluster samples in larger volumes, up to the clusters virial radius. The galaxy counts in the CL0024+17 core appear flatter and the amount of bending with respect to the average cluster galaxy counts imply a loss of

  17. 基于双目视觉的关键点的检测方法及定位研究%Study on Key Point Detection and Localization Based on Binocular Vision

    Institute of Scientific and Technical Information of China (English)

    于乃功; 马春燕; 林佳

    2011-01-01

    以双目立体视觉测量为背景,以显著性标志物中的关键点为目标,提出了基于颜色阈值分割的关键点的实时检测和定位方法;关键点的检测和定位主要分为3个过程,一是图像的预处理部分,为后续的检测和定化提供基础;二是对预处理后的图像进行关键点检测,检测的方法首先分别通过颜色阈值分割、轮廓提取、多边形逼近以及设置矩形轮廓提取出关键点所在的显著性标志物,其次根据该显著性标志物的特点,采用hough变换提取线段,并通过最小二乘法进行直线拟合,求出关键点的精确的像素坐标; 三是利用立体视觉三角测量原理,对求取的关键点进行精确的位姿计算;该方法实时性好、精度高,为后续的机器人视觉避障提供了一定的理论依据.%With the background of binocular stereo vision measurement and aiming at key point of obvious marker, a method based on color segmentation for key point detection and localization is presented. The detection and localization of key point includes three parts. The first part is image preprocessing for the following detection and localization. The second is key point detection, the detection method is through color segmentation, contour extraction, polygonal approximation, setting rectangular boundary and find the obvious marker. Then according to the feature of the obvious marker, we adopt Hough line segment detection, then fits the edge points by Lease Square Error (LSE) method, The coordinates of the key points are calculated by the equations of lines. Finally, the distance and orientation from camera to the key point is acquired accurately based on triangulation of binocular vision. The experiment result shows that the method greatly improves accuracy and real -time performance. It provides foundation for obstacle-avoidance of mobile robot .

  18. APPLICATION OF BINOCULAR VISION TECHNOLOGY IN STRUCTURAL PARTS SIZE MEASUREMENT%双目视觉技术在结构件尺寸测量中的应用

    Institute of Scientific and Technical Information of China (English)

    侯跃谦; 李冠楠; 谭庆昌

    2013-01-01

    In this paper, we discuss the engineering applications and the detection model of structural parts measurement using machine vi -sion, and propose a method to detect the size of the structural parts based on binocular vision .We use the improved solution of cameras ’ in-ternal and external parameters to calibrate the effective focal length of the single camera , and estimate the fundamental matrix by using an op-timised method in which the distance between the pixel coordinate and the corresponding epipolar line is the objective function .Through the singular value decomposition of essential matrix , rotation matrix and translation vector between two cameras are obtained .Under laboratory conditions , the space distance between two adjacent cams on same camshaft of a light vehicle is conducted practical measurement .The results show that the measurement method is able to achieve the accuracy requirement of monitoring the cam spacing in composite camshaft .%对结构件视觉测量的工程应用、检测模型进行讨论,提出一种双目视觉检测结构件空间尺寸的方法。应用改进的求解摄像机内外参数的方法对单摄像机有效焦距进行标定,应用以像素坐标到对应的极线距离为目标函数的优化方法对基本矩阵进行了估算,通过对本质矩阵的奇异值分解得到两个摄像机之间的旋转矩阵和平移向量。实验室条件下对轻型车凸轮轴凸轮间距空间尺寸进行了实际测量,结果表明,测量方法能够达到监测组合式凸轮轴凸轮间距的要求。

  19. Quantum formalism to describe binocular rivalry

    OpenAIRE

    Manousakis, Efstratios

    2007-01-01

    On the basis of the general character and operation of the process of perception, a formalism is sought to mathematically describe the subjective or abstract/mental process of perception. It is shown that the formalism of orthodox quantum theory of measurement, where the observer plays a key role, is a broader mathematical foundation which can be adopted to describe the dynamics of the subjective experience. The mathematical formalism describes the psychophysical dynamics of the subjective or...

  20. Binocular depth perception in the pigeon.

    OpenAIRE

    McFadden, S A; Wild, J. M.

    1986-01-01

    By means of a discrete-trial simultaneous discrimination procedure, pigeons were trained to respond differentially to visual arrays that were identical except that one of them contained a circle displaced in depth when viewed stereoscopically. Performance was severely disrupted when one eye was occluded. The monocular deficit was peculiar to the depth task, inasmuch as no such decrement was seen on a pattern discrimination. The results imply that presence of the displaced circle was discrimin...

  1. Enclosure rotation on the Large Binocular Telescope

    Science.gov (United States)

    Howard, James; Meeks, Robert; Ashby, David; Davison, Warren; Wiese, James; Urban, Jeff; Hansen, Rick; Schuh, Jared

    2012-09-01

    After several years of operation the enclosure rotation system of the LBT is exhibiting wear and other performance issues that may impact operations. This paper reviews the system design and assumptions used, describes the current performance and observed symptoms, and discusses recent improvements made to improve performance and reliability. The rotating enclosure of the LBT is a 2200 ton structure riding on four bogies with a total of 20 wheels. Identified deficiencies include wheel bearing capacities, bogie misalignment, and rail loading. These are partially due to excess enclosure weight, which was supposed to be 1600 tons, but also due to design errors. The most serious problem was the failure of several wheel bearings. The bearings were not designed for field serviceability, so a crash program began to determine how to replace them. This got us back on sky quickly, but a review of the engineering calculations identified an error which led to the use of undersized bearings. A method of installing a larger bearing was found, and these have been installed. One set of bogie wheels are misaligned so severely the structure makes loud popping and banging noises when the direction of building rotation changes. The bogie needs to be rotated about its vertical axis, but there was no provision in the design for this. The circular rail the bogies roll on is wearing faster than expected. The rails are extremely difficult to replace, so the short term plan is to study the problem.

  2. Numerical Simulation Which is Single Particle in the Flow of Binoculars Suffered Difference Rotational Inertia Force%双筒水流中单颗粒差异旋转惯性力的数值模拟

    Institute of Scientific and Technical Information of China (English)

    张雪宁; 牧振伟

    2015-01-01

    On the basis of the physical model experiment,using DPM model to simulate the Taylor vortex cell experiments and using Moving Mesh in binoculars and concentric rotating flow simulation,the paper discussed the motion characteristics and force law of single particles. Simulation results show that a)in the rotation system,the smaller the flow rate is,the more obvious trend of single particles centrifugal movement will be;b)When the continuous rotation of the inner cylinder,the outer cylinder is stationary,difference rotational inertia force is less than centrifugal force in numerical,but they belong to the same orders of magnitude and in the same direction,single particle do centrif-ugal movement,when the continuous rotation of the inner cylinder and then still and outer cylinder is stationary,differences in rotational iner-tia force and the centrifugal force are in the opposite direction,differences in rotational inertia force is greater than centrifugal force,both dif-fer an order of magnitude,single particle do centripetal movement;c)Whether the inner cylinder is continuous rotation or stationary after the first rotation,Reynolds gradually decrease and the radial force affects the single particle state of motion.%在实体模型试验的基础上,采用 DPM多相流模型模拟泰勒窝胞试验,并将滑移网格运用于同心双筒旋转水流模拟,对水流中单颗粒的运动进行了数值模拟,探讨了单颗粒的运动特性与受力规律。模拟结果表明:①旋转水流体系中水流速度越小,单颗粒发生离心运动的趋势越明显;②当内筒持续旋转、外筒静止时,差异旋转惯性力在数值上小于离心力,但二者属于同一个数量级且方向相同,单颗粒做离心运动,当内筒持续旋转再静止、外筒静止时,差异旋转惯性力与离心力方向相反,在数值上差异旋转惯性力大于离心力,单颗粒做向心运动;③无论内筒是持续旋转还是先旋转

  3. Características estruturais maculares de olhos de pré-escolares nascidos prematuros: análise por tomografia de coerência óptica e oftalmoscopia binocular indireta

    Directory of Open Access Journals (Sweden)

    Lígia Beatriz Bonotto

    2013-04-01

    Full Text Available OBJETIVO: Comparar a estrutura retiniana da mácula e fóvea entre prematuros com retinopatia da prematuridade (ROP estágios II e III pós-tratamento, com ROP estágios II e III regredida espontaneamente e sem ROP, através de exames de tomografia de coerência óptica (OCT e da oftalmoscopia binocular indireta (OBI. MÉTODOS: Estudo do tipo transversal, observacional e não cego. Foram incluídas crianças prematuras nascidas entre 06/1992 e 06/2006 e examinadas entre 06/2009 e 12/2010; idade gestacional menor ou igual a 32 semanas e peso ao nascer menor ou igual a 1.599 g; com mínimo de três consultas durante o período de seleção; sem retinopatia da prematuridade ou com diagnóstico de ROP estágios II ou III em pelo menos um dos olhos com regressão espontânea ou após tratamento; máximo de seis meses de idade cronológica para o primeiro exame no serviço; idade cronológica mínima de quatro anos no período da reavaliação. Foram excluídas crianças prematuras que não compareceram ou que não tinham condições clínicas para a realização dos exames de reavaliação. Os prematuros foram divididos em três grupos: G1- com ROP pós-tratamento; G2- com ROP pós-regressão espontânea; e G3- sem ROP. Os exames realizados foram OBI e OCT. RESULTADOS: Vinte e quatro prematuros (48 olhos apresentaram os critérios exigidos para a pesquisa, com idade média cronológica entre 5 e 6 anos. À OBI, houve diferença estatística significativa para a presença de alterações na retina dos prematuros do grupo G1. No entanto estas alterações corresponderam às lesões cicatriciais deixadas pelo tratamento da ROP, sem comprometimento visível da região macular. À OCT houve diferença estatística significativa para a maior espessura foveal para os prematuros do grupo G1. Considerando-se o olho esquerdo, não houve diferença estatística significativa relacionada à espessura da fóvea entre G1 e G3. Não houve diferença entre os tr

  4. 近视眼不同矫正方式的双眼视功能研究%Study of binocular function between spectacle and soft contact lens correction on myope

    Institute of Scientific and Technical Information of China (English)

    鲁智莉; 王岳秀; 于芳蕾; 殷路; 孔繁学

    2012-01-01

    [目的]探讨近视眼戴框架眼镜和角膜接触镜矫正的双眼视功能及其区别.[方法]选取近视眼63例,按习惯矫正方式分为框架眼镜矫正和角膜接触镜矫正两组,Von Graefe法测量每位近视的远、近距离水平隐斜,梯度性AC/A比率,远、近距离正、负融像性聚散,比较两组各参数差异.[结果]戴框架眼镜和角膜接触镜两组的近距离水平隐斜分别为(-7.33 ±3.67)△、(-4.12±3.35)△,AC/A比率分别为(2.69±1.78)△/D、(4.34±1.68)△/D,两组差异均有显著性意义(P<0.05),戴角膜接触镜近距离水平隐斜、AC/A比率更接近正常水平.戴角膜接触镜近距离负融像性聚散(21.32±5.12)△较戴框架眼镜组(17.14±6.03)△增大,两组差异有显著性意义(P<0.05);远距离水平隐斜,远距离正、负融像性聚散、近距离正融像性聚散两组比较差异无显著性意义(P>0.05).[结论]近视戴角膜接触镜矫正,近距离水平隐斜、AC/A比率较戴框架眼镜更接近正常值.%[ Objective ] To study the binocular function of myope with spectacle and soft contact lens and the difference between them. [Methods] Sixty -three myopes were selected in the study and divided into two groups according to the conventional correction way. Distance and near horizontal phoria, AC/A ratio, distance and near fusional vergence were measured in all subjects. [Results] Near horizontal phoria and near negative fusional vergence were ( - 7. 33 ±3. 67) , (17. 14 ±6.03)△ wearing spectacle. Those were(-4. 12 ±3. 35)△ , (21. 32 ±5. 12) △with soft contact lens , respectively. AC/A ratio were (2. 69 ± 1. 78) △/D, (4. 34 ± 1. 68) △/D in the two groups. Statistically significant differences were found with soft contact lens correction in comparison to spectacle in near horizontal phoria, AC/A ratio and near negative fusional vergence(P0. 05). [Conclusion] Soft contact lens correction in myope reduces near exophoria, increases AC/A ratio and

  5. Differences of accommodative responses between two eyes under binocular viewing condition mediated by polarizing glasses%偏光镜介导的双眼注视状态下调节反应差异性研究

    Institute of Scientific and Technical Information of China (English)

    王瑞卿; 张妍; 胡娱新; 何宇茜; 纪冬梅; 王淑荣

    2016-01-01

    variance analysis of repeated measuring and t test.RESULTS:Significant differences of accommodative responses between the two eyes were found under condition ( 1 ) and ( 2 ) at all the fixating distance. The accommodative responses in used eyes which can see the visual target were higher than in non-used eyes which cannot see the visual target ( P 0. 05).CONCLUSlON:Ciliary muscles in the used eyes were more relatively tonic than non - used eyes under binocular open viewing condition. The imbalance of accommodative responses between two eyes may be one of the risk factors resulting into the occurrence of myopia.

  6. Application of binocular vision system in nuclear power plant

    International Nuclear Information System (INIS)

    Based on stereo disparity, a vision system of locating three-dimensional position is described. The input device of the vision system is a digital camera. And special targets are used to improve the efficiency and accuracy of computer analysis. It provides a reliable and practical computer locating system for equipment maintenance in nuclear power plant

  7. On binocular vision: The geometric horopter and Cyclopean eye.

    Science.gov (United States)

    Turski, Jacek

    2016-02-01

    We study geometric properties of horopters defined by the criterion of equality of angle. Our primary goal is to derive the precise geometry for anatomically correct horopters. When eyes fixate on points along a curve in the horizontal visual plane for which the vergence remains constant, this curve is the larger arc of a circle connecting the eyes' rotation centers. This isovergence circle is known as the Vieth-Müller circle. We show that, along the isovergence circular arc, there is an infinite family of horizontal horopters formed by circular arcs connecting the nodal points. These horopters intersect at the point of symmetric convergence. We prove that the family of 3D geometric horopters consists of two perpendicular components. The first component consists of the horizontal horopters parametrized by vergence, the point of the isovergence circle, and the choice of the nodal point location. The second component is formed by straight lines parametrized by vergence. Each of these straight lines is perpendicular to the visual plane and passes through the point of symmetric convergence. Finally, we evaluate the difference between the geometric horopter and the Vieth-Müller circle for typical near fixation distances and discuss its possible significance for depth discrimination and other related functions of vision that make use of disparity processing. PMID:26548811

  8. Exploring the Moon through binoculars and small telescopes

    CERN Document Server

    Cherrington, Ernest H

    1984-01-01

    Informative, profusely illustrated guide to locating and identifying craters, rills, seas, mountains, other lunar features. Newly revised and updated with special section of new photos. Over 100 photos and diagrams. ""Extraordinary delight awaits the amateur astronomer or teacher who opens this book."" - The Science Teacher.

  9. Moirés maintained internally by binocular vision.

    Science.gov (United States)

    Piggins, D

    1978-01-01

    Moiré patterns in depth are reported when spatially periodic stimuli are viewed stereoscopically. Near-vertical square-wave gratings with horizontal disparity effected by orientation difference produce a 'venetian blind' effect. A single grating is observed divided into horizontal layers, the number of layers being a direct function of orientation difference. Lines within each layer are slanted with respect to the frontoparallel plane, becoming more so with increasing orientation difference. Subjects with stereo deficits report a decreased effect. Quantitative reports implicate stereoscopic mechanisms responsible for this unique, internal preservation of moiré patterns. PMID:740508

  10. Early Visual Responses Predict Conscious Face Perception within and between Subjects during Binocular Rivalry

    DEFF Research Database (Denmark)

    Sandberg, Kristian; Bahrami, Bahador; Kanai, Ryota;

    2013-01-01

    Previous studies indicate that conscious face perception may be related to neural activity in a large time window around 170–800 msec after stimulus presentation, yet in the majority of these studies changes in conscious experience are confounded with changes in physical stimulation. Using...... predict perception better than chance. In addition, source space analyses showed that sources in the early and late visual system predicted conscious perception more accurately than frontal and parietal sites, although conscious perception could also be decoded there. Finally, the patterns of neural...

  11. Neuronal dynamics in the visual corticothalamic pathway revealed through binocular rivalry.

    Science.gov (United States)

    Varela, F J; Singer, W

    1987-01-01

    Single unit activity was recorded from principal cells in the A-laminae of the cat dorsal lateral geniculate nucleus (dLGN). A steady state pattern of afferent activation was induced by presenting a continuously drifting square wave grating of constant spatial frequency to the eye (the dominant eye) that provided the excitatory input to the recorded cell. Intermittently, a second grating stimulus was presented to the other, nondominant, eye. In most neurones nondominant eye stimulation led to inhibition of relay cell responses. The latency of this suppressive effect was unusually long (up to 1 s) and its intensity and duration depended critically on the similarity between the gratings that were presented to the two eyes. Typically suppression was strongest when the gratings differed in orientation, direction of movement and contrast and when the nondominant eye stimulus was moving rather than stationary. Ablation of visual cortex abolished these long latency and feature-dependent interferences. We conclude that the visual cortex and the corticothalamic projections are involved in the mediation of these interocular interactions. We interpret our results as support for the hypothesis that corticothalamic feedback modifies thalamic transmission as a function of the congruency between ongoing cortical activation patterns and afferent retinal signals. PMID:3582524

  12. Geolocating thermal binoculars based on a software defined camera core incorporating HOT MCT grown by MOVPE

    Science.gov (United States)

    Pillans, Luke; Harmer, Jack; Edwards, Tim; Richardson, Lee

    2016-05-01

    Geolocation is the process of calculating a target position based on bearing and range relative to the known location of the observer. A high performance thermal imager with integrated geolocation functions is a powerful long range targeting device. Firefly is a software defined camera core incorporating a system-on-a-chip processor running the AndroidTM operating system. The processor has a range of industry standard serial interfaces which were used to interface to peripheral devices including a laser rangefinder and a digital magnetic compass. The core has built in Global Positioning System (GPS) which provides the third variable required for geolocation. The graphical capability of Firefly allowed flexibility in the design of the man-machine interface (MMI), so the finished system can give access to extensive functionality without appearing cumbersome or over-complicated to the user. This paper covers both the hardware and software design of the system, including how the camera core influenced the selection of peripheral hardware, and the MMI design process which incorporated user feedback at various stages.

  13. The search for failed supernovae with the Large Binocular Telescope: confirmation of a disappearing star

    CERN Document Server

    Adams, S M; Gerke, J R; Stanek, K Z; Dai, X

    2016-01-01

    We present Hubble Space Telescope imaging confirming the optical disappearance of the failed supernova candidate identified by Gerke et al. (2015). This $\\sim 25~M_{\\odot}$ red supergiant experienced a weak $\\sim 10^{6}~L_{\\odot}$ optical outburst in 2009 and is now at least 5 magnitudes fainter than the progenitor in the optical. The mid-IR flux has slowly decreased to the lowest levels since the first measurements in 2004. There is faint ($2000-3000~L_{\\odot}$) near-IR emission likely associated with the source. We find the late-time evolution of the source to be inconsistent with obscuration from an ejected, dusty shell. Models of the spectral energy distribution indicate that the remaining bolometric luminosity is $>6$ times fainter than that of the progenitor and is decreasing as $\\sim t^{-4/3}$. We conclude that the transient is unlikely to be a SN impostor or stellar merger. The event is consistent with the ejection of the envelope of a red supergiant in a failed supernova and the late-time emission co...

  14. Villa Binokkel Meriväljal = Villa Binoculars in Merivälja

    Index Scriptorium Estoniae

    2008-01-01

    Villa (375 m2) märgiti ära Eesti Arhitektide Liidu konkursil "Eramu 2006-2007". Arhitektid: Toomas Tammis, Inga Raukas, Tarmo Teedumäe. Sisearhitekt: Monika Löve. Projekbüroo: Arhitektuuriagentuur. Valmis: 2006. I korrus on betoonist, selle peal olev teraskarkassil osa on seest ja väljast kaetud liimitud vineertahvlitega. 3 plaani, 7 värv. välis- ja 3 sisevaadet

  15. Binocular perception of slant about oblique axes relative to a visual frame of reference

    OpenAIRE

    Van Ee, R.; Erkelens, Casper J.

    2001-01-01

    From the literature it is known that the processing of disparity for slant is different in the presence and in the absence of a visual frame of reference. We elaborate the experimental finding that vertical disparity is not processed for slant perception in the presence of a visual reference. This theoretical analysis results in a reduction of the thre basic first-order transformations between the retinal half-images (Koen derink's divergence, rotation and deformation) to only two basic ortho...

  16. Estudio de correlaciones binoculares de microtrémores y derivas

    OpenAIRE

    Roig Hernández, Ana Belén

    2012-01-01

    El ojo humano está en continuo movimiento incluso durante la fijación. Existen tres tipos de movimientos de fijación, microsacádicos, derivas y trémores. Dichos movimientos se han estudiado a lo largo de los años utilizando diferentes métodos, algunos de los cuales precisaban contacto con el ojo. Hemos desarrollado un método no invasivo para el análisis de estos movimientos utilizando secuencias grabadas con cámaras de alta velocidad. Después, usando técnicas sub-píxel realizamos un procesado...

  17. Effects of voluntary eye movement and convergence on the binocular appreciation of depth.

    Science.gov (United States)

    Foley, J. M.; Richards, W.

    1972-01-01

    Scaling techniques were employed to establish the relation between perceived distance ratio and physical distance ratio. Measurements were made both with and without free eye movement and under two states of convergence. The results were confirmed using a matching technique. With free eye movement, the perceived ratio is a monotonic increasing function of the physical ratio. Without eye movement, the perceived ratio generally increases, then decreases, as the physical ratio increases. For a given physical ratio, perceived distance ratio is less in the absence of voluntary eye movements. Convergence produces depth micropsia when eye movements are permitted, but not in their absence.

  18. Design of an Intelligent Robotic Excavator Based on Binocular Visual Recognition Technique

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin; LIU Jing; WEN Huai-xing

    2009-01-01

    Research on intelligent and robotic excavator has become a focus both at home and abroad, and this type of excavator becomes more and more important in application. In this paper, we developed a control system which can make the intelligent robotic excavator perform excavating operation autonomously. It can recognize the excava- ting targets by itself, program the operation automatically based on the original parameter, and finish all the tasks. Experimental results indicate the validity in real-time performance and precision of the control system. The intelligent robotic excavator can remarkably ease the labor intensity and enhance the working efficiency.

  19. Wavefront sensor for the Large Binocular Telescope laser guide star facility

    Science.gov (United States)

    Busoni, L.; Esposito, S.; Rabien, S.; Haug, M.; Ziegleder, J.; Hölzl, G.

    2008-07-01

    A laser guide star facility is currently being planned for the LBT. The first step of the program aims at the implementation of a ground layer adaptive optics (GLAO) system tailored on the wide-field imager / multi-object spectrograph LUCIFER having a 4x4' FoV. The current design is based on multiple Rayleigh guide stars arranged in a 2-5 arcmin angular radius constellation. A future update path toward small-field diffraction limited performances is foreseen using a hybrid system of sodium and Rayleigh beacons promising lower power requirements for the sodium laser. In this paper we present the estimated performances for both the GLAO and the hybrid implementations and we introduce the wavefront sensors opto-mechanical design . Simulations of the GLAO system show an expected gain in FWHM and encircled energy of 1.5-3 (depending on atmospheric turbulence profiles) with a FWHM variation over LUCIFER FoV below 10% and point out the role of such a GLAO system as PSF stabilizer both over the FoV and with respect to seeing temporal variations. Results of simulations for the hybrid configurations will be presented.

  20. Parallel algorithm for dominant points correspondences in robot binocular stereo vision

    Science.gov (United States)

    Al-Tammami, A.; Singh, B.

    1993-01-01

    This paper presents an algorithm to find the correspondences of points representing dominant feature in robot stereo vision. The algorithm consists of two main steps: dominant point extraction and dominant point matching. In the feature extraction phase, the algorithm utilizes the widely used Moravec Interest Operator and two other operators: the Prewitt Operator and a new operator called Gradient Angle Variance Operator. The Interest Operator in the Moravec algorithm was used to exclude featureless areas and simple edges which are oriented in the vertical, horizontal, and two diagonals. It was incorrectly detecting points on edges which are not on the four main directions (vertical, horizontal, and two diagonals). The new algorithm uses the Prewitt operator to exclude featureless areas, so that the Interest Operator is applied only on the edges to exclude simple edges and to leave interesting points. This modification speeds-up the extraction process by approximately 5 times. The Gradient Angle Variance (GAV), an operator which calculates the variance of the gradient angle in a window around the point under concern, is then applied on the interesting points to exclude the redundant ones and leave the actual dominant ones. The matching phase is performed after the extraction of the dominant points in both stereo images. The matching starts with dominant points in the left image and does a local search, looking for corresponding dominant points in the right image. The search is geometrically constrained the epipolar line of the parallel-axes stereo geometry and the maximum disparity of the application environment. If one dominant point in the right image lies in the search areas, then it is the corresponding point of the reference dominant point in the left image. A parameter provided by the GAV is thresholded and used as a rough similarity measure to select the corresponding dominant point if there is more than one point the search area. The correlation is used as a final decision tool when there is still more than one point in the search area. If there is no dominant point in the search area of if the points in the search area are below a correlation threshold, then the dominant point in the reference image is occluded and can not be corresponded. The algorithm has been modeled, implemented and shown to be fast, robust and parallel. The parallelism is created from three main features: locality of the operators; a memory optimization scheme; and the ability to fully parallelize the extraction phase which is the most computational intensive task in the algorithm. The last feature is achieved by performing the extraction phase on the two images simultaneously.

  1. Reinforcement of perceptual inference: reward and punishment alter conscious visual perception during binocular rivalry

    OpenAIRE

    Wilbertz, Gregor; van Slooten, Joanne; Sterzer, Philipp

    2014-01-01

    Perception is an inferential process, which becomes immediately evident when sensory information is conflicting or ambiguous and thus allows for more than one perceptual interpretation. Thinking the idea of perception as inference through to the end results in a blurring of boundaries between perception and action selection, as perceptual inference implies the construction of a percept as an active process. Here we therefore wondered whether perception shares a key characteristic of action se...

  2. Structural Parameter Optimization for 3-DOF Spherical Parallel Mechanism, Binocular Stereo

    OpenAIRE

    Hengyu Li; Junjie Huang; Shuping Li; Shaorong Xie; Jun Luo

    2012-01-01

    The movement scope of the human eye is proposed to be the target working space of the bionic eye by analyzing the error of 3 rotational degrees of freedom (3-DOF) Spherical Parallel Mechanism (SPM). The indexes of the worst dexterity and dynamic performance for bionic eye are defined by using the maximum condition number of Jacobian matrix. Reasonable structural parameters are chosen through analysis and comparison in the case of satisfying the special requirements of the bionic eye structure...

  3. Exploring Science Educators' Cosmological Worldviews through the Binoculars of an Argumentation Framework

    Science.gov (United States)

    Ogunniyi, M. B.

    2011-01-01

    The mandate of the new South African curriculum for educators to enact a science-indigenous knowledge curriculum in their classrooms is not only challenging to their cosmological beliefs, it is equally challenging to their instructional practices. This is because science educators (teachers) in South Africa have been schooled largely in western…

  4. On the visual system's architecture underlying binocular rivalry and motion perception

    NARCIS (Netherlands)

    Boxtel, J.J.A. van

    2008-01-01

    Our everyday visual perception is supported by a complicated set of interactions between different brain areas. These areas often have a specific function. A lot of communication takes place between, and also within, these areas. The total set of interactions between and within the different brain a

  5. Ocular dominance plasticity disrupts binocular inhibition-excitation matching in visual cortex

    NARCIS (Netherlands)

    Saiepour, M Hadi; Rajendran, Rajeev; Omrani, Azar; Ma, Wen-Pei; Tao, Huizhong W; Heimel, J Alexander; Levelt, Christiaan N

    2015-01-01

    BACKGROUND: To ensure that neuronal networks function in a stable fashion, neurons receive balanced inhibitory and excitatory inputs. In various brain regions, this balance has been found to change temporarily during plasticity. Whether changes in inhibition have an instructive or permissive role in

  6. Use of field aberrations in the alignment of the Large Binocular Telescope optics

    Science.gov (United States)

    Rakich, A.; Hill, J. M.; Biddick, C. J.; Miller, D. L.; Leibold, T.

    2008-07-01

    It is now well-known that measurement of field-aberration, and in particular the asymmetric field-astigmatism, is required to break the degeneracy of tip-induced and de-centre-induced aberration that exists when only on-axis misalignment aberrations are considered. This paper discusses the application of the measurement of field-aberrations to the alignment of LBT optics. This application ranges from the use of wide field out-of-focus images to determine corrector tip for the red and blue prime-focus correctors, to the use of data acquired by off-axis Shack-Hartman wavefront sensors to actively reposition the hexapod-mounted primary and secondary mirrors so as to simultaneously remove both de-centre and tip/tilt such that the only remaining field-astigmatism has rotational symmetry about the centre of the detector. Also introduced is a novel method to calculate the misalignment aberrations based on an extension of the plate-diagram analysis. It is shown that this method is readily applicable to the calculation of misalignment aberrations for systems of three-or-more powered mirrors, with almost no more computational difficulty than that of the two-mirror case. Results are discussed, as well as work in progress in this area.

  7. Congenital Anophthalmia and Binocular Neonatal Enucleation Differently Affect the Proteome of Primary and Secondary Visual Cortices in Mice

    Science.gov (United States)

    Smolders, Katrien; Hu, Tjing-Tjing; Bronchti, Gilles; Boire, Denis; Arckens, Lutgarde

    2016-01-01

    In blind individuals, visually deprived occipital areas are activated by non-visual stimuli. The extent of this cross-modal activation depends on the age at onset of blindness. Cross-modal inputs have access to several anatomical pathways to reactivate deprived visual areas. Ectopic cross-modal subcortical connections have been shown in anophthalmic animals but not in animals deprived of sight at a later age. Direct and indirect cross-modal cortical connections toward visual areas could also be involved, yet the number of neurons implicated is similar between blind mice and sighted controls. Changes at the axon terminal, dendritic spine or synaptic level are therefore expected upon loss of visual inputs. Here, the proteome of V1, V2M and V2L from P0-enucleated, anophthalmic and sighted mice, sharing a common genetic background (C57BL/6J x ZRDCT/An), was investigated by 2-D DIGE and Western analyses to identify molecular adaptations to enucleation and/or anophthalmia. Few proteins were differentially expressed in enucleated or anophthalmic mice in comparison to sighted mice. The loss of sight affected three pathways: metabolism, synaptic transmission and morphogenesis. Most changes were detected in V1, followed by V2M. Overall, cross-modal adaptations could be promoted in both models of early blindness but not through the exact same molecular strategy. A lower metabolic activity observed in visual areas of blind mice suggests that even if cross-modal inputs reactivate visual areas, they could remain suboptimally processed. PMID:27410964

  8. Altered GABAergic markers, increased binocularity and reduced plasticity in the visual cortex of Engrailed-2 knockout mice

    OpenAIRE

    Manuela Allegra; Yuri Bozzi

    2014-01-01

    The maturation of the GABAergic system is a crucial determinant of cortical development during early postnatal life, when sensory circuits undergo a process of activity-dependent refinement. An altered excitatory/inhibitory balance has been proposed as a possible pathogenic mechanism of autism spectrum disorders (ASD). The homeobox-containing transcription factor Engrailed-2 (En2) has been associated to ASD, and En2 knockout (En2 −/−) mice show ASD-like features accompanied by a partial loss ...

  9. An on-line calibration algorithm for external parameters of visual system based on binocular stereo cameras

    Science.gov (United States)

    Wang, Liqiang; Liu, Zhen; Zhang, Zhonghua

    2014-11-01

    Stereo vision is the key in the visual measurement, robot vision, and autonomous navigation. Before performing the system of stereo vision, it needs to calibrate the intrinsic parameters for each camera and the external parameters of the system. In engineering, the intrinsic parameters remain unchanged after calibrating cameras, and the positional relationship between the cameras could be changed because of vibration, knocks and pressures in the vicinity of the railway or motor workshops. Especially for large baselines, even minute changes in translation or rotation can affect the epipolar geometry and scene triangulation to such a degree that visual system becomes disabled. A technology including both real-time examination and on-line recalibration for the external parameters of stereo system becomes particularly important. This paper presents an on-line method for checking and recalibrating the positional relationship between stereo cameras. In epipolar geometry, the external parameters of cameras can be obtained by factorization of the fundamental matrix. Thus, it offers a method to calculate the external camera parameters without any special targets. If the intrinsic camera parameters are known, the external parameters of system can be calculated via a number of random matched points. The process is: (i) estimating the fundamental matrix via the feature point correspondences; (ii) computing the essential matrix from the fundamental matrix; (iii) obtaining the external parameters by decomposition of the essential matrix. In the step of computing the fundamental matrix, the traditional methods are sensitive to noise and cannot ensure the estimation accuracy. We consider the feature distribution situation in the actual scene images and introduce a regional weighted normalization algorithm to improve accuracy of the fundamental matrix estimation. In contrast to traditional algorithms, experiments on simulated data prove that the method improves estimation robustness and accuracy of the fundamental matrix. Finally, we take an experiment for computing the relationship of a pair of stereo cameras to demonstrate accurate performance of the algorithm.

  10. Functional MRI activity in the thalamus and occipital cortex of anesthetized dogs induced by monocular and binocular stimulation.

    OpenAIRE

    Willis, C K; Quinn, R P; McDonell, W M; Gati, J; Partlow, G; Vilis, T.

    2001-01-01

    The neuroanatomy of the mammalian visual system has received considerable attention through electrophysiological study of cats and non-human primates, and through neuroimaging of humans. Canine neuroanatomy, however, has received much less attention, limiting our understanding of canine vision and visual pathways. As an early step in applying blood oxygenation level dependant (BOLD) functional magnetic resonance imaging (fMRI) for veterinary use, we compared visual activity in the thalamus an...

  11. A high-resolution binocular video-oculography system: assessment of pupillary light reflex and detection of an early incomplete blink and an upward eye movement

    OpenAIRE

    Espinosa, Julián; Roig, Ana Belén; Pérez, Jorge; Mas, David

    2015-01-01

    Background: The pupillary light reflex characterizes the direct and consensual response of the eye to the perceived brightness of a stimulus. It has been used as indicator of both neurological and optic nerve pathologies. As with other eye reflexes, this reflex constitutes an almost instantaneous movement and is linked to activation of the same midbrain area. The latency of the pupillary light reflex is around 200 ms, although the literature also indicates that the fastest eye reflexes last 2...

  12. Binocular Goggle Augmented Imaging and Navigation System provides real-time fluorescence image guidance for tumor resection and sentinel lymph node mapping

    OpenAIRE

    Mondal, Suman B.; Shengkui Gao; Nan Zhu; Gail P. Sudlow; Kexian Liang; Avik Som; Akers, Walter J.; Fields, Ryan C.; Julie Margenthaler; Rongguang Liang; Viktor Gruev; Samuel Achilefu

    2015-01-01

    The inability to identify microscopic tumors and assess surgical margins in real-time during oncologic surgery leads to incomplete tumor removal, increases the chances of tumor recurrence, and necessitates costly repeat surgery. To overcome these challenges, we have developed a wearable goggle augmented imaging and navigation system (GAINS) that can provide accurate intraoperative visualization of tumors and sentinel lymph nodes in real-time without disrupting normal surgical workflow. GAINS ...

  13. Program Development of Calibration for Binocular Vision Based on OpenCV%基于OpenCV的双目视觉标定程序的开发

    Institute of Scientific and Technical Information of China (English)

    秦保华; 张海

    2007-01-01

    分析了基于2D标靶的摄像机标定算法原理以及双目立体视觉系统摄像机的标定方法,给出了基于开源视觉库OpenCV的摄像机标定算法的详细处理流程,实现了一个完整的摄像机标定程序,可移植到嵌入式系统中.

  14. IMPLEMENTING PASSENGER COUNTING ALGORITHM WITH BINOCULAR STEREOVISION BASED ON OPENCV%基于OpenCV实现双目视觉下的客流计数算法

    Institute of Scientific and Technical Information of China (English)

    张震; 王文娟

    2015-01-01

    为了能实时地获得公交车上的乘客数,提出一种基于OpenCV(Open Source Computer Vision Library)实现双目视觉下的客流计数算法.首先用双目摄像系统获取包含场景深度信息的视差图,然后利用Codebook背景模型与光流残差相结合的方法提取运动目标,最后采用积分投影法实现目标分割,并进行目标跟踪和计数.通过对比分析和算法测试,该算法有效克服了因计数场景中光线突变、阴影等对计数的影响,准确率达94.45%以上.

  15. Discovery of an Overdensity of Lyman-alpha Emitters Around a $\\mathrm{z}\\sim4$ QSO with the Large Binocular Telescope

    CERN Document Server

    Adams, Scott M; Croxall, Kevin V; Overzier, Roderik A; Silverman, John D

    2014-01-01

    Measurements of QSO clustering in the SDSS show that $\\mathrm{z}>4$ QSOs are some of the most highly biased objects in the universe. Their large correlation lengths of $r_0 \\sim 20h^{-1}$Mpc are comparable to the most massive clusters of galaxies in the universe today and suggest that these QSOs may mark the locations of massive cluster progenitors at high redshift. We report the discovery of an overdensity of LBGs around QSO SDSSJ114514.18+394715.9 as part of our survey to identify Lyman-Break galaxies (LBGs) around luminous $\\mathrm{z}\\sim4$ QSOs. In this field three of the eight LBGs with secure redshifts are consistent with the redshift of the QSO. We find that the likelihood that this is merely an apparent overdensity due to the chance selection of field galaxies is only 0.02%, based on comparisons to simulations and our modeled selection efficiency. Overall, our survey finds four of the 15 LBGs with secure redshifts are consistent with the redshifts of their respective QSOs, which is consistent with lum...

  16. Binocular Goggle Augmented Imaging and Navigation System provides real-time fluorescence image guidance for tumor resection and sentinel lymph node mapping

    Science.gov (United States)

    B. Mondal, Suman; Gao, Shengkui; Zhu, Nan; Sudlow, Gail P.; Liang, Kexian; Som, Avik; Akers, Walter J.; Fields, Ryan C.; Margenthaler, Julie; Liang, Rongguang; Gruev, Viktor; Achilefu, Samuel

    2015-07-01

    The inability to identify microscopic tumors and assess surgical margins in real-time during oncologic surgery leads to incomplete tumor removal, increases the chances of tumor recurrence, and necessitates costly repeat surgery. To overcome these challenges, we have developed a wearable goggle augmented imaging and navigation system (GAINS) that can provide accurate intraoperative visualization of tumors and sentinel lymph nodes in real-time without disrupting normal surgical workflow. GAINS projects both near-infrared fluorescence from tumors and the natural color images of tissue onto a head-mounted display without latency. Aided by tumor-targeted contrast agents, the system detected tumors in subcutaneous and metastatic mouse models with high accuracy (sensitivity = 100%, specificity = 98% ± 5% standard deviation). Human pilot studies in breast cancer and melanoma patients using a near-infrared dye show that the GAINS detected sentinel lymph nodes with 100% sensitivity. Clinical use of the GAINS to guide tumor resection and sentinel lymph node mapping promises to improve surgical outcomes, reduce rates of repeat surgery, and improve the accuracy of cancer staging.

  17. General Validity of Levelt's Propositions Reveals Common Computational Mechanisms for Visual Rivalry

    OpenAIRE

    P Christiaan Klink; Raymond van Ee; van Wezel, Richard J. A.

    2008-01-01

    The mechanisms underlying conscious visual perception are often studied with either binocular rivalry or perceptual rivalry stimuli. Despite existing research into both types of rivalry, it remains unclear to what extent their underlying mechanisms involve common computational rules. Computational models of binocular rivalry mechanisms are generally tested against Levelt's four propositions, describing the psychophysical relation between stimulus strength and alternation dynamics in binocular...

  18. 无人车基于双目视觉的同时定位与地图构建%Simultaneous localization and mapping for UGVs with binocular camera

    Institute of Scientific and Technical Information of China (English)

    段华旭; 闫飞; 庄严; 卜春光

    2015-01-01

    研究了无人驾驶车面向校园环境的同时定位与地图构建问题。采用双目视觉系统进行立体视觉图像匹配,并以此为基础完成优化前的位姿拓扑地图构建;采用了一种基于 ORB 图像特征和 BoW 模型的闭环检测算法,并利用时间连续性约束和几何一致性约束来提升闭环匹配正确率。位姿拓扑地图的后端优化采用了高斯-牛顿优化方法,并且在迭代过程中充分考虑了系统信息矩阵的稀疏性。利用实验室自主研发的 Smart-Cruiser 无人驾驶车平台在校园环境进行了实验,结果验证了本文所提方法的有效性和实用性。%Simultaneous localization and mapping (SLAM)problem for unmanned ground vehicles (UGVs)in campus environments was investigated.A stereo image matching algorithm was deployed to perform consistent pose estimation so that an initial pose-graph model was constructed.A loop clo-sure detection algorithm based on oriented FAST and Rotated BRIEF (ORB)feature matching and bag-of-words (BOW)model was utilized in our work,which can provide the constraints of temporal consistency and of geometrical consistency to improve the accuracy of loop closure.The back-end im-plementation for graph-based SLAM was used the Gaussian-Newton optimization method and the sparse characteristics of the system information matrix was fully utilized in the iterative procedure. The experiments were conducted on our self-developed UGV in DUT campus,and the results show the validity and robust performance of the proposed approach.

  19. 固体单颗粒在双筒同心液流中悬浮运动的试验研究%Experimental Study on Suspension Motion of Solid Single Particles in Binoculars Concentric Flow

    Institute of Scientific and Technical Information of China (English)

    马明祥; 牧振伟; 杨力行

    2014-01-01

    利用泰勒涡胞试验,采用单颗粒运动学及动力学模型,从差异旋转惯性力角度分析固体单颗粒在旋转液流两种情况下的运动特性和受力规律。试验结果表明:在内筒持续旋转、外筒始终静止水流情况下,固体单颗粒所受到的离心力绝对值大于其所受差异旋转惯性力绝对值,且离心力方向与差异旋转惯性力方向一致,固体单颗粒做离心运动,其所受的离心力数值与差异旋转惯性力数值在1个数量级左右;在内筒先旋转后静止、外筒静止的试验条件下,固体单颗粒所受到的离心力绝对值小于其所受差异旋转惯性力绝对值,且离心力方向与差异旋转惯性力方向相反,固体单颗粒做向心运动,其所受的离心力数值与差异旋转惯性力数值在同一数量级。%By using Taylor’s vortex-cell experiment and the single-particle model with kinematics and dynamics ,the mo-tion characteristics and laws of the solid single-particles under two conditions of rotary and fluid flow were analyzed from the point of different rotational inertia-force .The experimental results indicate that under the conditions of inner cylinder rotating and outer cylinder being static ,the absolute value of the solid single particles from centrifugal force is greater than that from different rotational inertia-force ,and the direction of the centrifugal force is same with that of the different rotational inertial-force ,simultaneously ,the solid single partictes do centrifugal motion ,and their centrifugal force value is about one order of magnitude with their different rotational inertia-force value ;On the contrary ,under the conditions of the inner cylinder totating firstly and then being static and the outer cylinder being static ,the obsolute value of the solid single particles from the centrifugal force is smaller than that from the different rotational inertia-force ,and the direction of the contrifugal force is contrary with that of the different rotational inertia-force ,simultaneously ,the solid single parti-cles do centripetal motion ,and their centrifugal force value is in the same order of magnitude with their different rotational inertia-force value .

  20. Research and Design of the 3D Reconstruction System Based on Binocular Stereo Vision%基于双目立体视觉三维重建系统的研究与设计

    Institute of Scientific and Technical Information of China (English)

    于勇; 张晖; 林茂松

    2009-01-01

    基于双目的立体视觉方法,介绍了一套由双工业CCD构成的立体视觉系统,设计了一套切实可行的三维重建系统方案,其中包括图像获取模块,基于OpenCV的摄像机标定系统,SIFT算法实现特征点提取与立体匹配,深度信息计算,OpenGL三维模型重构几大模块.系统各模块经过试验测试和验证,能够通过两幅图像恢复出物体三维可见表面几何形状,充分发挥了OpenCV函数库的功能,基本上能满足三维重建目标的要求,尤其对城市景观的三维重建有较大应用价值.

  1. Quality Index for Stereoscopic Images by Separately Evaluating Adding and Subtracting.

    Directory of Open Access Journals (Sweden)

    Jiachen Yang

    Full Text Available The human visual system (HVS plays an important role in stereo image quality perception. Therefore, it has aroused many people's interest in how to take advantage of the knowledge of the visual perception in image quality assessment models. This paper proposes a full-reference metric for quality assessment of stereoscopic images based on the binocular difference channel and binocular summation channel. For a stereo pair, the binocular summation map and binocular difference map are computed first by adding and subtracting the left image and right image. Then the binocular summation is decoupled into two parts, namely additive impairments and detail losses. The quality of binocular summation is obtained as the adaptive combination of the quality of detail losses and additive impairments. The quality of binocular summation is computed by using the Contrast Sensitivity Function (CSF and weighted multi-scale (MS-SSIM. Finally, the quality of binocular summation and binocular difference is integrated into an overall quality index. The experimental results indicate that compared with existing metrics, the proposed metric is highly consistent with the subjective quality assessment and is a robust measure. The result have also indirectly proved hypothesis of the existence of binocular summation and binocular difference channels.

  2. Monocular viewing prolongs reversal interval of perceptual rival figure

    Science.gov (United States)

    Tanahashi, Shigehito; Segawa, Kaori; Zheng, Meihong; Kuze, Junko; Ukai, Kazuhiko

    2012-09-01

    The authors examined whether the perceptual reversal rate changes under monocular versus binocular viewing conditions. Our results suggest that the perceptual reversal interval increases during monocular viewing. The ratio of the reversal rate (1/interval) for the two viewing conditions (binocular/monocular) was 1.28 over a wide range of pattern luminance levels. The quoted ratio was 1.40 when the luminance was high. Such a ratio parallels the value of a well-known binocular summation index (sqrt 2 ), which was derived from the signal detection theory. The binocular summation index shows that the strength of an input signal is enhanced by binocular viewing. However, how the binocular summation shortens the perceptual reversal interval is unclear. This issue can be resolved if the perceptual reversal is derived by integrating the strength of an unconscious image signal. Thus, we discussed the mechanism of perceptual switch by associating two classical, well-studied phenomena, binocular summation and perceptual switch.

  3. Owls see in stereo much like humans do

    OpenAIRE

    Willigen, R.F. van der

    2011-01-01

    While 3D experiences through binocular disparity sensitivity have acquired special status in the understanding of human stereo vision, much remains to be learned about how binocularity is put to use in animals. The owl provides an exceptional model to study stereo vision as it displays one of the highest degrees of binocular specialization throughout the animal kingdom. In a series of six behavioral experiments, equivalent to hallmark human psychophysical studies, I compiled an extensive body...

  4. Helmet-Mounted Displays (HMD)

    Data.gov (United States)

    Federal Laboratory Consortium — The Helmet-Mounted Display labis responsible for monocular HMD day display evaluations; monocular HMD night vision performance processes; binocular HMD day display...

  5. Active robot vision camera heads, model based navigation and reactive control

    CERN Document Server

    Christensen, H I; Bunke, H

    1993-01-01

    One of the series in Machine Perception and Artificial Intelligence, this book covers subjects including the Harvard binocular head; heads, eyes, and head-eye systems; a binocular robot head with torsional eye movements; and escape and dodging behaviours for reactive control.

  6. Owls see in stereo much like humans do

    NARCIS (Netherlands)

    Willigen, R.F. van der

    2011-01-01

    While 3D experiences through binocular disparity sensitivity have acquired special status in the understanding of human stereo vision, much remains to be learned about how binocularity is put to use in animals. The owl provides an exceptional model to study stereo vision as it displays one of the hi

  7. Are the neural correlates of conscious contents stable or plastic?

    DEFF Research Database (Denmark)

    Sandberg, Kristian; Overgaard, Morten; Rees, Geraint

    2012-01-01

    examine the second assumption. We recorded the magnetoencephalographic (MEG) signal from healthy human participants while they viewed an intermittently presented binocular rivalry stimulus consisting of a face and a grating. During binocular rivalry, the stimulus is kept constant, but the conscious...

  8. RR Lyrae stars in the Andromeda satellite galaxies

    Science.gov (United States)

    Cusano, F.; Garofalo, A.; Clementini, G.

    2016-05-01

    In this contribution we summarize results on the search for variable stars and the study of the resolved stellar populations in four dwarf spheroidal satellites of the Andromeda galaxy that we have observed with the Large Binocular Cameras (LBC) at the Large Binocular Telescope (LBT).

  9. The sensitivity of schlieren systems for viewing ultrasound

    International Nuclear Information System (INIS)

    A novel set of simplifying assumptions makes computer prediction of schlieren sensitivity possible economically. Predictions correlate with experimental and published figures. Other means of improving sensitivity are given. A compact schlieren system giving binocular stereoscopic viewing is described

  10. Augmented Reality in a Simulated Tower Environment: Effect of Field of View on Aircraft Detection

    Science.gov (United States)

    Ellis, Stephen R.; Adelstein, Bernard D.; Reisman, Ronald J.; Schmidt-Ott, Joelle R.; Gips, Jonathan; Krozel, Jimmy; Cohen, Malcolm (Technical Monitor)

    2002-01-01

    An optical see-through, augmented reality display was used to study subjects' ability to detect aircraft maneuvering and landing at the Dallas Ft. Worth International airport in an ATC Tower simulation. Subjects monitored the traffic patterns as if from the airport's western control tower. Three binocular fields of view (14 deg, 28 deg and 47 deg) were studied in an independent groups' design to measure the degradation in detection performance associated with the visual field restrictions. In a second experiment the 14 deg and 28 deg fields were presented either with 46% binocular overlap or 100% overlap for separate groups. The near asymptotic results of the first experiment suggest that binocular fields of view much greater than 47% are unlikely to dramatically improve performance; and those of the second experiment suggest that partial binocular overlap is feasible for augmented reality displays such as may be used for ATC tower applications.

  11. Seasonal variations in heavy mineral placer sand from Kalbadevi Bay, Ratnagiri, Maharashtra

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    . The sand, silt and clay contents were determined by pipette analysis after Folk (1968). Heavy mineral content was determined by counting average 1000 grains (fractions) randomly under binocular microscope. Fig. 1. Near shore sampling profiles...

  12. General validity of Levelt's propositions reveals common computational mechanisms for visual rivalry

    NARCIS (Netherlands)

    Klink, P.C.; van Ee, R.; van Wezel, R.J.A.

    2008-01-01

    The mechanisms underlying conscious visual perception are often studied with either binocular rivalry or perceptual rivalry stimuli. Despite existing research into both types of rivalry, it remains unclear to what extent their underlying mechanisms involve common computational rules. Computational m

  13. 76 FR 26255 - Takes of Marine Mammals Incidental to Specified Activities; Marine Geophysical Survey in the...

    Science.gov (United States)

    2011-05-06

    ...), when required. Laser range-finding binoculars (Leica LRF 1200 laser rangefinder or equivalent) will be...., unidentified dolphin, sperm whale), types and nature of sounds heard (e.g., clicks, continuous,...

  14. Pleoptic and orthoptic training for visually impaired children in preschool age.

    OpenAIRE

    ŠTOČKOVÁ, Šárka

    2009-01-01

    The theoretical part of this bachelor's paper is aimed at the development of visual perception since the child{\\crq}s birth until pre-school age, and further at pleoptic and orthoptic training. The paper also mentions the anatomy of the organ of vision, and the eyesight impairments of childhood. The theoretical part examines in more detail binocular vision, as pleoptic and orthoptic training are aimed exactly at binocular vision impairments (strabismus and amblyopia). The practical part prese...

  15. Disparity energy model using a trained neuronal population

    OpenAIRE

    Martins, Jaime A.; Rodrigues, J. M. F.; du Buf, J. M. H.

    2011-01-01

    Depth information using the biological Disparity Energy Model can be obtained by using a population of complex cells. This model explicitly involves cell parameters like their spatial frequency, orientation, binocular phase and position difference. However, this is a mathematical model. Our brain does not have access to such parameters, it can only exploit responses. Therefore, we use a new model for encoding disparity information implicitly by employing a trained binocular ...

  16. Visual control in children with developmental dyslexia Controle visual em crianças com dislexia do desenvolvimento

    OpenAIRE

    Stella Maris Costa Castro; Cintia Alves Salgado; Fernando Portolani Andrade; Sylvia Maria Ciasca; Keila Miriam Monteiro de Carvalho

    2008-01-01

    PURPOSE: To assess binocular control in children with dyslexia. METHODS: Cross-sectional study with 26 children who were submitted to a set of ophthalmologic and visual tests. RESULTS: In the dyslexic children less eye movement control in voluntary convergence and unstable binocular fixation was observed. CONCLUSION: The results support the hypothesis that developmental dyslexia might present deficits which involve the magnocellular pathway and a part of the posterior cortical attentional net...

  17. Light-weight Monocular 3D Display Unit Using Polypyrrole Linear Actuator

    OpenAIRE

    Kodama, Yuuki; Sakamoto, Kunio

    2010-01-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. We have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its lin...

  18. Temporal events in cyclopean vision.

    OpenAIRE

    Andrews, T J; White, L. E; Binder, D; Purves, D.

    1996-01-01

    The majority of neurons in the primary visual cortex of primates can be activated by stimulation of either eye; moreover, the monocular receptive fields of such neurons are located in about the same region of visual space. These well-known facts imply that binocular convergence in visual cortex can explain our cyclopean view of the world. To test the adequacy of this assumption, we examined how human subjects integrate binocular events in time. Light flashes presented synchronously to both ey...

  19. Anatomical Origins of Ocular Dominance in Mouse Primary Visual Cortex

    OpenAIRE

    Coleman, Jason E.; Law, Karen; Bear, Mark F.

    2009-01-01

    Ocular dominance (OD) plasticity is a classic paradigm for studying the effect of experience and deprivation on cortical development, and is manifested as shifts in the relative strength of binocular inputs to primary visual cortex (V1). The mouse has become an increasingly popular model for mechanistic studies of OD plasticity and, consequently, it is important that we understand how binocularity is constructed in this species. One puzzling feature of the mouse visual system is the gross dis...

  20. Dynamics of the near response under natural viewing conditions with an open-view sensor

    OpenAIRE

    Chirre, Emmanuel; Prieto, Pedro; Artal, Pablo

    2015-01-01

    We have studied the temporal dynamics of the near response (accommodation, convergence and pupil constriction) in healthy subjects when accommodation was performed under natural binocular and monocular viewing conditions. A binocular open-view multi-sensor based on an invisible infrared Hartmann-Shack sensor was used for non-invasive measurements of both eyes simultaneously in real time at 25Hz. Response times for each process under different conditions were measured. The accommodative respon...

  1. "X-ray vision" and the evolution of forward-facing eyes

    OpenAIRE

    Changizi, Mark A.; Shimojo, Shinsuke

    2008-01-01

    Why do our eyes face forward, and why do many mammals have eyes facing sideways? Here, we describe results suggesting that the degree of binocular convergence is selected to maximize how much the mammal can see in its environment. Mammals in non-cluttered environments can see the most around them with panoramic, laterally directed eyes. Mammals in cluttered environments, however, can see best when their eyes face forward, for binocularity has the power of "seeing through" clutter out in the w...

  2. Persistent behavioural blindness after early visual deprivation and active visual rehabilitation: a case report.

    OpenAIRE

    S Carlson; Hyvärinen, L; Raninen, A.,

    1986-01-01

    Early long lasting binocular deprivation results in behavioural blindness in both man and experimental animals. However, few reported cases show that visual rehabilitation may improve visual behaviour. A 34-year-old man who had experienced 30 years of binocular deprivation due to bilateral cataracts received visual rehabilitation for one year. The rehabilitation included training in eye-hand co-ordination, recognition of objects, evaluation of distance and size, and mobility training. Despite...

  3. Reduced Perceptual Exclusivity during Object and Grating Rivalry in Autism

    OpenAIRE

    Freyberg, J.; Robertson, C.E.; Baron-Cohen, S

    2015-01-01

    Background: The dynamics of binocular rivalry may be a behavioural footprint of excitatory and inhibitory neural transmission in visual cortex. Given the presence of atypical visual features in Autism Spectrum Conditions (ASC), and evidence in support of the idea of an imbalance in excitatory/inhibitory neural transmission in ASC, we hypothesized that binocular rivalry might prove a simple behavioural marker of such a transmission imbalance in the autistic brain. In support of this hypothesis...

  4. Presence of Fusion in Albinism after Strabismus Surgery Augmented with Botulinum Toxin (Type A) Injection

    OpenAIRE

    Tavakolizadeh, Sepideh; Farahi, Azadeh

    2013-01-01

    It is commonly accepted that albino patients with strabismus rarely achieve binocularity and depth perception after strabismus surgery. The presence of retino-geniculo-cortical misrouting, a hallmark of the visual system in albinism, does not necessarily cause total loss of binocular vision, however, not even in albino patients with strabismus. Recently some degrees of stereopsis were reported in albinism patients with minimal clinical nystagmus, if any, in the absence of strabismus. It is po...

  5. Intraexaminer repeatability and agreement in stereoacuity measurements made in young adults

    Institute of Scientific and Technical Information of China (English)

    Beatriz; Antona; Ana; Barrio; Isabel; Sanchez; Enrique; Gonzalez; Guadalupe; Gonzalez

    2015-01-01

    AIM: To determine the repeatability and agreement of stereoacuity measurements made using some of the most widely used clinical tests: Frisby, TNO, Randot and Titmus.METHODS: Stereoacuity was measured in two different sessions separated by a time interval of at least 24 h but no longer than 1wk in 74 subjects of mean age 20.6y using the four methods. The study participants were divided into two groups: subjects with normal binocular vision and subjects with abnormal binocular vision.RESULTS: Best repeatability was shown by the Frisby and Titmus [coefficient of repeatability(COR): ±13 and±12s arc respectively] in the subjects with normal binocular vision though a clear ceiling effect was noted.In the subjects with abnormal binocular vision, best repeatability was shown by the Frisby(COR: ±69s arc)and Randot(COR: ±72s arc). In both groups, the TNO test showed poorest agreement with the other tests.CONCLUSION:Therepeatabilityofstereoacuitymeasures was low in subjects with poor binocular vision yet fairly good in subjects with normal binocular vision with the exception of the TNO test. The reduced agreement detected between the tests indicates they cannot be used interchangeably.

  6. Intraexaminer repeatability and agreement in stereoacuity measurements made in young adults

    Directory of Open Access Journals (Sweden)

    Beatriz Antona

    2015-04-01

    Full Text Available AIM: To determine the repeatability and agreement of stereoacuity measurements made using some of the most widely used clinical tests: Frisby, TNO, Randot and Titmus. METHODS: Stereoacuity was measured in two different sessions separated by a time interval of at least 24h but no longer than 1wk in 74 subjects of mean age 20.6y using the four methods. The study participants were divided into two groups: subjects with normal binocular vision and subjects with abnormal binocular vision. RESULTS: Best repeatability was shown by the Frisby and Titmus [coefficient of repeatability (COR: ±13 and ±12s arc respectively] in the subjects with normal binocular vision though a clear ceiling effect was noted. In the subjects with abnormal binocular vision, best repeatability was shown by the Frisby (COR: ±69s arc and Randot (COR: ±72s arc. In both groups, the TNO test showed poorest agreement with the other tests. CONCLUSION: The repeatability of stereoacuity measures was low in subjects with poor binocular vision yet fairly good in subjects with normal binocular vision with the exception of the TNO test. The reduced agreement detected between the tests indicates they cannot be used interchangeably.

  7. Effects of bilateral and unilateral laser ocular exposure in humans

    Science.gov (United States)

    Stamper, David A.; Lund, David J.; Molchany, Jerome W.; Stuck, Bruce E.

    2003-06-01

    INTRODUCTION: The amount of visual disruption experienced by individuals exposed to a visible laser source at levels, which are below that, which will damage the cornea or retina will depend on laser exposure parameters and task demands. Previous work has evaluated the effects of wavelength, duration, ambient light level, and target variables. One factor that has not received attention is monocular vs. binocular exposure. Whether the exposure is monocular or binocular may alter pupil dynamics, eyelid closure, and ultimately affect visual performance. METHODS: In this study 10 males and females were exposed to 0.1 and 3.0 sec laser flashes while tracking a dynamic target at 0.28 deg/sec through a scope that was capable of selecting binocular or monocular viewing. Bright (430 nits) and dawn/dusk (4.3 nits) ambient light conditions were simulated using ND filters. A collimated 514.5 nm argon laser beam produced corneal radiant exposures of 0.16 and 1.0 mJ/cm2 for the 0.1 and 3.0 sec conditions respectively. For each flash trial total time off target and maximum absolute error scores were calculated. Eye response (changes in pupil diameter) was assessed by evaluation of videotape from an IR eye camera. Tracking error scores (total time off target) were calculated for each flash trial. RESULTS: Analysis of variance results for the total time off target scores found all three main factors (light level, exposure duration, and monocular/binocular to be significant. Earlier studies have previously shown dawn/dusk flash exposures be more disruptive than bright light trials. Also three sec exposures were more disruptive than one sec exposures. Finally, monocular exposures produced significantly higher error scores than did binocular exposures. For the pupil diameters the post-flash diameters were significantly smaller that the pre-flash diameters and monocular diameters larger that binocular pupil sizes. SUMMARY: The Total Time Off Target error scores for the monocular

  8. Adaptive optofluidic lens(es) for switchable 2D and 3D imaging

    Science.gov (United States)

    Huang, Hanyang; Wei, Kang; Zhao, Yi

    2016-03-01

    The stereoscopic image is often captured using dual cameras arranged side-by-side and optical path switching systems such as two separate solid lenses or biprism/mirrors. The miniaturization of the overall size of current stereoscopic devices down to several millimeters is at a sacrifice of further device size shrinkage. The limited light entry worsens the final image resolution and brightness. It is known that optofluidics offer good re-configurability for imaging systems. Leveraging this technique, we report a reconfigurable optofluidic system whose optical layout can be swapped between a singlet lens with 10 mm in diameter and a pair of binocular lenses with each lens of 3 mm in diameter for switchable two-dimensional (2D) and three-dimensional (3D) imaging. The singlet and the binoculars share the same optical path and the same imaging sensor. The singlet acquires a 3D image with better resolution and brightness, while the binoculars capture stereoscopic image pairs for 3D vision and depth perception. The focusing power tuning capability of the singlet and the binoculars enable image acquisition at varied object planes by adjusting the hydrostatic pressure across the lens membrane. The vari-focal singlet and binoculars thus work interchangeably and complementarily. The device is thus expected to have applications in robotic vision, stereoscopy, laparoendoscopy and miniaturized zoom lens system.

  9. Effects of different types of refractive errors on bilateral amblyopia

    Directory of Open Access Journals (Sweden)

    Mücella Arıkan Yorgun

    2012-12-01

    Full Text Available Objectives: Identifying effects of different types of refractiveerrors on final visual acuity and stereopsis levels inpatients with bilateral amblyopia.Materials and methods: Patients with bilateral amblyopialower than ≥1.5 D anisometropia were included. Thepatients were classified according to the level of sphericalequivalent (0-4 D and >4 D of hypermetropia, the levelof astigmatism (below and above 2D in positive cylinderand type of composed refractive error [ 4 D of hypermetropiaand 2 D of astigmatism (group III]. Initialand final binocular best corrected visual acuities (BCVAwere compared between groups.Results: The initial binocular BCVA levels were significantlylower in patients with > 4 D of hypermetropia(p=0.028, without correction after treatment (p=0.235.The initial binocular BCVA was not different betweenastigmatism groups, but final BCVA levels were significantlylower in 4-6D of astigmatism compared with 2-4D of astigmatism (p=0.001. During comparison of composedrefractive errors, only the initial binocular BCVAwas significantly lower in group I compared to group II(p=0.015. The final binocular BCVA levels were not differentbetween groups I and III (p>0.05.Conclusions: Although the initial BCVA is lower in patientswith higher levels of hypermetropia, the response ofpatients to treatment with glasses is good. The responseof patients with high levels of astigmatism seems to belimited. J Clin Exp Invest 2012; 3(4: 467-471Key words: Amblyopia, isoametropic amblyopia, hypermetropia,refractive amblyopia, visual acuity

  10. Two independent mechanisms for motion-in-depth perception: evidence from individual differences

    Directory of Open Access Journals (Sweden)

    Harold T Nefs

    2010-10-01

    Full Text Available Our forward-facing eyes allow us the advantage of binocular visual information: using the tiny differences between right and left eye views to learn about depth and location in three dimensions. Our visual systems also contain specialized mechanisms to detect motion-in-depth from binocular vision, but the nature of these mechanisms remains controversial. Binocular motion-in-depth perception could theoretically be based on first detecting binocular disparity and then monitoring how it changes over time. The alternative is to monitor the motion in the right and left eye separately and then compare these motion signals. Here we used an individual differences approach to test whether the two sources of information are processed via dissociated mechanisms, and to measure the relative importance of those mechanisms. Our results suggest the existence of two distinct mechanisms, each contributing to the perception of motion in depth in most observers. Additionally, for the first time, we demonstrate the relative prevalence of the two mechanisms within a normal population. In general, visual systems appear to rely mostly on the mechanism sensitive to changing binocular disparity, but perception of motion in depth is augmented by the presence of a less sensitive mechanism that uses interocular velocity differences. Occasionally, we find observers with the opposite pattern of sensitivity. More generally this work showcases the power of the individual differences approach in studying the functional organisation of cognitive systems.

  11. Electrothermal MEMS parallel plate rotation for single-imager stereoscopic endoscopes.

    Science.gov (United States)

    Jang, Kyung-Won; Yang, Sung-Pyo; Baek, Seung-Hwan; Lee, Min-Suk; Park, Hyeon-Cheol; Seo, Yeong-Hyeon; Kim, Min H; Jeong, Ki-Hun

    2016-05-01

    This work reports electrothermal MEMS parallel plate-rotation (PPR) for a single-imager based stereoscopic endoscope. A thin optical plate was directly connected to an electrothermal MEMS microactuator with bimorph structures of thin silicon and aluminum layers. The fabricated MEMS PPR device precisely rotates an transparent optical plate up to 37° prior to an endoscopic camera and creates the binocular disparities, comparable to those from binocular cameras with a baseline distance over 100 μm. The anaglyph 3D images and disparity maps were successfully achieved by extracting the local binocular disparities from two optical images captured at the relative positions. The physical volume of MEMS PPR is well fit in 3.4 mm x 3.3 mm x 1 mm. This method provides a new direction for compact stereoscopic 3D endoscopic imaging systems. PMID:27137580

  12. Automatic Convergence Adjustment for Stereoscopy using Eye Tracking

    DEFF Research Database (Denmark)

    Fisker, Martin; Gram, Kristoffer; Kronborg Thomsen, Kasper; Vasilarou, Dimitra; Kraus, Martin

    When using stereoscopic displays, decoupling between convergence and accommodation can cause eyestrain. This paper proposes an adjustment method to automatically fit convergence at user fixation depth to accommodation by using eye tracking. Two different adjustment methods are proposed: one...... binocular, adjusting the images for both eyes, and one monocular, which adjusts only the image for the non-dominant eye. Preliminary results suggest better user comfort and a preference for binocular adjustment in high adjustment scenarios, while the adjustment is less noticeable with the monocular system....

  13. Calibration for 3D Structured Light Measurement

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A calibration procedure was developed for three-dimensional(3D) binocular structured light measurement systems. In virtue of a specially designed pattern, matching points in stereo images are extracted. And then sufficient 3D space points are obtained through pairs of images with the intrinsic and extrinsic parameters of each camera estimated prior and consequently some lights are calibrated by means of multi point fitting. Finally, a mathematical model is applied to interpolate and approximate all dynamic scanning lights based on geometry. The process of calibration method is successfully used in the binocular 3D measurement system based on structured lights and the 3D reconstruction results are satisfying.

  14. Oculomotricidade e seus fundamentos

    OpenAIRE

    Bicas Harley E. A.

    2003-01-01

    Partindo-se de um circuito esquemático relacionando os sistemas sensorial (visual binocular) e oculomotor, cujos defeitos em vias aferentes ou eferentes, ou de suas interações, explicam o aparecimento dos estrabismos e suas conseqüências, são examinados os fundamentos e referenciais da movimentação ocular. Apresentam-se os conceitos de eixos e planos, centro de massa e de rotação, definem-se os movimentos monoculares de translação e de rotação e os binoculares de versões e vergências. É també...

  15. Oculomotricidade e seus fundamentos Ocular motility: foundations

    OpenAIRE

    Harley E. A. Bicas

    2003-01-01

    Partindo-se de um circuito esquemático relacionando os sistemas sensorial (visual binocular) e oculomotor, cujos defeitos em vias aferentes ou eferentes, ou de suas interações, explicam o aparecimento dos estrabismos e suas conseqüências, são examinados os fundamentos e referenciais da movimentação ocular. Apresentam-se os conceitos de eixos e planos, centro de massa e de rotação, definem-se os movimentos monoculares de translação e de rotação e os binoculares de versões e vergências. É també...

  16. Negative “gossip” stimuli modulate left-lateralized P1 component while viewing neutral faces

    DEFF Research Database (Denmark)

    Weed, Ethan; Allen, Micah Galen; Gramm, Daniel

    Language allows us to operate more efficiently in the world. By hearing about others’ experiences, we are able to orient toward things that could be beneficial to us, and avoid hazards. This sharing of experiences is particularly prominent in the social realm. Using a binocular rivalry paradigm......, Anderson et al. (2011) showed that short “gossip” phrases modulated the length of time faces remained perceptually dominant. However, binocular rivalry is measured by self-report. We used EEG to investigate the timing of gossip’s early effect on face perception. Gossip stimuli were those used by Anderson...

  17. Sensory exotropia subsequent to senile cataract

    Institute of Scientific and Technical Information of China (English)

    LOU Ding-hua; XU Ye-sheng; LI Yu-min

    2005-01-01

    To evaluate the phacoemulsification and intraocular lens implantation in patients with sensory exotropia subsequent to senile cataract. The authors prospectively studied the role of phacoemulsification and intraocular lens implantation on 25 patients by observing visual acuity, ocular alignment, binocular vision and diplopia pre-, 1 month post- and 3 months post-operation. The patients underwent follow-up for three months. Postoperatively, one patient had a corrected visual acuity of 20/50, and 24 patients had 20/40 or better. The ocular alignment, binocular vision and diplopia were resolved spontaneously. Phacoemulsification and intraocular lens implantation performed together is effective on sensory exotropia subsequent to senile cataract.

  18. Control & competition square off for primacy in the uranium market

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-06-01

    Who dominates? Who competes? How level is the playing field? And how free is the free market? Of more than academic interest, these questions are being thrashed out by a bevy of market participants. But resolution is no dainty game of croquet; it looks more like a rugby scrum. So grab your binoculars and let the games begin.

  19. Dating the Moon: Teaching Lunar Stratigraphy and the Nature of Science

    Science.gov (United States)

    Murphy, Edward; Bell, Randy

    2013-01-01

    As our closest celestial neighbor, the Moon is a familiar and inspiring object to investigate using a small telescope, binoculars, or even photographs or one of the many high quality maps available online. The wondrously varied surface of the Moon--filled with craters, mountains, volcanic flows, scarps, and rilles--makes the Moon an excellent…

  20. Artificial pupil versus contralateral balanced contact lens fit for presbyopia correction

    Directory of Open Access Journals (Sweden)

    Santiago García-Lázaro

    2014-04-01

    Full Text Available Purpose: To assess and compare the effects of contact lens-based artificial pupil design and contralateral balanced multifocal contact lens combination (CBMCLC on visual performance. Methods: This randomized crossover study conducted at the University of Valencia, Spain included 38 presbyopic patients using an artificial pupil contact lens in the nondominant eye and a CBMCLC. After a month of lens wear, the binocular distance visual acuity (BDVA, binocular near visual acuity (BNVA, defocus curve, binocular distance, and near contrast sensitivity and near stereoacuity (NSA were measured under photopic conditions (85 cd/m2. Moreover, BDVA and binocular distance contrast sensitivity were examined under mesopic conditions (5 cd/m2. Results: Visual acuity at an intermediate distance and near vision was better with the CBMCLC than with the artificial pupil (p<0.05. Statistically significant differences were found in contrast sensitivity between the two types of correction for distance (under mesopic conditions and for near vision, with the CBMCLC exhibiting better results in both cases (p<0.05. The mean NSA values obtained for the artificial pupil contact lens were significantly worse than those for the CBMCLC (p=0.001. Conclusion: The CBMCLC provided greater visual performance in terms of intermediate and near vision compared with the artificial pupil contact lens.

  1. Adult Visual Experience Promotes Recovery of Primary Visual Cortex from Long-Term Monocular Deprivation

    Science.gov (United States)

    Fischer, Quentin S.; Aleem, Salman; Zhou, Hongyi; Pham, Tony A.

    2007-01-01

    Prolonged visual deprivation from early childhood to maturity is believed to cause permanent visual impairment. However, there have been case reports of substantial improvement of binocular vision in human adults following lifelong visual impairment or deprivation. These observations, together with recent findings of adult ocular dominance…

  2. Comparison of Dynamic Visual Acuity between Water Polo Players and Sedentary Students

    Science.gov (United States)

    Quevedo-Junyent, Lluisa; Aznar-Casanova, Jose Antonio; Merindano-Encina, Dolores; Cardona, Genis; Sole-Forto, Joan

    2011-01-01

    In this study, we examined differences in dynamic visual acuity between elite and subelite water polo players and sedentary students. To measure dynamic visual acuity binocularly, we asked participants to indicate the orientation of a broken ring, similar to the Landolt C, which increased in size as it moved across a computer screen. Two different…

  3. Visual control in children with developmental dyslexia Controle visual em crianças com dislexia do desenvolvimento

    Directory of Open Access Journals (Sweden)

    Stella Maris Costa Castro

    2008-12-01

    Full Text Available PURPOSE: To assess binocular control in children with dyslexia. METHODS: Cross-sectional study with 26 children who were submitted to a set of ophthalmologic and visual tests. RESULTS: In the dyslexic children less eye movement control in voluntary convergence and unstable binocular fixation was observed. CONCLUSION: The results support the hypothesis that developmental dyslexia might present deficits which involve the magnocellular pathway and a part of the posterior cortical attentional network.OBJETIVO: Avaliar o controle binocular em crianças com dislexia. MÉTODOS: Estudo transversal do qual participaram 26 crianças, nas quais foram aplicadas uma série de exames oftalmológicos e visuais. RESULTADOS: Nas crianças com dislexia observou-se controle menor na convergência voluntária e na estabilidade da fixação binocular. CONCLUSÃO: Os resultados apóiam a hipótese de que na dislexia do desenvolvimento podem ocorrer déficits que envolvem a via visual magnocelular e uma parte da rede cortical posterior da atenção.

  4. What a Football Fan

    Institute of Scientific and Technical Information of China (English)

    王保安; 孙鹏

    2004-01-01

    While the football fan was thrilled to be at the Super Bowl, he was disappointed with the location of his seat. Peering across the stadium through his binoculars, he spied an empty seat on the 50-yard line and made his way there.

  5. Chondrule-like object from the Indian Ocean cosmic spherules

    Digital Repository Service at National Institute of Oceanography (India)

    Reshma, K.; Rudraswami, N.G.; ShyamPrasad, M.

    sediment samples (total weight of sediment sieved – 164 kg wet weight) using the binocular micro- scope. All the spherules were mounted in plastic and were polished. The spherules were observed in JEOL JSM5800LV Scanning Electron Microscope (SEM) and images...

  6. Refraction and visual acuity in a national Danish cohort of 4-year-old children of extremely preterm delivery

    DEFF Research Database (Denmark)

    Fledelius, Hans C; Bangsgaard, Regitze; Slidsborg, Carina; laCour, Morten

    2015-01-01

    refractive distribution presented a myopic tail (4.5%) and a hyperopic tail (11.9% ≥+2.5 D) as special preterm features, and corneas were more curved. Astigmatism and anisometropia were only marginally increased, and visual acuities were generally good. Best-corrected binocular median logMAR visual acuity...

  7. General validity of Levelt's propositions reveals common computational mechanisms for visual rivalry.

    Directory of Open Access Journals (Sweden)

    P Christiaan Klink

    Full Text Available The mechanisms underlying conscious visual perception are often studied with either binocular rivalry or perceptual rivalry stimuli. Despite existing research into both types of rivalry, it remains unclear to what extent their underlying mechanisms involve common computational rules. Computational models of binocular rivalry mechanisms are generally tested against Levelt's four propositions, describing the psychophysical relation between stimulus strength and alternation dynamics in binocular rivalry. Here we use a bistable rotating structure-from-motion sphere, a generally studied form of perceptual rivalry, to demonstrate that Levelt's propositions also apply to the alternation dynamics of perceptual rivalry. Importantly, these findings suggest that bistability in structure-from-motion results from active cross-inhibition between neural populations with computational principles similar to those present in binocular rivalry. Thus, although the neural input to the computational mechanism of rivalry may stem from different cortical neurons and different cognitive levels the computational principles just prior to the production of visual awareness appear to be common to the two types of rivalry.

  8. Vision in Children and Adolescents with Autistic Spectrum Disorder: Evidence for Reduced Convergence

    Science.gov (United States)

    Milne, Elizabeth; Griffiths, Helen; Buckley, David; Scope, Alison

    2009-01-01

    Evidence of atypical perception in individuals with ASD is mainly based on self report, parental questionnaires or psychophysical/cognitive paradigms. There have been relatively few attempts to establish whether binocular vision is enhanced, intact or abnormal in those with ASD. To address this, we screened visual function in 51 individuals with…

  9. Effect of Common Visual Dysfunctions on Reading.

    Science.gov (United States)

    McPartland, Brian P.

    1985-01-01

    Six common visual dysfunctions are briefly explained and their relationships to reading noted: (1) ametropia, refractive error; (2) inaccurate saccades, the small jumping eye movements used in reading; (3) inefficient binocularity/fusion; (4) insufficient convergence/divergence; (5) heterophoria, imbalance in extra-ocular muscles; and (6)…

  10. Effects of eye and neck muscle proprioception on ocular motor control in normal and strabismic subjects

    OpenAIRE

    Han, Ying

    1998-01-01

    Abundant proprioceptive information originates in eye and neck muscles but their role in normal visual function is unknown. Under experimental conditions, proprioceptive activation induces illusory visual movement, whereas clinical evidence indicates that proprioceptive dysfunction causes disturbances in spatial orientation. Animal experiments have shown that proprioceptive disturbance impede normal development of binocular function. The present investigations examined the c...

  11. Is Quantum Mechanics needed to explain consciousness ?

    CERN Document Server

    Thomsen, Knud

    2007-01-01

    In this short comment to a recent contribution by E. Manousakis [1] it is argued that the reported agreement between the measured time evolution of conscious states during binocular rivalry and predictions derived from quantum mechanical formalisms does not require any direct effect of QM. The recursive consumption analysis process in the Ouroboros Model can yield the same behavior.

  12. Ambiguities in visual perception. The aperture problem and the role of eye movements in perceptual bistability

    NARCIS (Netherlands)

    Dam, L.C.J. van

    2006-01-01

    The research reported in this thesis is devoted to visual ambiguities. First, we investigated the assigned binocular disparity for an 'infinitely' long line, which was occluded at the flanks (aperture problem). We showed that from a geometrical point of view, matching of the partially occluded line

  13. Reading and visual search: a developmental study in normal children.

    Directory of Open Access Journals (Sweden)

    Magali Seassau

    Full Text Available Studies dealing with developmental aspects of binocular eye movement behaviour during reading are scarce. In this study we have explored binocular strategies during reading and during visual search tasks in a large population of normal young readers. Binocular eye movements were recorded using an infrared video-oculography system in sixty-nine children (aged 6 to 15 and in a group of 10 adults (aged 24 to 39. The main findings are (i in both tasks the number of progressive saccades (to the right and regressive saccades (to the left decreases with age; (ii the amplitude of progressive saccades increases with age in the reading task only; (iii in both tasks, the duration of fixations as well as the total duration of the task decreases with age; (iv in both tasks, the amplitude of disconjugacy recorded during and after the saccades decreases with age; (v children are significantly more accurate in reading than in visual search after 10 years of age. Data reported here confirms and expands previous studies on children's reading. The new finding is that younger children show poorer coordination than adults, both while reading and while performing a visual search task. Both reading skills and binocular saccades coordination improve with age and children reach a similar level to adults after the age of 10. This finding is most likely related to the fact that learning mechanisms responsible for saccade yoking develop during childhood until adolescence.

  14. Control and competition square off for primacy in the uranium market

    International Nuclear Information System (INIS)

    Who dominates? Who competes? How level is the playing field? And how free is the free market? Of more than academic interest, these questions are being thrashed out by a bevy of market participants. But resolution is no dainty game of croquet; it looks more like a rugby scrum. So grab your binoculars and let the games begin

  15. Stargazing Basics

    Science.gov (United States)

    Kinzer, Paul E.

    2015-07-01

    Preface; Introduction: why another stargazing guide?; Part I. Stargazing Techniques and Equipment: 1. With the naked eye alone; 2. Binoculars: the next step; 3. 'But I want a telescope!'; Part II. What's up There?: 4. The Solar System; 5. The deep sky; Part III. A Stargazing Glossary: Appendix 1. The Greek alphabet; Appendix 2. The constellations; Some simple star charts; Index.

  16. Use of preoperative assessment of positionally induced cyclotorsion: a video-oculographic study

    OpenAIRE

    Becker, R.; Krzizok, T H; Wassill, H

    2004-01-01

    Purpose: Positionally induced cyclotorsion could be an important factor concerning correction of astigmatism in refractive surgery. The method of binocular three dimensional infrared video-oculography (3D-VOG) was used to determine a possible influence of body position on cyclotorsion.

  17. 78 FR 20667 - Government-Owned Inventions; Availability for Licensing

    Science.gov (United States)

    2013-04-05

    ... potential derivative or mimicking compound would be unique and have the advantage of hitting a previously... binocular microscope (colposcope) that provide up to 25x optical magnification are used to create an... microscope, without interfering with the standard optical path and operation of the microscope, including...

  18. Presence of fusion in albinism after strabismus surgery augmented with botulinum toxin (type a) injection.

    Science.gov (United States)

    Tavakolizadeh, Sepideh; Farahi, Azadeh

    2013-08-01

    It is commonly accepted that albino patients with strabismus rarely achieve binocularity and depth perception after strabismus surgery. The presence of retino-geniculo-cortical misrouting, a hallmark of the visual system in albinism, does not necessarily cause total loss of binocular vision, however, not even in albino patients with strabismus. Recently some degrees of stereopsis were reported in albinism patients with minimal clinical nystagmus, if any, in the absence of strabismus. It is possible that patients with albinism and strabismus have binocular visual potential which appears after strabismus correction and provides appropriate postoperative alignment in the long term. Here we present two cases of clinically diagnosed oculocutaneous albinism, an 18-year-old girl and a 16-year-old boy, both with exotropia ≥40 prism diopter, who gained acceptable alignment and fusion after surgical correction of their strabismus as demonstrated on Bagolini testing. In cases of albinism accompanied by visual pathway abnormalities and strabismus, binocular visual potential is not impossible, and some levels can be expected. Thus, these patients, like other cases of strabismus, may benefit from treatment of strabismus at an earlier age to achieve appropriate alignment, cosmetic satisfaction, and a possibly increased chance of fusion. PMID:23908581

  19. Interocular conflict attracts attention.

    Science.gov (United States)

    Paffen, Chris L E; Hessels, Roy S; Van der Stigchel, Stefan

    2012-02-01

    During binocular rivalry, perception alternates.between dissimilar images presented dichoptically. Since.its discovery, researchers have debated whether the phenomenon is subject to attentional control. While it is now clear that attentional control over binocular rivalry is possible, the opposite is less evident: Is interocular conflict (i.e., the situation leading to binocular rivalry) able to attract attention?In order to answer this question, we used a change blindness paradigm in which observers looked for salient changes in two alternating frames depicting natural scenes. Each frame contained two images: one for the left and one for the right eye. Changes occurring in a single image (monocular) were detected faster than those occurring in both images (binocular). In addition,monocular change detection was also faster than detection in fused versions of the changed and unchanged regions. These results show that interocular conflict is capable of attracting attention, since it guides visual attention toward salient changes that otherwise would remain unnoticed for longer. The results of a second experiment indicated that interocular conflict attracts attention during the first phase of presentation, a phase during which the stimulus is abnormally fused [added]. PMID:22167536

  20. Quality of Visual Cue Affects Visual Reweighting in Quiet Standing

    Science.gov (United States)

    Moraes, Renato; de Freitas, Paulo Barbosa; Razuk, Milena; Barela, José Angelo

    2016-01-01

    Sensory reweighting is a characteristic of postural control functioning adopted to accommodate environmental changes. The use of mono or binocular cues induces visual reduction/increment of moving room influences on postural sway, suggesting a visual reweighting due to the quality of available sensory cues. Because in our previous study visual conditions were set before each trial, participants could adjust the weight of the different sensory systems in an anticipatory manner based upon the reduction in quality of the visual information. Nevertheless, in daily situations this adjustment is a dynamical process and occurs during ongoing movement. The purpose of this study was to examine the effect of visual transitions in the coupling between visual information and body sway in two different distances from the front wall of a moving room. Eleven young adults stood upright inside of a moving room in two distances (75 and 150 cm) wearing a liquid crystal lenses goggles, which allow individual lenses transition from opaque to transparent and vice-versa. Participants stood still during five minutes for each trial and the lenses status changed every one minute (no vision to binocular vision, no vision to monocular vision, binocular vision to monocular vision, and vice-versa). Results showed that farther distance and monocular vision reduced the effect of visual manipulation on postural sway. The effect of visual transition was condition dependent, with a stronger effect when transitions involved binocular vision than monocular vision. Based upon these results, we conclude that the increased distance from the front wall of the room reduced the effect of visual manipulation on postural sway and that sensory reweighting is stimulus quality dependent, with binocular vision producing a much stronger down/up-weighting than monocular vision. PMID:26939058

  1. Layer- and cell-type-specific subthreshold and suprathreshold effects of long-term monocular deprivation in rat visual cortex.

    Science.gov (United States)

    Medini, Paolo

    2011-11-23

    Connectivity and dendritic properties are determinants of plasticity that are layer and cell-type specific in the neocortex. However, the impact of experience-dependent plasticity at the level of synaptic inputs and spike outputs remains unclear along vertical cortical microcircuits. Here I compared subthreshold and suprathreshold sensitivity to prolonged monocular deprivation (MD) in rat binocular visual cortex in layer 4 and layer 2/3 pyramids (4Ps and 2/3Ps) and in thick-tufted and nontufted layer 5 pyramids (5TPs and 5NPs), which innervate different extracortical targets. In normal rats, 5TPs and 2/3Ps are the most binocular in terms of synaptic inputs, and 5NPs are the least. Spike responses of all 5TPs were highly binocular, whereas those of 2/3Ps were dominated by either the contralateral or ipsilateral eye. MD dramatically shifted the ocular preference of 2/3Ps and 4Ps, mostly by depressing deprived-eye inputs. Plasticity was profoundly different in layer 5. The subthreshold ocular preference shift was sevenfold smaller in 5TPs because of smaller depression of deprived inputs combined with a generalized loss of responsiveness, and was undetectable in 5NPs. Despite their modest ocular dominance change, spike responses of 5TPs consistently lost their typically high binocularity during MD. The comparison of MD effects on 2/3Ps and 5TPs, the main affected output cells of vertical microcircuits, indicated that subthreshold plasticity is not uniquely determined by the initial degree of input binocularity. The data raise the question of whether 5TPs are driven solely by 2/3Ps during MD. The different suprathreshold plasticity of the two cell populations could underlie distinct functional deficits in amblyopia. PMID:22114282

  2. Prospective evaluation of visual outcomes with three presbyopia-correcting intraocular lenses following cataract surgery

    Directory of Open Access Journals (Sweden)

    Ang RE

    2013-09-01

    Full Text Available RE Ang,1,2 GA Martinez,2,3 EM Cruz,1 AA Tiongson,1 AG Dela Cruz1 1Asian Eye Institute, Makati City, Philippines; 2Cardinal Santos Medical Center, San Juan City, Philippines; 3Pasig City General Hospital, Pasig City, Philippines Purpose: To compare the visual acuity and quality of vision achieved with three widely-used intraocular lenses (IOLs in subjects with bilateral cataracts. Patients and methods: This three-arm, parallel, prospective, partially masked, single-surgeon study randomized 78 subjects to receive bilateral Crystalens® Advanced Optics (AO accommodating IOLs, AcrySof® IQ ReSTOR® +3.0 multifocal IOLs, or TECNIS® Multifocal IOLs. Examinations were assessed through days 120 to 180. Results: The Crystalens AO group had statistically significantly better monocular and binocular, high-contrast (HC and low-contrast (LC uncorrected intermediate visual acuity, HC and LC distance-corrected intermediate visual acuity, and significantly fewer monocular and binocular halos and starbursts than did the ReSTOR and TECNIS groups. Monocular and binocular, HC and LC uncorrected near visual acuity exhibited no significant differences among the three lenses. For monocular and binocular HC distance-corrected near visual acuity, the Crystalens AO performed significantly better than the TECNIS and was not significantly different from the ReSTOR. For monocular and binocular LC distance-corrected near visual acuity, the Crystalens AO performed significantly better than both the ReSTOR and the TECNIS. Contrast sensitivity was clinically similar between groups. The Crystalens AO produced statistically fewer halos and starbursts. Conclusion: All three IOLs had excellent uncorrected acuity results at all distances and had good safety, confirming the established safety and effectiveness of these IOLs. Distance and near vision were similar between all three IOLs, and the Crystalens AO provided statistically significantly better intermediate vision. Keywords

  3. Neurological basis for eye movements of the blind.

    Directory of Open Access Journals (Sweden)

    Rosalyn M Schneider

    Full Text Available When normal subjects fix their eyes upon a stationary target, their gaze is not perfectly still, due to small movements that prevent visual fading. Visual loss is known to cause greater instability of gaze, but reported comparisons with normal subjects using reliable measurement techniques are few. We measured binocular gaze using the magnetic search coil technique during attempted fixation (monocular or binocular viewing of 4 individuals with childhood-onset of monocular visual loss, 2 individuals with late-onset monocular visual loss due to age-related macular degeneration, 2 individuals with bilateral visual loss, and 20 healthy control subjects. We also measured saccades to visual or somatosensory cues. We tested the hypothesis that gaze instability following visual impairment is caused by loss of inputs that normally optimize the performance of the neural network (integrator, which ensures both monocular and conjugate gaze stability. During binocular viewing, patients with early-onset monocular loss of vision showed greater instability of vertical gaze in the eye with visual loss and, to a lesser extent, in the normal eye, compared with control subjects. These vertical eye drifts were much more disjunctive than upward saccades. In individuals with late monocular visual loss, gaze stability was more similar to control subjects. Bilateral visual loss caused eye drifts that were larger than following monocular visual loss or in control subjects. Accurate saccades could be made to somatosensory cues by an individual with acquired blindness, but voluntary saccades were absent in an individual with congenital blindness. We conclude that the neural gaze-stabilizing network, which contains neurons with both binocular and monocular discharge preferences, is under adaptive visual control. Whereas monocular visual loss causes disjunctive gaze instability, binocular blindness causes both disjunctive and conjugate gaze instability (drifts and nystagmus

  4. Hawk eyes I: diurnal raptors differ in visual fields and degree of eye movement.

    Directory of Open Access Journals (Sweden)

    Colleen T O'Rourke

    Full Text Available BACKGROUND: Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. METHODOLOGY/PRINCIPAL FINDINGS: We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33° and wide blind areas (∼82°, but intermediate degree of eye movement (∼5°, which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°, small blind areas (∼60°, and high degree of eye movement (∼8°, which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1° may help stabilize the image when hovering above prey before an attack. CONCLUSIONS: We conclude that: (a there are between-species differences in visual field configuration in these diurnal raptors; (b these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats; (c variations in the degree of eye movement between species appear associated with foraging strategies; and (d the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence

  5. [Early detection and treatment of strabismus].

    Science.gov (United States)

    Mojon, Daniel

    2016-01-01

    An early diagnosis of strabismus is important in order to rule out treatable organic causes and in children, if indicated, to start as early as possible with an amblyopia treatment. Early detection will also decrease the risk for accidents secondary to diplopia, to the loss of binocular vision and to the restriction of the binocular visual field in case of esodeviations. The following therapeutic options exist: in some cases the prescription of the correct refraction will be sufficient, for small deviations a prismatic correction may allow a longstanding treatment, for larger or incomitant deviations strabismus surgery will be necessary, which nowadays can be performed using minimal-invasive technique on an outpatient base. PMID:26982644

  6. How Much of the Unconscious Is Just Pre - Threshold?

    Directory of Open Access Journals (Sweden)

    Manfred Wilhem Fahle

    2011-10-01

    Full Text Available Visual awareness is a specific form of consciousness. Binocular rivalry, the alternation of visual consciousness resulting when the two eyes view differing stimuli, allows one to experimentally investigate visual awareness. Observers usually indicate the gradual changes of conscious perception in binocular rivalry by a binary measure: pressing a button. However, in our experiments, gradual measures such as pupil and joystick movements start around 590 ms before observers press a button, apparently accessing even pre-conscious processes. Our gradual measures permit monitoring the built-up, over time, of decision processes and that should not be considered as abrupt events. Changes in analogue measures occurring before button presses signalling decisions do not prove these decisions are taken subconsciously – eliminating free will - but just prepared pre-thresholdly.

  7. [Dichoptic training for amblyopia].

    Science.gov (United States)

    Bach, M

    2016-04-01

    Dichoptic training is a promising new therapeutic approach to amblyopia, which employs simultaneous and separate stimulation of both eyes (thus dichoptic). The contrast for the good eye is reduced thus aiming at a balance with the amblyopic eye. In contrast to monocular patching, binocular vision is trained by video game tasks that can only be solved binocularly. To date the average gain in visual acuity achieved in currently available studies is only 0.20 ± 0.07 logMAR and is not significantly better than competing treatment options. This article explains the basic approach of dichoptic training, summarizes pertinent studies, names unsolved problems and closes with a personal critical assessment. PMID:27059985

  8. Ocular disconjugacy cannot be measured without establishing a solid spatial reference [v2; ref status: indexed, http://f1000r.es/5as

    Directory of Open Access Journals (Sweden)

    Jun Maruta

    2015-04-01

    Full Text Available This correspondence points out a need for clarification concerning the methodology utilized in the study “Eye tracking detects disconjugate eye movements associated with structural traumatic brain injury and concussion”, recently published in Journal of Neurotrauma. The authors of the paper state that binocular eye movements were recorded using a single-camera video-oculography technique and that binocular disconjugate characteristics were analyzed without calibration of eye orientation. It is claimed that a variance-based disconjugacy metric was found to be sensitive to the severity of a concussive brain injury and to the status of recovery after the original injury. However, the reproducibility of the paper’s findings may be challenged simply by the paucity of details in the methodological description. More importantly, from the information supplied or cited in the paper, it is difficult to evaluate the validity of the potentially interesting conclusions of the paper.

  9. Vector model for mapping of visual space to subjective 4-D sphere

    International Nuclear Information System (INIS)

    Here we present a mathematical model of binocular vision that maps a visible physical world to a subjective perception of it. The subjective space is a set of 4-D vectors whose components are outputs of four monocular neurons from each of the two eyes. Monocular neurons have one of the four types of concentric receptive fields with Gabor-like weighting coefficients. Next this vector representation of binocular vision is implemented as a pool of neurons where each of them is selective to the object's particular location in a 3-D visual space. Formally each point of the visual space is being projected onto a 4-D sphere. Proposed model allows determination of subjective distances in depth and direction, provides computational means for determination of Panum's area and explains diplopia and allelotropia

  10. Comparative Study of Refractive Errors, Strabismus, Microsaccades, and Visual Perception Between Preterm and Full-Term Children With Infantile Cerebral Palsy.

    Science.gov (United States)

    Kozeis, Nikolaos; Panos, Georgios D; Zafeiriou, Dimitrios I; de Gottrau, Philippe; Gatzioufas, Zisis

    2015-07-01

    The purpose of this study was to examine the refractive status, orthoptic status and visual perception in a group of preterm and another of full-term children with cerebral palsy, in order to investigate whether prematurity has an effect on the development of refractive errors and binocular disorders. A hundred school-aged children, 70 preterm and 30 full-term, with congenital cerebral palsy were examined. Differences for hypermetropia, myopia, and emmetropia were not statistically significant between the 2 groups. Astigmatism was significantly increased in the preterm group. The orthoptic status was similar for both groups. Visual perception was markedly reduced in both groups, but the differences were not significant. In conclusion, children with cerebral palsy have impaired visual skills, leading to reading difficulties. The presence of prematurity does not appear to represent an additional risk factor for the development of refractive errors and binocular disorders. PMID:25296927

  11. Understanding, detecting and managing strabismus

    Directory of Open Access Journals (Sweden)

    Eugene M Helveston

    2010-03-01

    Full Text Available Whereas many animals have eyes located on either side of their head (such as horses, for example, the eyes of humans look forwards - in the same direction. When normal, the eyes move in a coordinated manner, so that the object being looked at is centred in each eye. Because the eyes are set a small distance apart, the image in each eye is slightly different. The brain fuses the images coming from both eyes to produce a three-dimensional image that has depth. This three-dimensional vision, also known as stereoscopic or binocular vision, gives us depth perception. This allows us to judge distances more accurately, especially with objects close to us. Try to thread a needle with only one eye open and you will see the advantage of binocular vision!

  12. Pupillary response to direct and consensual chromatic light stimuli

    DEFF Research Database (Denmark)

    Traustason, Sindri; Brondsted, Adam Elias; Sander, Birgit; Lund-Andersen, Henrik

    2016-01-01

    PURPOSE: To assess whether the direct and consensual postillumination (ipRGC-driven) pupil light responses to chromatic light stimuli are equal in healthy subjects. METHODS: Pupil responses in healthy volunteers were recorded using a prototype binocular chromatic pupillometer (IdeaMedical, Copenh......PURPOSE: To assess whether the direct and consensual postillumination (ipRGC-driven) pupil light responses to chromatic light stimuli are equal in healthy subjects. METHODS: Pupil responses in healthy volunteers were recorded using a prototype binocular chromatic pupillometer (Idea...... software. Subjects were randomized to receive light stimuli at either the right or left eye after 5 min of dark adaptation. Pupil light responses were recorded in both eyes for 10 seconds before illumination, during illumination and 50 seconds after illumination with red and blue light. Three variables...

  13. The effect of a monocular helmet-mounted display on aircrew health: a 10-year prospective cohort study of Apache AH MK 1 pilots: study midpoint update

    Science.gov (United States)

    Hiatt, Keith L.; Rash, Clarence E.; Watters, Raymond W.; Adams, Mark S.

    2009-05-01

    A collaborative occupational health study has been undertaken by Headquarters Army Aviation, Middle Wallop, UK, and the U.S. Army Aeromedical Research Laboratory, Fort Rucker, Alabama, to determine if the use of the Integrated Helmet and Display Sighting System (IHADSS) monocular helmet-mounted display (HMD) in the Apache AH Mk 1 attack helicopter has any long-term (10-year) effect on visual performance. The test methodology consists primarily of a detailed questionnaire and an annual battery of vision tests selected to capture changes in visual performance of Apache aviators over their flight career (with an emphasis on binocular visual function). Pilots using binocular night vision goggles serve as controls and undergo the same methodology. Currently, at the midpoint of the study, with the exception of a possible colour discrimination effect, there are no data indicating that the long-term use of the IHADSS monocular HMD results in negative effects on vision.

  14. Inspection of the TRIGA mark-2 reactor tank Vienna in July 1988

    International Nuclear Information System (INIS)

    During a routine visual inspection with binoculars in spring 1988, three corrosion craters were observed on the top of the former 'thermalizing column', now being used as neutron radiography facility. The location of the corrosion craters is indicated in fig.1. As the optical resolution of the binoculars was not sufficient it was decided to ask for the support of the KFKI Budapest with its nuclear underwater telescope. The telescope and other equipment used is described and the results of the inspection are presented. It is concluded that the three major corrosion craters do not pose any safety hazard because the corrosion depth is small compared to the material thickness. However, further close monitoring of the corrosion craters is recommended. 24 figs. (qui)

  15. Environmental Recognition and Guidance Control for Autonomous Vehicles using Dual Vision Sensor and Applications

    Science.gov (United States)

    Moriwaki, Katsumi; Koike, Issei; Sano, Tsuyoshi; Fukunaga, Tetsuya; Tanaka, Katsuyuki

    We propose a new method of environmental recognition around an autonomous vehicle using dual vision sensor and navigation control based on binocular images. We consider to develop a guide robot that can play the role of a guide dog as the aid to people such as the visually impaired or the aged, as an application of above-mentioned techniques. This paper presents a recognition algorithm, which finds out the line of a series of Braille blocks and the boundary line between a sidewalk and a roadway where a difference in level exists by binocular images obtained from a pair of parallelarrayed CCD cameras. This paper also presents a tracking algorithm, with which the guide robot traces along a series of Braille blocks and avoids obstacles and unsafe areas which exist in the way of a person with the guide robot.

  16. On the 'Geminion'

    International Nuclear Information System (INIS)

    The ''binocular'' events newly observed by the Chacaltaya emulsion chamber experiment are discussed on the basis of the theory of hadronic matter proposed previously. Hadronic matter (hadrons, fireballs etc.) consists of a large number of pairs of basic particles (''bare'' quarks) and its mass density is approximately uniform and nearly common to all hadronic matter. It is possible and even probable, in our picture, that the ''binocular'' event, at least some of them, is a fission of the SH-quantum (a fireball of the mass 20 - 30 GeV) into a ''physical'' quark and a ''physical'' anti-quark (the mass of the ''physical quark is assumed to be 10 GeV). The possibility of finding ''physical'' quarks through the intermediate state of the SH-quantum in a future high energy colliding beams (e.g. 200 GeV x 200 GV) is mentioned. (author)

  17. VizieR Online Data Catalog: Photometry of the Type Ib/c SN2013ge (Drout+, 2016)

    Science.gov (United States)

    Drout, M. R.; Milisavljevic, D.; Parrent, J.; Margutti, R.; Kamble, A.; Soderberg, A. M.; Challis, P.; Chornock, R.; Fong, W.; Frank, S.; Gehrels, N.; Graham, M. L.; Hsiao, E.; Itagaki, K.; Kasliwal, M.; Kirshner, R. P.; Macomb, D.; Marion, G. H.; Norris, J.; Phillips, M. M.

    2016-06-01

    We obtained UV and optical photometry of the Type Ib/c SN2013ge spanning 466 days. Data were obtained with the UV Optical Telescope (UVOT) on board Swift (w2, m2 , w1, u, b, and v bands; table1.dat), the 0.4 m telescope at the Challis Astronomical Observatory (CAO; B, V, R, and I bands; table2.dat), the 1.2m telescope plus KeplerCam CCD at the Fred Lawrence Whipple Observatory (FLWO; B, V, r, and i bands; table3.dat), the MMTCam instrument mounted on the 6.5 m MMT telescope, the Large Binocular Camera (LBC) mounted on the Large Binocular Telescope (LBT), and the Inamori-Magellan Areal Camera and Spectrograph (IMACS) on Magellan-Baade (r, i, and z bands; table4.dat). (4 data files).

  18. Management of strabismus in thyroid eye disease.

    Science.gov (United States)

    Harrad, R

    2015-02-01

    Thyroid eye disease is an auto-immune condition characterised by an acute inflammatory phase followed by a fibrotic phase, which sometimes leads to restricted eye movements and diplopia. Medical treatment with systemic steroids with or without orbital radiotherapy and immunosuppression can control the inflammatory response. Strabismus surgery should be carried out only after the inflammation is no longer active and after any decompression surgery. Surgery comprises recession of tight muscles using adjustable sutures so as to maximise the area of binocular single vision. There is debate as to whether adjustable sutures should be used for the inferior rectus muscle. Patients should be encouraged to have realistic expectations, as binocular single vision may not be achievable in all directions of gaze and lid retraction may be made worse by surgery. PMID:25523204

  19. Eficacia de la estimulación neurosensorial en ambliopías

    OpenAIRE

    Argilés Sans, Marc

    2011-01-01

    La ambliopía o comúnmente conocida como "ojo vago" es un trastorno de origen cortical i binocular que afecta a la función visual y tiene una incidencia de un 1-4% de la población. Los métodos clásicos de tratamiento se basan en la oclusión del ojo menos afectado, penalización con fármacos o terapia visual. El vigente trabajo ha sido llevado a cabo con el objetivo de determinar si la terapia con estimulación sensorial mediante el Trans-lid Binocular Interactor (TBI) mejora la agudeza visual, s...

  20. Undetectable Changes in Image Resolution of Luminance-Contrast Gradients Affect Depth Perception

    OpenAIRE

    Tsushima, Yoshiaki; Komine, Kazuteru; Sawahata, Yasuhito; Morita, Toshiya

    2016-01-01

    A great number of studies have suggested a variety of ways to get depth information from two dimensional images such as binocular disparity, shape-from-shading, size gradient/foreshortening, aerial perspective, and so on. Are there any other new factors affecting depth perception? A recent psychophysical study has investigated the correlation between image resolution and depth sensation of Cylinder images (A rectangle contains gradual luminance-contrast changes.). It was reported that higher ...

  1. Undetectable changes in image resolution of luminance-contrast gradients affect depth perception.

    OpenAIRE

    Yoshiaki eTsushima; Kazuteru eKomine; Yasuhito eSawahata; Toshiya eMorita

    2016-01-01

    A great number of studies have suggested a variety of ways to get depth information from two dimensional images such as binocular disparity, shape-from-shading, size gradient/ foreshortening, aerial perspective, and so on. Are there any other new factors affecting depth perception? A recent psychophysical study has investigated the correlation between image resolution and depth sensation of Cylinder images (A rectangle contains gradual luminance-contrast changes.). It was reported that higher...

  2. Characterisation of Quaternary sediments from East Anglia

    OpenAIRE

    Mitchell, C J; Bloodworth, A.J.; Evans, E. J.

    1996-01-01

    This report describes the mineralogical investigations of Quaternary sediments,mainly Cromer Till, collected from East Anglia. The main aim of the work was to characterise the mineralogical and physical properties of the till samples to facilitate correlation between tills from different localities. The clast composition of the samples was determined using a binocular microscope and the mineralogy of the matrix was determined using X-ray diffraction and thermogravimetry. Calibration charts we...

  3. Stereoscopic Vision in the Absence of the Lateral Occipital Cortex

    OpenAIRE

    Read, JC; Phillipson, GP; Serrano-Pedraza, I; Milner, AD; Parker, AJ

    2010-01-01

    Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better th...

  4. Continuous flash suppression reduces negative afterimages

    OpenAIRE

    Tsuchiya, Naotsugu; Koch, Christof

    2005-01-01

    Illusions that produce perceptual suppression despite constant retinal input are used to manipulate visual consciousness. Here we report on a powerful variant of existing techniques, continuous flash suppression. Distinct images flashed successively at approx10 Hz into one eye reliably suppress an image presented to the other eye. The duration of perceptual suppression is at least ten times greater than that produced by binocular rivalry. Using this tool we show that the strength of the negat...

  5. EXERCÍCIOS ENVOLVENDO A MAGNITUDE LIMITE NO ENSINO DE ASTRONOMIA

    OpenAIRE

    Lev Vertchenko; Tomás de Aquino Silveira

    2010-01-01

    We present a set of exercises and activities, designed for Basic Astronomy disciplines and inspired by Ausubel¿s multi-contextual approach, relating the limit magnitude concept to the light catching power of an optical instrument. These exercises are compared with stars count, through naked-eye observations, or those made with the aid of optical instruments, and through the use of star charts software. Meanwhile, the student has the opportunity to become familiarized with the sky, binoculars ...

  6. Prism vergence measurements following adaptation to a base out prism

    OpenAIRE

    Tuff, L.C.; Firth, A Y; Griffiths, H.J.

    2000-01-01

    This study examines the effect of adaptation on the prism vergence range following an induced deviation. Five young adult subjects, with normal binocular functions, underwent fusional verfence testing to base in prisms before and after wearing a 10(Δ) base out Fresnel prism. The Fresnel prism was worn for a period of 2, 5, or 10 min on each of three separate occasions. The base in fusional vergence showed no statistical difference before or after adaptation, for any of the time periods. Also ...

  7. [Use of botulinum toxin in strabismus].

    Science.gov (United States)

    Wabbels, B

    2016-07-01

    Botulinum toxin can be a useful tool for treating acute sixth nerve palsy and excessive eye deviations due to unstable Graves' disease, when surgery is not yet possible. The diagnostic injection for estimation of possible postoperative double vision also makes sense. In convergence spasms, periocular botulinum toxin injections can be a therapeutic option. Botulinum toxin is not a first line option in infantile esotropia without binocularity or in adult horizontal strabismus. Side effects include ptosis and vertical deviations. PMID:27369733

  8. Current practices of diagnostic techniques requir- ing the use of ophthalmic drugs among KwaZulu- Natal optometrists*

    OpenAIRE

    K. P. Mashige; K. S. Naidoo

    2009-01-01

    In anendeavour to improve the quality of optometric eye care services in South Africa, the scope of practice was expanded to include the use of ocular diagnostic procedures such as goniosco-py that require the use of ophthalmic drugs. The purpose of this study was to assess the practices of specific diagnostic techniques (contact tonometry, 78 D/90 D lens fundus examination, binocular indirect ophthalmoscopy and gonioscopy) requiring the use of ophthalmic drugs among optometrists in KwaZulu-N...

  9. Surgical magnification for intracapsular cataract surgery in a rural hospital

    OpenAIRE

    Braganza Andrew; Cheng Arthur; Thomas Ravi; Muliyil Jayaprakash

    1996-01-01

    Intracapsular cataract extraction is still the most common type of operation performed in India, especially in eye camps, and most of these are done without magnification. To assess the surgical outcome of intracapsular cataract surgery in a rural hospital with various magnifying systems, 121 consecutive eyes (121 patients) with uncomplicated cataract were randomly allocated to surgery with the operating microscope, binocular loupe or unaided eye. The surgery was performed by either consultan...

  10. Signal-light nomogram

    Science.gov (United States)

    Gordon, J. I.; Edgerton, C. F.; Duntley, S. Q.

    1975-01-01

    A nomogram is presented for predicting the sighting range for white, steady-burning signal lights. The theoretical and experimental bases are explained and instructions are provided for its use for a variety of practical problems concerning the visibility of signal lights. The nomogram is appropriate for slant path as well as horizontal sightings, and the gain of range achieved by utilizing binoculars can be predicted by use of it.

  11. ЛОКАЛЬНЫЕ ГЕОХИМИЧЕСКИЕ НАБЛЮДЕНИЯ ПЫЛЕАЭРОЗОЛЕЙ В ПРЕДЕЛАХ ГОРОДСКОЙ И ПРИГОРОДНОЙ ЗОН

    OpenAIRE

    Таловская, А.; Язиков, Е.

    2006-01-01

    Results of the detailed monitoring (2001-2006) of the dust-aerosols fallouts on the snow cover in the southern district of Tomsk and in Timiryazevo (suburb located in 4-5 kms from the town) are presented. Investigations are based on a study of the mineral composition of a solid residue of snow using a binocular stereoscopic microscope, radiography analysis and impulse cathodic luminescence method. Geochemical composition was studied with the help of neutron-activation analysis technique and f...

  12. Behavior and foraging technique of the Ingram's squirrel Guerlinguetus ingrami (Sciuridae: Rodentia) in an Araucaria moist forest fragment

    OpenAIRE

    Calebe Pereira Mendes; José Flávio Cândido-Jr

    2014-01-01

    This work describes the foraging techniques, body positions and behavior of free-ranging Ingram's squirrel Guerlinguetus ingrami Thomas, 1901 in a region of the Araucaria moist forest, in the Atlantic Forest of southern Brazil. The animals were observed using the "all occurrence sampling" method with the aid of binoculars and a digital camcorder. All behaviors were described in diagrams and an ethogram. We recorded five basic body positions, 24 behaviors, two food choices, and three feeding s...

  13. Genetics and development of the optic chiasm

    OpenAIRE

    Herrera, Eloisa; García-Frigola, Cristina

    2008-01-01

    In animals with binocular vision, retinal fibers either project across the midline or they remain on the same side of the ventral diencephalon, forming an X-shaped commissure known as the optic chiasm. The correct formation of the optic chiasm during development is essential to establish a fully functional visual system. Visual dysfunction associated with axonal misrouting at the optic chiasm has been described in albino individuals and in patients with non-decussating retinal-fugal fiber syn...

  14. Advantages and disadvantages of multifocal contact lens correction of presbyopia in patients with myopic refraction

    OpenAIRE

    A.G. Shchuko; N. N. Seliverstova; E. A. Rogozhnikova; O. I. Rozanova

    2014-01-01

    Purpose: To evaluate the results of multifocal contact correction of presbyopia in subjects with myopic refraction.Methods: The study included 28 patients with myopia (range 43 to 54 years) in conditions of routine contact correction of vision. The examination was repeated a month later after wearing of multifocal contact lenses. The following parameters were assessed: far visual acuity, near and intermediate visual acuity (monocular and binocular), spatial contrast sensitivity, stereo vision...

  15. A pilot study of disparity vergence and near dissociated phoria in convergence insufficiency patients before vs. after vergence therapy

    OpenAIRE

    Alvarez, Tara L.

    2015-01-01

    Purpose: This study examined the relationship between the near dissociated phoria and disparity vergence eye movements. Convergence insufficiency (CI) patients before vergence therapy were compared to: (1) the same patients after vergence therapy; and (2) binocularly normal controls (BNC). Methods: Sixteen subjects were studied—twelve BNC and four with CI. Measurements from the CI subjects were obtained before and after 18 h of vergence eye movement therapy. The near dissociated phoria was...

  16. Functional activity within the frontal eye fields, posterior parietal cortex, and cerebellar vermis significantly correlates to symmetrical vergence peak velocity: an ROI-based, fMRI study of vergence training

    OpenAIRE

    Alvarez, Tara L.

    2014-01-01

    Convergence insufficiency (CI) is a prevalent binocular vision disorder with symptoms that include double/blurred vision, eyestrain, and headaches when engaged in reading or other near work. Randomized clinical trials support that Office-Based Vergence and Accommodative Therapy with home reinforcement leads to a sustained reduction in patient symptoms. However, the underlying neurophysiological basis for treatment is unknown. Functional activity and vergence eye movements were quantified from...

  17. Preferred clinical practice in convergence insufficiency in India: A survey

    OpenAIRE

    Patwardhan Sourabh; Sharma Pradeep; Saxena Rohit; Khanduja Sumeet

    2008-01-01

    Purpose: Convergence insufficiency (CI) is a common binocular vision disorder. However, there is a lack of consensus regarding the treatment most appropriate for CI. The aim of the study was to investigate the treatment for CI by surveying the ophthalmologists regarding the most common treatment modalities used in India. Materials and Methods: Four hundred questionnaires were distributed amongst ophthalmologists attending different sessions of the Delhi Ophthalmological Society annual conf...

  18. PIXE Analysis for the pigment identification in the Nizet manucript (18th century)

    OpenAIRE

    Machowski, Mélanie; Calvo del Castillo, Helena; Oger, Cécile; Chene, Grégoire; Strivay, David

    2013-01-01

    Written in 1740, the Nizet Manuscript is a heraldry book compiling the genealogy of the Nizet family (Verviers, Belgium). It presents a large number of hand-painted heraldries in traditional heraldic colours; the gold- and silver-like colours have undergone alteration and induced the degradation of the paper. The first inspection of the book with a binocular lens and UV-visible spectroscopy has led to the selection of representative points to be studied by PIXE analysis for the different g...

  19. Psychophysically measured task strategy for disparity detection is reflected in V2 neurons

    OpenAIRE

    Nienborg, Hendrikje; Cumming, Bruce G.

    2007-01-01

    In perceptual tasks, subjects attempt to rely on their most informative cues. Such strategic choices should be reflected in the types of sensory neurons used. We investigated this in a binocular disparity discrimination task. Using psychophysical reverse-correlation, also known as image classification, we identified the perceptual strategy in two macaques. Correlation between reported disparity sign and disparity noise samples on each trial yielded detection ‘filters’. Filter amplitude at nea...

  20. Conscious experience of a face without face-specific neural activity

    OpenAIRE

    Leon Deouell; Shlomo Bentin

    2008-01-01

    Understanding how conscious coherent percepts are formed from the sensory input is one of the most important goals of neuroscience. However, as frequently illustrated by visual illusions, conscious perception is not a direct reflection of the sensory input, and major parts of the input may evade conscious awareness. A dramatic demonstration of dissociation between sensory input and conscious perception occurs in binocular rivalry (BR): when each eye is presented with a different input, the tw...

  1. Bondi-type accretion in the Reissner-Nordstr\\"om-(anti-)de Sitter spacetime

    CERN Document Server

    Ficek, Filip

    2015-01-01

    In this paper I study stationary, spherically symmetric accretion of fluids onto a charged black hole in the presence of the cosmological constant. For some isothermal equations of state it is possible to obtain analytic solutions. In the case of a radiation fluid I point out a connection between locations of the horizons and the sonic (critical) points. In specific cases the solutions form closed, binoculars-like trajectories in a phase diagram of the velocity vs. radius.

  2. Myasthenia gravis

    OpenAIRE

    Juel, Vern C; Massey, Janice M

    2007-01-01

    Myasthenia gravis (MG) is a rare, autoimmune neuromuscular junction disorder. Contemporary prevalence rates approach 1/5,000. MG presents with painless, fluctuating, fatigable weakness involving specific muscle groups. Ocular weakness with asymmetric ptosis and binocular diplopia is the most typical initial presentation, while early or isolated oropharyngeal or limb weakness is less common. The course is variable, and most patients with initial ocular weakness develop bulbar or limb weakness ...

  3. Myasthenia gravis

    OpenAIRE

    Massey Janice M; Juel Vern C

    2007-01-01

    Abstract Myasthenia gravis (MG) is a rare, autoimmune neuromuscular junction disorder. Contemporary prevalence rates approach 1/5,000. MG presents with painless, fluctuating, fatigable weakness involving specific muscle groups. Ocular weakness with asymmetric ptosis and binocular diplopia is the most typical initial presentation, while early or isolated oropharyngeal or limb weakness is less common. The course is variable, and most patients with initial ocular weakness develop bulbar or limb ...

  4. Breaking Continuous Flash Suppression: A New Measure of Unconscious Processing during Interocular Suppression?

    OpenAIRE

    Stein, Timo; Hebart, Martin N; Sterzer, Philipp

    2011-01-01

    Until recently, it has been thought that under interocular suppression high-level visual processing is strongly inhibited if not abolished. With the development of continuous flash suppression (CFS), a variant of binocular rivalry, this notion has now been challenged by a number of reports showing that even high-level aspects of visual stimuli, such as familiarity, affect the time stimuli need to overcome CFS and emerge into awareness. In this “breaking continuous flash suppression” (b-CFS) p...

  5. Breaking continuous flash suppression: A new measure of unconscious processing during interocular suppression?

    OpenAIRE

    Timo eStein; Hebart, Martin N; Philipp eSterzer

    2011-01-01

    Until recently, it has been thought that under interocular suppression high-level visual processing is strongly inhibited if not abolished. With the development of continuous flash suppression (CFS), a variant of binocular rivalry, this notion has now been challenged by a number of reports showing that even high-level aspects of visual stimuli, such as familiarity, affect the time stimuli need to overcome CFS and emerge into awareness. In this breaking CFS (b-CFS) paradigm, differential uncon...

  6. Fear modulates visual awareness similarly for facial and bodily expressions

    OpenAIRE

    Stienen, Bernard M. C.; Beatrice ede Gelder

    2011-01-01

    BackgroundSocial interaction depends on a multitude of signals carrying information about the emotional state of others. Past research has focused on the perception of facial expressions while perception of whole body signals has only been studied recently. The relative importance of facial and bodily signals is still poorly understood. In order to better understand the relative contribution of affective signals from the face only or from the rest of the body we used a binocular rivalry exper...

  7. Product presentation on DVD

    OpenAIRE

    Willsund, John

    2008-01-01

    The purpose of this thesis is to seek answers to the questions how the sales in a photo shop can be affected by animated commercial presentations and what the costs of producing such presentations would be. The costs are calculated from three different scenarios. The presentations produced has been for one single camera model and for selected products within three product groups; binoculars, digital cameras and printed matters. The task has included image processing of self-shot and existing ...

  8. Extrusion of hydrogel exoplant into upper eyelid 16 years after a scleral buckle procedure

    Directory of Open Access Journals (Sweden)

    Chirag P Shah

    2011-01-01

    Full Text Available Sixteen years after scleral buckle surgery with a hydrogel episcleral exoplant, a 43-year-old woman presented with progressive binocular diplopia, ptosis, and an expanding mass in her upper eyelid. She underwent surgical removal of the hydrogel exoplant through an anterior approach. The exoplant proved to be friable, fragmented, and encapsulated in a fibrous tissue; the exoplant was removed in its entirety. Postoperatively, the eyelid mass resolved, while her diplopia and ptosis improved slightly.

  9. Quantifying how the combination of blur and disparity affects the perceived depth

    OpenAIRE

    Wang, Junle; Barkowsky, Marcus; Ricordel, Vincent; Le Callet, Patrick

    2011-01-01

    The influence of a monocular depth cue, blur, on the apparent depth of stereoscopic scenes will be studied in this paper. When 3D images are shown on a planar stereoscopic display, binocular disparity becomes a pre-eminent depth cue. But it induces simultaneously the conflict between accommodation and vergence, which is often considered as a main reason for visual discomfort. If we limit this visual discomfort by decreasing the disparity, the apparent depth also decreases. We propose to decre...

  10. Clarifying how defocus blur and disparity affect the perceived depth

    OpenAIRE

    Wang, Junle; Barkowsky, Marcus; Ricordel, Vincent; Le Callet, Patrick

    2011-01-01

    Human visual system takes advantage of different cues simultaneously to provide us the perception of depth. When 3D images are shown on a planar stereoscopic display, binocular disparity becomes a pre-eminent depth cue. But it induces simultaneously the conflict between accommodation and vergence, which is often considered as a main reason for visual discomfort. If we limit this visual discomfort by decreasing the disparity, the apparent depth also decreases. We propose to decrease the (binoc...

  11. Multiple Episodes of Convergence in Genes of the Dim Light Vision Pathway in Bats

    OpenAIRE

    Shen, Yong-Yi; Lim, Burton K; Liu, He-Qun; Liu, Jie; David M. Irwin; Zhang, Ya-Ping

    2012-01-01

    The molecular basis of the evolution of phenotypic characters is very complex and is poorly understood with few examples documenting the roles of multiple genes. Considering that a single gene cannot fully explain the convergence of phenotypic characters, we choose to study the convergent evolution of rod vision in two divergent bats from a network perspective. The Old World fruit bats (Pteropodidae) are non-echolocating and have binocular vision, whereas the sheath-tailed bats (Emballonurida...

  12. Flight performance using a hyperstereo helmet-mounted display: adaptation to hyperstereopsis

    Science.gov (United States)

    Stuart, Geoffrey W.; Jennings, Sion A.; Kalich, Melvyn E.; Rash, Clarence E.; Harding, Thomas H.; Craig, Gregory L.

    2009-05-01

    Modern helmet-mounted night vision devices, such as the Thales TopOwlTM helmet, project imagery from intensifiers mounted on the sides of the helmet onto the helmet visor. This increased effective inter-ocular separation distorts several cues to depth and distance that are grouped under the term "hyperstereopsis". Stereoscopic depth perception, at near to moderate distances (several hundred metres), is subject to magnification of binocular disparities. Absolute distance perception at near distances (a few metres) is affected by increased "differential perspective" as well as an increased requirement for convergence of the eyes to achieve binocular fixation. These distortions result in visual illusions such as the "bowl effect" where the ground appears to rise up near the observer. Previous reports have indicated that pilots can adapt to these distortions after several hours of exposure. The present study was concerned with both the time course and the mechanisms involved in this adaptation. Three test pilots flew five sorties with a hyperstereo night vision device. Initially, pilots reported that they were compensating for the effects of hyperstereopsis, but on the third and subsequent sorties all reported perceptual adaptation, that is, a reduction in illusory perception. Given that this adaptation was the result of intermittent exposure, and did not produce visual aftereffects, it was not due to the recalibration of the relationship between binocular cues and depth/distance. A more likely explanation of the observed visual adaptation is that it results from a discounting of distorted binocular cues in favour of veridical monocular cues, such as familiar size, motion parallax and linear perspective.

  13. Acquired pendular nystagmus: its characteristics, localising value and pathophysiology

    OpenAIRE

    Gresty, MA; Ell, LL; Findley, Lj

    1982-01-01

    Investigations were made of 16 patients with acquired pendular nystagmus and a further 32 cases reported in the literature were reviewed. Amongst our own patients two thirds had multiple sclerosis, almost one third a cerebrovascular accident or angioma and two had optic atrophy with squint. The nystagmus took forms which could be monocular or binocular, conjugate or disconjugate and could involve movements about single or multiple axes. Spectral analysis was used to characterise the amplitude...

  14. TELEMEDICINE WITH SMART SOFTWARE FOR RETINOPATHY OF PREMATURITY SCREENING: EXPERIENCE FROM A PROGRAM IN THE USA AND PROSPECTS FOR USE

    OpenAIRE

    Trese, M; Denisova, E; Katargina, L.

    2014-01-01

    Retinopathy of prematurity (ROP) remains a leading cause of preventable blindness in premature infants worldwide. ROP screening is the most important part of ROP care, which determines proper timing for treatment. The standard method for diagnosis of ROP bedside binocular indirect ophthalmoscopy (BIO) has many limitations. Effectiveness of a telemedicine approach, using wide angle remote digital fundus imaging and Smart Software for ROP screening, was demonstrated. Telemedicine can supplant B...

  15. Pain and stress assessment after retinopathy of prematurity screening examination: Indirect ophthalmoscopy versus digital retinal imaging

    OpenAIRE

    Moral-Pumarega M; Caserío-Carbonero Sonia; De-La-Cruz-Bértolo Javier; Tejada-Palacios Pilar; Lora-Pablos David; Pallás-Alonso Carmen R

    2012-01-01

    Abstract Background Increasingly, neonatal clinics seek to minimize painful experiences and stress for premature infants. Fundoscopy performed with a binocular indirect ophthalmoscope is the reference examination technique for screening of retinopathy of prematurity (ROP), and it is associated with pain and stress. Wide-field digital retinal imaging is a recent technique that should be evaluated for minimizing infant pain and stress. Methods The purpose of the study was to assess and compare ...

  16. Geometric Analysis of the Conformal Camera for Intermediate-Level Vision and Perisaccadic Perception

    OpenAIRE

    Turski, Jacek

    2009-01-01

    A binocular system developed by the author in terms of projective Fourier transform (PFT) of the conformal camera, which numerically integrates the head, eyes, and visual cortex, is used to process visual information during saccadic eye movements. Although we make three saccades per second at the eyeball's maximum speed of 700 deg/sec, our visual system accounts for these incisive eye movements to produce a stable percept of the world. This visual constancy is maintained by neuronal receptive...

  17. Prism therapy and visual rehabilitation in homonymous visual field loss.

    LENUS (Irish Health Repository)

    O'Neill, Evelyn C

    2011-02-01

    Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment.

  18. Traumatic avulsion of extraocular muscles: case reports

    Directory of Open Access Journals (Sweden)

    Nilza Minguini

    2013-04-01

    Full Text Available We described the clinical, surgical details and results (motor and sensory of the retrieving procedure of traumatically avulsed muscles in three patients with no previous history of strabismus or diplopia seen in the Department of Ophthalmology, State University of Campinas, Brazil. The slipped muscle portion was reinserted at the original insertion and under the remaining stump, which was sutured over the reinserted muscle. For all three cases there was recovery of single binocular vision and stereopsis.

  19. Surrounding Moving Obstacle Detection for Autonomous Driving Using Stereo Vision

    OpenAIRE

    Hao Sun; Huanxin Zou; Shilin Zhou; Cheng Wang; Naser El-Sheimy

    2013-01-01

    Detection and tracking surrounding moving obstacles such as vehicles and pedestrians are crucial for the safety of mobile robotics and autonomous vehicles. This is especially the case in urban driving scenarios. This paper presents a novel framework for surrounding moving obstacles detection using binocular stereo vision. The contributions of our work are threefold. Firstly, a multiview feature matching scheme is presented for simultaneous stereo correspondence and motion correspondence searc...

  20. Visual acuity in unilateral cataract.

    OpenAIRE

    Thompson, D. A.; Møller, H; Russell-Eggitt, I.; Kriss, A

    1996-01-01

    BACKGROUND: Patching the fellow eye in infancy is a well recognised therapy to encourage visual development in the lensectomised eye in cases of unilateral congenital cataract. The possibility of iatrogenic deficits of the fellow eye was investigated by comparing the vision of these patients with untreated unilateral patients and binocularly normal controls. METHODS: Sweep visual evoked potentials (VEPs) offer a rapid and objective method for estimating grating acuity. Sweep VEPs were used to...

  1. Early surgery for infantile esotropia

    OpenAIRE

    Shirabe, H.; Mori, Y; Dogru, M.; M. Yamamoto

    2000-01-01

    AIM—To investigate the postoperative eye alignment and binocular visual function after early surgery for infantile esotropia.
METHODS—Both the postoperative eye position and stereopsis were reviewed using the Titmus stereo test in nine patients who received uniocular medial rectus recession and lateral rectus resection under general anaesthesia before 8 months of age and were followed up for a minimum of 4 years.
RESULTS—Orthophoria was attained in three cases, whereas esotropia was found in ...

  2. A quantitative analysis of eye movement characteristics during the cover test

    OpenAIRE

    Barnard, N. A. S.

    1999-01-01

    The cover test is probably the most widely used clinical test of oculomotor status. It is surprising therefore, that there has been only one previous study which has attempted to provide a quantitative analysis of the eye movements during the test. There is also a dearth of information concerning the relationship between eye movements during the cover test and symptomatology and the correlation between cover test results and the outcome of other tests of binocular function. For the investigat...

  3. A Study of Essential Infantile Esotropia.

    OpenAIRE

    Sonam Patel; Snehal Ganatra; Kalpit Shah; Alka Shah; Kamini Audich; Praveen Saluja

    2015-01-01

    Introduction: Essential infantile esotropia is an entity in squint that requires particular attention because of its varied etiology and variable associated findings and that it most of the times requires early surgical intervention. Aims and Objectives: Our aim is to study incidence of occurrence, associated findings and binocular status of these patients. Materials and Methods: This is a retrospective study of 50 cases of Essential infantile esotropia who attended squint clinic of a tertiar...

  4. Ocular Stability in Three-Dimensional Space

    OpenAIRE

    Dits, Joyce

    2014-01-01

    markdownabstract__abstract__ During natural movement, we visually orient ourselves continuously to objects in our environment that are located in different directions and at different viewing distances from our body. Since humans have their eyes placed frontally, we have the ability to look at these objects using combined images of two eyes. This is called binocular vision. Visual information that enters each eye remains segregated in the primary pathways up to the visual cortex. In the prima...

  5. Measurement of Strabismic Angle Using the Distance Krimsky Test

    OpenAIRE

    Joo, Kwang Sic; Koo, Hyun; Moon, Nam Ju

    2013-01-01

    Purpose To evaluate the correlation of the distance Krimsky test and the alternate prism cover test (APCT) for the distance deviation in patients with horizontal strabismus. Methods Forty patients with horizontal strabismus (20 esotropia and 20 exotropia) were included in this study. Patients with a variable angle of deviation, vertical angle over 5 prism diopters, impaired binocular vision, or poor cooperation were excluded. We instructed the patient to look a target 6 meters away, and appli...

  6. A disinhibitory microcircuit initiates critical period plasticity in visual cortex

    OpenAIRE

    Kuhlman, Sandra J.; Olivas, Nicholas D.; Tring, Elaine; Ikrar, Taruna; Xu, Xiangmin; Trachtenberg, Joshua T.

    2013-01-01

    Early sensory experience instructs the maturation of neural circuitry in cortex 1,2 . This has been extensively studied in the primary visual cortex where loss of vision to one eye permanently degrades cortical responsiveness to that eye 3,4 , a phenomenon known as ocular dominance plasticity (ODP). Cortical inhibition mediates this process 4-6 , but the precise role of specific classes of inhibitory neurons in ODP is controversial. Here we report that evoked firing rates of binocular excitat...

  7. Fast-spiking interneurons have an initial orientation bias that is lost with vision

    OpenAIRE

    Kuhlman, Sandra J.; Tring, Elaine; Trachtenberg, Joshua T.

    2011-01-01

    We find that following eye opening fast-spiking parvalbumin-positive GABAergic interneurons in mice have well-defined orientation tuning preferences and that subsequent visual experience broadens this tuning. Broad inhibitory tuning is not required for the developmental sharpening of excitatory tuning, but does precede binocular matching of orientation tuning. We propose that the experience-dependent broadening of inhibition is a novel candidate for opening the critical period.

  8. Fast-spiking interneurons have an initial orientation bias that is lost with vision

    Science.gov (United States)

    Kuhlman, Sandra J.; Tring, Elaine; Trachtenberg, Joshua T.

    2011-01-01

    We find that following eye opening fast-spiking parvalbumin-positive GABAergic interneurons in mice have well-defined orientation tuning preferences and that subsequent visual experience broadens this tuning. Broad inhibitory tuning is not required for the developmental sharpening of excitatory tuning, but does precede binocular matching of orientation tuning. We propose that the experience-dependent broadening of inhibition is a novel candidate for opening the critical period. PMID:21750548

  9. Metamorphopsia assessment before and after vitrectomy for macular hole

    DEFF Research Database (Denmark)

    Krøyer, Kristian; Christensen, Ulrik; la Cour, Morten; Larsen, Michael

    2009-01-01

    PURPOSE: To evaluate the degree of metamorphopsia in 42 patients before and 6 months after vitrectomy for idiopathic unilateral macular hole. METHODS: Semicircular test and reference stimuli of variable diameters were applied in a binocular test that measured interocular size disparity in patient...... related to the degree of preoperative disparity in spatial projection between receptive units with a shared perceptual projection in visual space in the two eyes. (ClinicalTrials.gov number, NCT00302328.)....

  10. Dolomitization and silicification in low-energy lacustrine carbonates (Paleogene, Madrid Basin, Spain)

    OpenAIRE

    Bustillo Revuelta, María Ángeles; Arribas Mocoroa, María Eugenia; Bustillo Revuelta, Manuel

    2002-01-01

    Repetitive sequences of carbonate deposits, occurrence include in the lower part of the Paleogene Carbonate Unit (northeast border of the Madrid Basin), have been studied, defining regressive lacustrine sequences and early diagenetic processes. Binocular microscopic examination, scanning electron microscopic/energy dispersive X-ray observations, and X-ray diffraction analyses joint to isotopic studies (d18O and d13C) have been used to characterise the facies and environments. The seq...

  11. Visual function after penetrating keratoplasty for keratoconus: a prospective longitudinal evaluation

    OpenAIRE

    Brahma, A.; Ennis, F.; Harper, R.; Ridgway, A.; Tullo, A

    2000-01-01

    AIMS—To evaluate visual function and vision specific health status in patients undergoing penetrating keratoplasty for keratoconus.
METHODS—A prospective longitudinal study measuring logMAR visual acuity, contrast sensitivity, disability glare, binocular visual field, stereoacuity, and subjective visual function (VF-14) was conducted on 18 patients with keratoconus undergoing penetrating keratoplasty (PK), including six patients who had already had PK in the fellow eye. Data were collected pr...

  12. Improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery

    OpenAIRE

    Elliott, D; Patla, A.; Bullimore, M.

    1997-01-01

    AIMS—To determine the improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery.
METHODS—Clinical vision (monocular and binocular high and low contrast visual acuity, contrast sensitivity, and disability glare), functional vision (face identity and expression recognition, reading speed, word acuity, and mobility orientation), and perceived visual disability (Activities of Daily Vision Scale) were measured in 25 subjects before a...

  13. Onset rivalry: the initial dominance phase is independent of ongoing perceptual alternations

    OpenAIRE

    Jody eStanley; Jason eForte; Patrick eCavanagh; Olivia eCarter

    2011-01-01

    Binocular rivalry has been used to study a wide range of visual processes, from the integration of low-level features to the selection of signals that reach awareness. However, many of these studies do not distinguish between early and late phases of rivalry. There is clear evidence that the ‘onset’ stage of rivalry is characterized by stable, yet idiosyncratic biases that are independent of the subsequent alternations and perceptual biases experienced during sustained rivalry. Low-level stim...

  14. Nonlinear SSVEP responses are sensitive to the perceptual binding of visual hemifields during conventional ‘eye’ rivalry and interocular ‘percept’ rivalry

    OpenAIRE

    Sutoyo, David; Srinivasan, Ramesh

    2008-01-01

    We conducted behavioral and EEG experiments to identify physiological correlates of perceptual binding during two types of binocular rivalry: (1) conventional ‘eye’ rivalry where perception alternates between the two monocular images presented one to each eye and (2) interocular ‘percept’ rivalry, where perception alternates between percepts formed by grouping complementary hemifields one from each eye. We employed ‘frequency-tagging’ by flickering a grating in each hemifield of each eye at d...

  15. Attention modulation of stimulus rivalry under swapping paradigm

    OpenAIRE

    Doualot, Audrey; Simard, Mathieu; Saint-Amour, Dave

    2014-01-01

    Stimulus rivalry refers to the sustained periods of perceptual dominance that occur when different visual stimuli are swapped at a regular rate between eyes. This phenomenon is thought to involve mainly eye-independent mechanisms. Although several studies have reported that attention can increase image predominance in conventional binocular rivalry, it is unknown whether attention can specifically modulate stimulus rivalry. We addressed this question and manipulated the spatial characteristic...

  16. Temporal Analysis of Image-Rivalry Suppression

    OpenAIRE

    Rishi Bhardwaj; Robert P. O'shea

    2012-01-01

    During binocular rivalry, perception alternates between two different images presented one to each eye. At any moment, one image is visible, dominant, while the other is invisible, suppressed. Alternations in perception during rivalry could involve competition between eyes, eye-rivalry, or between images, image-rivalry, or both. We measured response criteria, sensitivities, and thresholds to brief contrast increments to one of the rival stimuli in conventional rivalry displays and in a displa...

  17. Sensory exotropia subsequent to senile cataract

    OpenAIRE

    Lou, Ding-hua; Xu, Ye-sheng; Yu-min LI

    2005-01-01

    To evaluate the phacoemulsification and intraocular lens implantation in patients with sensory exotropia subsequent to senile cataract. The authors prospectively studied the role of phacoemulsification and intraocular lens implantation on 25 patients by observing visual acuity, ocular alignment, binocular vision and diplopia pre-, 1 month post- and 3 months post-operation. The patients underwent follow-up for three months. Postoperatively, one patient had a corrected visual acuity of 20/50, a...

  18. New stereoscopic video shooting rule based on stereoscopic distortion parameters and comfortable viewing zone

    OpenAIRE

    Chen, Wei(Department of Physics, State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, 100871, China); Fournier, Jérôme; Barkowsky, Marcus; Le Callet, Patrick

    2011-01-01

    Human binocular depth perception, the most important element brought by 3DTV, is proved to be closely connected to not only the content acquisition (camera focal length, camera baseline and etc.) but also the viewing environment (viewing distance, screen size and etc.). Conventional 3D stereography rule in the literature usually consider the general viewing condition and basic human factors to guide the content acquisition, such as assuming human inter-pupil baseline as the maximum disparity....

  19. Functional morphology and integration of corvid skulls – a 3D geometric morphometric approach

    OpenAIRE

    Gunz Philipp; Frahnert Sylke; Asbahr Kolja; Kulemeyer Christoph; Bairlein Franz

    2009-01-01

    Abstract Background Sympatric corvid species have evolved differences in nesting, habitat choice, diet and foraging. Differences in the frequency with which corvid species use their repertoire of feeding techniques is expected to covary with bill-shape and with the frontal binocular field. Species that frequently probe are expected to have a relatively longer bill and more sidewise oriented orbits in contrast to species that frequently peck. We tested this prediction by analyzing computed tom...

  20. Tumor Necrosis Factor-α mediates one component of competitive, experience-dependent plasticity in developing visual cortex

    OpenAIRE

    Kaneko, Megumi; Stellwagen, David; Malenka, Robert C.; Stryker, Michael P.

    2008-01-01

    Rapid, experience-dependent plasticity in developing visual cortex is thought to be competitive. After monocular visual deprivation, the reduction in response of binocular neurons to one eye is matched by a corresponding increase to the other. Chronic optical imaging in wild type and mutant mice deficient in TNFα reveals similar initial losses of response to the deprived eye, but the subsequent increase in response to the open eye is absent in the mutant animals. This mutation also blocks hom...

  1. Grazing Habitat of the Rusa Deer (Cervus timorensis) in the Upland Kebar, Manokwari

    OpenAIRE

    AGUSTINA YOHANA SETYARINI AROBAYA; FREDDY PATTISELANNO

    2009-01-01

    The general objective of the study was to provide current information on grassland communities as deer habitat and its future development plan for a sustainable forage management in upland Kebar, Papua. Quantitative estimation of forage production was carried out by measuring a biomass harvest in fresh weight bases, while occasional observations on ranging deer were done within habitat range with the aid of 7x50 binoculars verified by actual visitation of grazed area. The study indicated that...

  2. Comparison of lea gratings with cardiff acuity cards for vision testing of preverbal children

    Directory of Open Access Journals (Sweden)

    Kruti H Mody

    2012-01-01

    Full Text Available Aims: To create a normative data for lea grating (LG in the Indian population and to compare LG with Cardiff Acuity Card (CAC. Settings and Design: Normative Data was acquired from normal children between 6 months-3 years coming to the ′Immunisation Clinic′ and ′Well-Baby Clinic′ at a Civil Hospital. To compare LG with CAC, normal and amblyopic children between 6 months-3 years were evaluated, Materials and Methods: Monocular and binocular visual acuity (VA was measured using LG and then CAC. VA and time taken to perform the test were compared. Statistical Analysis Used: Pearson′s Correlation Coefficient to compare VA and Student paired t-test (significance P<0.005 to compare time. Results: Two standard deviations of VA of 100 normal children overlapped with that published by Lea. Of the 30 amblyopic children aged 18.32 ± 10.5 months (2-36, 18 were females. VA was 0.95 ± 0.3 logMAR (0.7-1.2 and 1.0 ± 0.6 logMAR (0.5-2.1 binocularly and 1.32 ± 0.08 logMAR (0.2-0.6 and 1.15 ± 0.15 logMAR (0.88-1.48 monocularly on CAC and LG respectively. Pearson′s correlation coefficient was 0.98 and 0.63 for binocular and monocular assessment respectively. Time taken to perform LG monocularly and binocularly was significantly less (P<0.001 than CAC. Conclusion: Normative data acquired in Indian pre-verbal children is similar to that published by Lea. Though VA by CAC is better than LG, the two tests are comparable.

  3. Vector disparity sensor with vergence control for active vision systems

    OpenAIRE

    Eduardo Ros; Francisco Barranco; Javier Diaz; Sabatini, Silvio P; Agostino Gibaldi

    2012-01-01

    This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that ac...

  4. Ultrasonography-guided scleral buckle retinopexy and cryotherapy: case report Retinopexia com "buckle" escleral e crioterapia guiada por ultrassom: relato de caso

    OpenAIRE

    Daniel da Rocha Lucena; Jefferson Augusto Santana Ribeiro; Marco Sérgio Pinto Alves Folgosa; Levy da Rocha Lucena; Rodrigo Jorge

    2009-01-01

    If the ocular media are clear, indirect binocular ophthalmoscopy allows retinal detachment and retinal tear identification and treatment under direct visualization. However, if opacities are present preventing direct fundus examination, ultrasonography becomes the most important tool for evaluating the posterior segment. In addition, ultrasonography can be useful in retinal tear treatment by guiding cryotherapy. In this article we describe a rhegmatogenous retinal detachment treatment techniq...

  5. Albinism: Particular Attention to the Ocular Motor System

    OpenAIRE

    Richard W Hertle

    2013-01-01

    The purpose of this report is to summarize an understanding of the ocular motor system in patients with albinism. Other than the association of vertical eccentric gaze null positions and asymmetric, (a) periodic alternating nystagmus in a large percentage of patients, the ocular motor system in human albinism does not contain unique pathology, rather has "typical" types of infantile ocular oscillations and binocular disorders. Both the ocular motor and afferent visual system are affected to v...

  6. Imported resources - gas/oil

    Energy Technology Data Exchange (ETDEWEB)

    Jakob, K. [MOL Hungarian Oil and Gas Company, Budapest (Hungary)

    1995-12-01

    The goal of this presentation is to provide information on issues of crude oil and natural gas supply at a conference addressing the problems of energy in Eastern and Central Europe. Although this can inevitably be performed through the {open_quotes}binoculars{close_quotes} of the petroleum sector of my country, I will try to present the issues and challenges that are thought to be characteristic in general for the region.

  7. Vision in albinism.

    OpenAIRE

    Summers, C G

    1996-01-01

    PURPOSE: The purpose of this investigation was to study vision in albinism from 3 perspectives: first, to determine the characteristics of grating acuity development in children with albinism; second, to study the effect of illumination on grating acuity; and third, to define the effect of melanin pigment in the macula on visual acuity. METHODS: I. Binocular and monocular grating acuity was measured with the acuity card procedure in 40 children with albinism during the first 3 years of life. ...

  8. Neural architectures for stereo vision.

    Science.gov (United States)

    Parker, Andrew J; Smith, Jackson E T; Krug, Kristine

    2016-06-19

    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'. PMID:27269604

  9. Reaching into Pictorial Spaces

    Science.gov (United States)

    Volcic, Robert; Vishwanath, Dhanraj; Domini, Fulvio

    2014-02-01

    While binocular viewing of 2D pictures generates an impression of 3D objects and space, viewing a picture monocularly through an aperture produces a more compelling impression of depth and the feeling that the objects are "out there", almost touchable. Here, we asked observers to actually reach into pictorial space under both binocular- and monocular-aperture viewing. Images of natural scenes were presented at different physical distances via a mirror-system and their retinal size was kept constant. Targets that observers had to reach for in physical space were marked on the image plane, but at different pictorial depths. We measured the 3D position of the index finger at the end of each reach-to-point movement. Observers found the task intuitive. Reaching responses varied as a function of both pictorial depth and physical distance. Under binocular viewing, responses were mainly modulated by the different physical distances. Instead, under monocular viewing, responses were modulated by the different pictorial depths. Importantly, individual variations over time were minor, that is, observers conformed to a consistent pictorial space. Monocular viewing of 2D pictures thus produces a compelling experience of an immersive space and tangible solid objects that can be easily explored through motor actions.

  10. Prism-based single-camera system for stereo display

    Science.gov (United States)

    Zhao, Yue; Cui, Xiaoyu; Wang, Zhiguo; Chen, Hongsheng; Fan, Heyu; Wu, Teresa

    2016-06-01

    This paper combines the prism and single camera and puts forward a method of stereo imaging with low cost. First of all, according to the principle of geometrical optics, we can deduce the relationship between the prism single-camera system and dual-camera system, and according to the principle of binocular vision we can deduce the relationship between binoculars and dual camera. Thus we can establish the relationship between the prism single-camera system and binoculars and get the positional relation of prism, camera, and object with the best effect of stereo display. Finally, using the active shutter stereo glasses of NVIDIA Company, we can realize the three-dimensional (3-D) display of the object. The experimental results show that the proposed approach can make use of the prism single-camera system to simulate the various observation manners of eyes. The stereo imaging system, which is designed by the method proposed by this paper, can restore the 3-D shape of the object being photographed factually.

  11. Vision Health-Related Quality of Life in Chinese Glaucoma Patients

    Directory of Open Access Journals (Sweden)

    Lei Zuo

    2015-01-01

    Full Text Available This cross-sectional study evaluated VRQOL in Chinese glaucoma patients and the potential factors influencing VRQOL. The VRQOL was assessed using the Chinese-version low vision quality of life questionnaire. Visual field loss was classified by the Hodapp-Parrish-Anderson method. The correlations of VRQOL to the best corrected visual acuity and the VF loss were investigated. The potential impact factors to VRQOL of glaucoma patients were screened by single factor analysis and were further analyzed by multiple regression analysis. There were significant differences in VRQOL scores between mild VF loss group and moderate VF loss group, moderate VF loss group and severe VF loss group, and mild VF loss group and severe VF loss group according to the better eye. In multiple linear regression, the binocular weighted average BCVA significantly affected the VRQOL scores. Binocular MD was the second influencing factor. In logistic regression, binocular severe VF loss and stroke were significantly associated with abnormal VRQOL. Education was the next influencing factor. This study showed that visual acuity correlated linearly with VRQOL, and VF loss might reach a certain level, correlating with abnormal VRQOL scores. Stroke was significantly associated with abnormal VRQOL.

  12. Gaze-dependent phoria and vergence adaptation.

    Science.gov (United States)

    Dysli, Muriel; Abegg, Mathias

    2016-02-01

    Incomitance is a condition with gaze-dependent deviations of ocular alignment and is common in strabismus patients. The physiological mechanisms that maintain equal horizontal ocular alignment in all gaze directions (concomitance) in healthy individuals are poorly explored. We investigate adaptive processes in the vergence system that are induced by horizontal incomitant vergence stimuli (stimuli that require a gaze-dependent vergence response in order to re-establish binocular single vision). We measured horizontal vergence responses elicited after healthy subjects shifted their gaze from a position that required no vergence to a position that required convergence. Repetitive saccades into a position with a convergence stimulus rapidly decreased phoria (defined as the deviation of ocular alignment in the absence of a binocular stimulus). This change of phoria was present in all viewing directions (from 0° to 0.86° ± 0.40°, p convergence stimulus (from 0.26° ± 0.13° to 1.39° ± 0.33°, p eye movements and also in pursuit-vergence eye movements. Thus, acute horizontal, gaze-dependent changes of vergence, such as may be encountered in new onset strabismus due to paralysis, can rapidly increase vergence velocity and decrease latency. Gaze-specific (concomitant) and gaze-independent (incomitant) phoria levels will adapt. These early adaptive processes increase the efficacy of binocular vision and maintain good ocular alignment in all directions of gaze. PMID:26830708

  13. Dynamics of the near response under natural viewing conditions with an open-view sensor.

    Science.gov (United States)

    Chirre, Emmanuel; Prieto, Pedro; Artal, Pablo

    2015-10-01

    We have studied the temporal dynamics of the near response (accommodation, convergence and pupil constriction) in healthy subjects when accommodation was performed under natural binocular and monocular viewing conditions. A binocular open-view multi-sensor based on an invisible infrared Hartmann-Shack sensor was used for non-invasive measurements of both eyes simultaneously in real time at 25Hz. Response times for each process under different conditions were measured. The accommodative responses for binocular vision were faster than for monocular conditions. When one eye was blocked, accommodation and convergence were triggered simultaneously and synchronized, despite the fact that no retinal disparity was available. We found that upon the onset of the near target, the unblocked eye rapidly changes its line of sight to fix it on the stimulus while the blocked eye moves in the same direction, producing the equivalent to a saccade, but then converges to the (blocked) target in synchrony with accommodation. This open-view instrument could be further used for additional experiments with other tasks and conditions. PMID:26504666

  14. Study of measurement and calculation of the relative amplitude of accommodation

    Science.gov (United States)

    Coloma, Pilar; Pascual, Inmaculada; de Fez, Dolores; Camps, Vicente

    2013-11-01

    Status of binocular vision is evaluated using binoculars and accommodative tests. The results of these tests allow the optometrist to decide or the type of lenses has to be prescribed or whether a vision therapy is required. The aim of this work is to check the accuracy of the measurement of the relative amplitude of accommodation. Relative accommodation amplitude assesses the ability to increase or decrease the accommodation when convergence demand is constant. The eye must be neutralized to take the measurement. Because the test is situated at a distance of 40 cm, it is considered that the convergence is 2'5 am and the accommodation 2'50 D. However, this assumption could lead to important errors in ammetropic subjects due to the eye after neutralization accommodates in the image produced by the lens forms and converges in the position of the effective binocular object [1]. Therefore, it is necessary to set measurement conditions in which the accommodative and convergence stimulus are the same for all subjects. Furthermore, the lenses added on the neutralization to determine the relative amplitude of accommodation do not correspond to the dioptric value of relaxation and stimulation of the eye accommodation. To obtain this value a more precise calculation has to be performed.

  15. Lateralization of visuospatial processing in the bottlenose dolphin (Tursiops truncatus).

    Science.gov (United States)

    Kilian, A; von Fersen, L; Güntürkün, O

    2000-12-01

    Two adult female bottlenose dolphins were tested for cerebral asymmetries in the visuospatial domain. The animals learned under binocular conditions a three-choice spatial discrimination task with three hoops positioned along a line in the middle of the tank. During a correct trial the dolphins had to swim from a starting position at the tanks wall through one of the hoops, come back to the starting position, choose another hoop, swim back to start and finally swim through the third hoop. For such a trial to be correct, the animals had to swim through all three hoops in any sequence without omitting or re-using one of them. After reaching criterion binocularly, monocular trials (one eye covered with an adherent suction cup) were introduced where the dolphins carried out the same task alternatingly under left or right eye seeing conditions. For both animals, the right eye performance was clearly superior to that of the left eye. Binocular and right eye performances were similar. As a result of the complete decussation at the optic nerve, this right eye superiority suggests a left-hemispheric dominance for the processing of visuospatial information. This is a remarkable deviation from the usual right hemisphere advantage for these kind of tasks found in different species of mammals and birds. PMID:11080552

  16. Vision screening in school children in Strzelin County

    Science.gov (United States)

    Zając, Marek

    2007-04-01

    Investigation of children vision is one of the most important tasks in pediatric medical care. According to World Health Organization screening done with rapid and simple tests should be considered as initial step of such care. Thanks to simple screening tests it is possible to identify children who probably are burden with eye problems and to distinguish them from the children with correct vision. Typical test for screening 6-years-old children (beginning their school education) includes, among others, evaluation of visual acuity for far and/or near and evaluation of binocular vision. This contribution describes the methods and results of screening program covering 21 elementary schools and 450 children in Strzelin County (Lower Silesia). Visual acuity was measured with help of SCOLATEST TM and binocular vision with RANDOM DOT E STEREOTEST. Additionally color recognition was tested with Ishihara Children Plates. The results suggest that almost 29% of investigated children have refraction error (9% being myopes and 20% being hyperopes), and 9% has problems with binocular vision.

  17. Mapping number to space in the two hemispheres of the avian brain.

    Science.gov (United States)

    Rugani, Rosa; Vallortigara, Giorgio; Regolin, Lucia

    2016-09-01

    Pre-verbal infants and non-human animals associate small numbers with the left space and large numbers with the right space. Birds and primates, trained to identify a given position in a sagittal series of identical positions, whenever required to respond on a left/right oriented series, referred the given position starting from the left end. Here, we extended this evidence by selectively investigating the role of either cerebral hemisphere, using the temporary monocular occlusion technique. In birds, lacking the corpus callosum, visual input is fed mainly to the contralateral hemisphere. We trained 4-day-old chicks to identify the 4th element in a sagittal series of 10 identical elements. At test, the series was identical but left/right oriented. Test was conducted in right monocular, left monocular or binocular condition of vision. Right monocular chicks pecked at the 4th right element; left monocular and binocular chicks pecked at the 4th left element. Data on monocular chicks demonstrate that both hemispheres deal with an ordinal (sequential) task. Data on binocular chicks indicate that the left bias is linked to a right hemisphere dominance, that allocates the attention toward the left hemispace. This constitutes a first step towards understanding the neural basis of number space mapping. PMID:27246250

  18. Brain networks underlying bistable perception.

    Science.gov (United States)

    Baker, Daniel H; Karapanagiotidis, Theodoros; Coggan, David D; Wailes-Newson, Kirstie; Smallwood, Jonathan

    2015-10-01

    Bistable stimuli, such as the Necker Cube, demonstrate that experience can change in the absence of changes in the environment. Such phenomena can be used to assess stimulus-independent aspects of conscious experience. The current study used resting state functional magnetic resonance imaging (rs-fMRI) to index stimulus-independent changes in neural activity to understand the neural architecture that determines dominance durations during bistable perception (using binocular rivalry and Necker cube stimuli). Anterior regions of the Superior Parietal Lobule (SPL) exhibited robust connectivity with regions of primary sensorimotor cortex. The strength of this region's connectivity with the striatum predicted shorter dominance durations during binocular rivalry, whereas its connectivity to pre-motor cortex predicted longer dominance durations for the Necker Cube. Posterior regions of the SPL, on the other hand, were coupled to associative cortex in the temporal and frontal lobes. The posterior SPL's connectivity to the temporal lobe predicted longer dominance during binocular rivalry. In conjunction with prior work, these data suggest that the anterior SPL contributes to perceptual rivalry through the inhibition of incongruent bottom up information, whereas the posterior SPL influences rivalry by supporting the current interpretation of a bistable stimulus. Our data suggests that the functional connectivity of the SPL with regions of sensory, motor, and associative cortex allows it to regulate the interpretation of the environment that forms the focus of conscious attention at a specific moment in time. PMID:26123379

  19. Reduced GABAergic Action in the Autistic Brain.

    Science.gov (United States)

    Robertson, Caroline E; Ratai, Eva-Maria; Kanwisher, Nancy

    2016-01-11

    An imbalance between excitatory/inhibitory neurotransmission has been posited as a central characteristic of the neurobiology of autism [1], inspired in part by the striking prevalence of seizures among individuals with the disorder [2]. Evidence supporting this hypothesis has specifically implicated the signaling pathway of the inhibitory neurotransmitter, γ-aminobutyric acid (GABA), in this putative imbalance: GABA receptor genes have been associated with autism in linkage and copy number variation studies [3-7], fewer GABA receptor subunits have been observed in the post-mortem tissue of autistic individuals [8, 9], and GABAergic signaling is disrupted across heterogeneous mouse models of autism [10]. Yet, empirical evidence supporting this hypothesis in humans is lacking, leaving a gulf between animal and human studies of the condition. Here, we present a direct link between GABA signaling and autistic perceptual symptomatology. We first demonstrate a robust, replicated autistic deficit in binocular rivalry [11], a basic visual function that is thought to rely on the balance of excitation/inhibition in visual cortex [12-15]. Then, using magnetic resonance spectroscopy, we demonstrate a tight linkage between binocular rivalry dynamics in typical participants and both GABA and glutamate levels in the visual cortex. Finally, we show that the link between GABA and binocular rivalry dynamics is completely and specifically absent in autism. These results suggest a disruption in inhibitory signaling in the autistic brain and forge a translational path between animal and human models of the condition. PMID:26711497

  20. Comparison of anisometropes with and without amblyopia

    Directory of Open Access Journals (Sweden)

    Huban Atilla

    2011-01-01

    Full Text Available Background: To compare binocular functions in amblyopic and non-amblyopic anisometropes and to investigate the possible associated factors for amblyopia development such as type of refractive error and initial age of refractive error correction. Materials and Methods: Prospectively anisometropic subjects with (n=42 and without amblyopia (n=33 were included in the study. Full ophthalmological examination including binocularity and motility was performed. Results: There was no statistically significant difference between the ages at the time of initial refractive error correction ( p0 =0.946. All of the anisometropes (100% had fusion with Worth 4-dot test and Bagolini glasses. However 81% of amblyopic subjects had fusion with Worth 4 dot test and 88.1% had normal response with Bagolini glasses. Median stereopsis was 60 sec of arc in anisometropic subjects and 400 sec of arc in amblyopes. Conclusion: Our data support that, binocular functions are well developed in anisometropes without amblyopia and initial age at correction of refractive error has no primary effect on development of amblyopia.

  1. Parameters of the human 3D gaze while observing portable autostereoscopic display: a model and measurement results

    Science.gov (United States)

    Boev, Atanas; Hanhela, Marianne; Gotchev, Atanas; Utirainen, Timo; Jumisko-Pyykkö, Satu; Hannuksela, Miska

    2012-02-01

    We present an approach to measure and model the parameters of human point-of-gaze (PoG) in 3D space. Our model considers the following three parameters: position of the gaze in 3D space, volume encompassed by the gaze and time for the gaze to arrive on the desired target. Extracting the 3D gaze position from binocular gaze data is hindered by three problems. The first problem is the lack of convergence - due to micro saccadic movements the optical lines of both eyes rarely intersect at a point in space. The second problem is resolution - the combination of short observation distance and limited comfort disparity zone typical for a mobile 3D display does not allow the depth of the gaze position to be reliably extracted. The third problem is measurement noise - due to the limited display size, the noise range is close to the range of properly measured data. We have developed a methodology which allows us to suppress most of the measurement noise. This allows us to estimate the typical time which is needed for the point-of-gaze to travel in x, y or z direction. We identify three temporal properties of the binocular PoG. The first is reaction time, which is the minimum time that the vision reacts to a stimulus position change, and is measured as the time between the event and the time the PoG leaves the proximity of the old stimulus position. The second is the travel time of the PoG between the old and new stimulus position. The third is the time-to-arrive, which is the time combining the reaction time, travel time, and the time required for the PoG to settle in the new position. We present the method for filtering the PoG outliers, for deriving the PoG center from binocular eye-tracking data and for calculating the gaze volume as a function of the distance between PoG and the observer. As an outcome from our experiments we present binocular heat maps aggregated over all observers who participated in a viewing test. We also show the mean values for all temporal

  2. Overcoming Presbyopia by Manipulating the Eyes' Optics

    Science.gov (United States)

    Zheleznyak, Leonard A.

    Presbyopia, the age-related loss of accommodation, is a visual condition affecting all adults over the age of 45 years. In presbyopia, individuals lose the ability to focus on nearby objects, due to a lifelong growth and stiffening of the eye's crystalline lens. This leads to poor near visual performance and affects patients' quality of life. The objective of this thesis is aimed towards the correction of presbyopia and can be divided into four aims. First, we examined the characteristics and limitations of currently available strategies for the correction of presbyopia. A natural-view wavefront sensor was used to objectively measure the accommodative ability of patients implanted with an accommodative intraocular lens (IOL). Although these patients had little accommodative ability based on changes in power, pupil miosis and higher order aberrations led to an improvement in through-focus retinal image quality in some cases. To quantify the through-focus retinal image quality of accommodative and multifocal IOLs directly, an adaptive optics (AO) IOL metrology system was developed. Using this system, the impact of corneal aberrations in regard to presbyopia-correcting IOLs was assessed, providing an objective measure of through-focus retinal image quality and practical guidelines for patient selection. To improve upon existing multifocal designs, we investigated retinal image quality metrics for the prediction of through-focus visual performance. The preferred metric was based on the fidelity of an image convolved with an aberrated point spread function. Using this metric, we investigated the potential of higher order aberrations and pupil amplitude apodization to increase the depth of focus of the presbyopic eye. Thirdly, we investigated modified monovision, a novel binocular approach to presbyopia correction using a binocular AO vision simulator. In modified monovision, different magnitudes of defocus and spherical aberration are introduced to each eye, thereby

  3. Clinical Course and Response to Therapy in Different Types of Amblyopia

    Directory of Open Access Journals (Sweden)

    Reşat Duman

    2013-10-01

    Full Text Available Purpose: We aimed to compare the demographic features, visual acuities before and after treatment, amblyopia and strabismus degrees and binocular visual functions in cases with anisometropic, strabismic and/or anisometropic amblyopia. Material and Method: The study included 50 anisometropic, 50 strabismic and 50 anisometropic and strabismic cases that were followed up with the diagnosis of amblyopia, in our clinic, between January 2007 - September 2010. Amblyopia criteria was defined as the best corrected visual acuity of ≤0.8 and at least 2 lines difference between the visual acuities of two eyes. Anisometropia was defined as ≥1D difference in the spherical and cylindrical value between two eyes. Results: The groups were statistically similar in means of age and sex distribution. Visual acuities in amblyopic eyes before and after treatment were also statistically similar. There were no significant difference between 3 groups in means of compliance to occlusion therapy. In anisometropic cases, anisometropic spherical values were found to have position correlation with amblyopia degree. In hypermetropic and myopic cases, a strong correlation was shown between anisometropia and amblyopia, especially in hypermetropic cases, amblyopia degree increased as the anisometropia increased. In all strabismus cases, a positive correlation between strabismus and amblyopia degrees was shown even though it was statistically insignificant. In strabismic cases, esotropia was significantly higher than exotropia. In anisometropia group, stereopsis and fusion was found to be preserved better in comparison to the strabismic cases. It was concluded that deviation had a more profound effect on binocular function loss than anisometropia. Discussion: We recommend to follow the hypermetropic anisometropic cases and especially cases with high degree strabismus and esotropia more closely. And also we emphasize that strabismus affects binocular function loss more than

  4. Evaluation of periosteal fixation of lateral rectus and partial VRT for cases of exotropic Duane retraction syndrome

    Directory of Open Access Journals (Sweden)

    Pradeep Sharma

    2014-01-01

    Full Text Available Purpose: The purpose of this study is to evaluate the lateral rectus periosteal fixation and partial vertical rectus transpositioning (VRT as treatment modalities to correct exotropic Duane retraction syndrome (Exo-DRS. Materials and Methods: Prospective interventional case study of cases of Exo-DRS with limitation of adduction. A total of 13 patients were subdivided into two groups. Six patients underwent only lateral rectus periosteal fixation (group A and seven patients also underwent partial VRT (group B. Assessment involved prism bar cover test, abduction and adduction range, extent of binocular single visual field and exophthalmometry. These tests were repeated at 1 week, 1 month and 3 months post-operatively and data analyzed. Results: The pre-operative mean values and ranges were 26.2 Δ (22-35 exotropia for group A and −21.3 Δ (14-30 exotropia for group B. The post-operative mean and range was +0.6 Δ esotropia (+20 to −8 for group A and 8 Δ (−2 to −20 exotropia for group B. Mean grade of limitation of abduction changed from −3.8 to −3.6 versus −3.6 to −2.8 and mean grade of limitation of adduction changed from −1.9 to −0.7 versus −1.5 to −0.5 in the groups A and B respectively. Mean binocular single visual field changed from 14.7° to 23.3° in group A and 11.8° to 26.4° in the group B respectively. Conclusion: Lateral rectus periosteal fixation is an effective surgery to correct the exodeviation, anomalous head posture and improving adduction in Exo-DRS and partial VRT in addition is effective in improving abduction and binocular single visual fields.

  5. Reduced vergence adaptation is associated with a prolonged output of convergence accommodation in convergence insufficiency.

    Science.gov (United States)

    Sreenivasan, Vidhyapriya; Bobier, William R

    2014-07-01

    Convergence insufficiency (CI) is a developmental visual anomaly defined clinically by a reduced near point of convergence, a reduced capacity to view through base-out prisms (fusional convergence); coupled with asthenopic symptoms typically blur and diplopia. Experimental studies show reduced vergence parameters and tonic adaptation. Based upon current models of accommodation and vergence, we hypothesize that the reduced vergence adaptation in CI leads to excessive amounts of convergence accommodation (CA). Eleven CI participants (mean age=17.4±2.3 years) were recruited with reduced capacity to view through increasing magnitudes of base out (BO) prisms (mean fusional convergence at 40 cm=12±0.9Δ). Testing followed our previous experimental design for (n=11) binocularly normal adults. Binocular fixation of a difference of Gaussian (DoG) target (0.2 cpd) elicited CA responses during vergence adaptation to a 12Δ BO. Vergence and CA responses were obtained at 3 min intervals over a 15 min period and time course were quantified using exponential decay functions. Results were compared to previously published data on eleven binocular normals. Eight participants completed the study. CI's showed significantly reduced magnitude of vergence adaptation (CI: 2.9Δ vs. normals: 6.6Δ; p=0.01) and CA reduction (CI=0.21 D, Normals=0.55 D; p=0.03). However, the decay time constants for adaptation and CA responses were not significantly different. CA changes were not confounded by changes in tonic accommodation (Change in TA=0.01±0.2D; p=0.8). The reduced magnitude of vergence adaptation found in CI patients resulting in higher levels of CA may potentially explain their clinical findings of reduced positive fusional vergence (PFV) and the common symptom of blur. PMID:24759573

  6. Further evidence of an early critical period in the development of the cat's dorsal lateral geniculate nucleus.

    Science.gov (United States)

    Sherman, S M; Wilson, J R

    1981-03-01

    The concept of an early postnatal critical period of development for the lateral geniculate nucleus was assessed by determining in adult cats whether previously established properties of geniculate neurons could be altered by varying the cat's visual experience. The analysis was limited to lamina A1 and the binocular segment of lamina A, and the properties studied were the percentage of physiologically recorded Y-cells and cell soma size. Eleven experimental cats in four groups were studied, and three cats reared normally plus three cats reared with continuous monocular lid suture served as controls. Two cats raised first with monocular suture followed by a prolonged period in adulthood with both eyes open had cell size distributions and Y-cell proportions that were indistinguishable from cats raised with continuous monocular suture. Four cats raised first with one eye sutured underwent a reverse suture procedure in adulthood (i.e., the originally sutured eye opened and the other closed) and were maintained in this fashion for a prolonged period. These cats also had geniculate cell size distributions and Y-cell proportions that were indistinguishable from cats raised with continuous monocular suture. Two cats were raised first with binocular suture followed by a prolonged period in adulthood with one eye opened. Their geniculate cell size distributions and Y-cell proportions showed no effect on the adult monocular deprivation and were indistinguishable from previously published data concerning cats raised with continuous binocular suture. Finally, three normally raised cats underwent a prolonged period of monocular suture in adulthood. Their geniculate cell size distributions and Y-cell proportions showed no effects on the adult monocular deprivation. From these data, we conclude that an early critical period of development occurs for geniculate cell sizes and Y-cell proportions. Adult visual environments, whether normal or abnormal, had no detectable effect on

  7. How the Venetian Blind Percept Emergesfrom the Laminar Cortical Dynamics of 3D Vision

    Directory of Open Access Journals (Sweden)

    Stephen eGrossberg

    2014-08-01

    Full Text Available The 3D LAMINART model of 3D vision and figure-ground perception is used to explain and simulate a key example of the Venetian blind effect and show how it is related to other well-known perceptual phenomena such as Panum's limiting case. The model shows how identified neurons that interact in hierarchically organized laminar circuits of the visual cortex can simulate many properties of 3D vision percepts, notably consciously seen surface percepts, which are predicted to arise when filled-in surface representations are integrated into surface-shroud resonances between visual and parietal cortex. The model describes how monocular and binocular oriented filtering interacts with later stages of 3D boundary formation and surface filling-in in the lateral geniculate nucleus (LGN and cortical areas V1, V2, and V4. It proposes how interactions between layers 4, 3B, and 2/3 in V1 and V2 contribute to stereopsis, and how binocular and monocular information combine to form 3D boundary and surface representations. The model suggests how surface-to-boundary feedback from V2 thin stripes to pale stripes enables computationally complementary boundary and surface formation properties to generate a single consistent percept, eliminate redundant 3D boundaries, and trigger figure-ground perception. The model also shows how false binocular boundary matches may be eliminated by Gestalt grouping properties. In particular, a disparity filter, which helps to solve the Correspondence Problem by eliminating false matches, is predicted to be realized as part of the boundary grouping process in layer 2/3 of cortical area V2. The model has been used to simulate the consciously seen 3D surface percepts in 18 psychophysical experiments. These percepts include the Venetian blind effect, Panum's limiting case, contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, stereopsis with polarity

  8. A laminar cortical model of stereopsis and 3D surface perception: closure and da Vinci stereopsis.

    Science.gov (United States)

    Cao, Yongqiang; Grossberg, Stephen

    2005-01-01

    A laminar cortical model of stereopsis and 3D surface perception is developed and simulated. The model describes how monocular and binocular oriented filtering interact with later stages of 3D boundary formation and surface filling-in in the LGN and cortical areas V1, V2, and V4. It proposes how interactions between layers 4, 3B, and 2/3 in V1 and V2 contribute to stereopsis, and how binocular and monocular information combine to form 3D boundary and surface representations. The model includes two main new developments: (1) It clarifies how surface-to-boundary feedback from V2 thin stripes to pale stripes helps to explain data about stereopsis. This feedback has previously been used to explain data about 3D figure-ground perception. (2) It proposes that the binocular false match problem is subsumed under the Gestalt grouping problem. In particular, the disparity filter, which helps to solve the correspondence problem by eliminating false matches, is realized using inhibitory interneurons as part of the perceptual grouping process by horizontal connections in layer 2/3 of cortical area V2. The enhanced model explains all the psychophysical data previously simulated by Grossberg and Howe (2003), such as contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, Panum's limiting case, the Venetian blind illusion, stereopsis with polarity-reversed stereograms, and da Vinci stereopsis. It also explains psychophysical data about perceptual closure and variations of da Vinci stereopsis that previous models cannot yet explain. PMID:16312095

  9. Stereopsis and 3D surface perception by spiking neurons in laminar cortical circuits: a method for converting neural rate models into spiking models.

    Science.gov (United States)

    Cao, Yongqiang; Grossberg, Stephen

    2012-02-01

    A laminar cortical model of stereopsis and 3D surface perception is developed and simulated. The model shows how spiking neurons that interact in hierarchically organized laminar circuits of the visual cortex can generate analog properties of 3D visual percepts. The model describes how monocular and binocular oriented filtering interact with later stages of 3D boundary formation and surface filling-in in the LGN and cortical areas V1, V2, and V4. It proposes how interactions between layers 4, 3B, and 2/3 in V1 and V2 contribute to stereopsis, and how binocular and monocular information combine to form 3D boundary and surface representations. The model suggests how surface-to-boundary feedback from V2 thin stripes to pale stripes helps to explain how computationally complementary boundary and surface formation properties lead to a single consistent percept, eliminate redundant 3D boundaries, and trigger figure-ground perception. The model also shows how false binocular boundary matches may be eliminated by Gestalt grouping properties. In particular, the disparity filter, which helps to solve the correspondence problem by eliminating false matches, is realized using inhibitory interneurons as part of the perceptual grouping process by horizontal connections in layer 2/3 of cortical area V2. The 3D sLAMINART model simulates 3D surface percepts that are consciously seen in 18 psychophysical experiments. These percepts include contrast variations of dichoptic masking and the correspondence problem, the effect of interocular contrast differences on stereoacuity, Panum's limiting case, the Venetian blind illusion, stereopsis with polarity-reversed stereograms, da Vinci stereopsis, and perceptual closure. The model hereby illustrates a general method of unlumping rate-based models that use the membrane equations of neurophysiology into models that use spiking neurons, and which may be embodied in VLSI chips that use spiking neurons to minimize heat production. PMID

  10. Pain and stress assessment after retinopathy of prematurity screening examination: Indirect ophthalmoscopy versus digital retinal imaging

    Directory of Open Access Journals (Sweden)

    Moral-Pumarega M

    2012-08-01

    Full Text Available Abstract Background Increasingly, neonatal clinics seek to minimize painful experiences and stress for premature infants. Fundoscopy performed with a binocular indirect ophthalmoscope is the reference examination technique for screening of retinopathy of prematurity (ROP, and it is associated with pain and stress. Wide-field digital retinal imaging is a recent technique that should be evaluated for minimizing infant pain and stress. Methods The purpose of the study was to assess and compare the impact of using a binocular indirect ophthalmoscope (BIO, or wide-field digital retinal imaging (WFDRI on pain and stress in infants undergoing ROP screening examination. This was a comparative evaluation study of two screening procedures. Ophthalmologic examinations (N = 70 were performed on 24 infants with both BIO and WFDRI. Pain assessments were performed with two specific neonatal scales (Crying, requires oxygen, increased vital signs, expression and sleeplessness, CRIES and, Premature infant pain profile, PIPP just prior to the examination, and 30 seconds, 1 hour, and 24 hours later after ending the examination. Results Changes over time were significantly different between BIO and WFDRI with both scales (PIPP score, p = .007, and CRIES score, p = .001. Median PIPP score (interquartile interval at baseline was 4 (3–5. At 30 seconds the score was 8 (6–9 for BIO and 6 (5–7 for WFDRI, respectively. The increase in PIPP score between baseline and 30 seconds was significantly lower with WFDRI (p = .006. The median increase in CRIES score from baseline to 30 seconds was 1 point lower for WFDRI than for BIO (p  Conclusions A transient short-term pain and stress response occurs with both BIO and WFDRI. Infants examined for screening of ROP with digital retinal imaging present less pain and stress at 30 seconds following completion of the exam when compared with binocular indirect ophthalmoscopy.

  11. Prism therapy and visual rehabilitation in homonymous visual field loss.

    LENUS (Irish Health Repository)

    O'Neill, Evelyn C

    2012-02-01

    PURPOSE: Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment. METHODS: Twelve patients with acquired, documented HVFD were eligible to be included. All patients underwent specific vision-targeted, health-related QOL questionnaire and monocular and binocular Goldmann perimetry before commencing prism therapy. Patients were fitted with monocular prisms on the side of the HVFD with the base-in the direction of the field defect creating a peripheral optical exotropia and field expansion. After the treatment period, QOL questionnaires and perimetry were repeated. RESULTS: Twelve patients were included in the treatment group, 10 of whom were included in data analysis. Overall, there was significant improvement within multiple vision-related, QOL functioning parameters, specifically within the domains of general health (p < 0.01), general vision (p < 0.05), distance vision (p < 0.01), peripheral vision (p < 0.05), role difficulties (p < 0.05), dependency (p < 0.05), and social functioning (p < 0.05). Visual field expansion was shown when measured monocularly and binocularly during the study period in comparison with pretreatment baselines. CONCLUSIONS: Patients with HVFD demonstrate decreased QOL. Monocular sector prisms can improve the QOL and expand the visual field in these patients.

  12. Comparing the fixational and functional preferred retinal location in a pointing task.

    Science.gov (United States)

    Sullivan, Brian; Walker, Laura

    2015-11-01

    Patients with central vision loss (CVL) typically adopt eccentric viewing strategies using a preferred retinal locus (PRL) in peripheral retina. Clinically, the PRL is defined monocularly as the area of peripheral retina used to fixate small stimuli. It is not clear if this fixational PRL describes the same portion of peripheral retina used during dynamic binocular eye-hand coordination tasks. We studied this question with four participants each with a unique CVL history. Using a scanning laser ophthalmoscope, we measured participants' monocular visual fields and the location and stability of their fixational PRLs. Participants' monocular and binocular visual fields were also evaluated using a computer monitor and eye tracker. Lastly, eye-hand coordination was tested over several trials where participants pointed to and touched a small target on a touchscreen monitor. Trials were blocked and carried out monocularly and binocularly, with a target appearing at 5° or 15° from screen center, in one of 8 locations. During pointing, our participants often exhibited long movement durations, an increased number of eye movements and impaired accuracy, especially in monocular conditions. However, these compensatory changes in behavior did not consistently worsen when loci beyond the fixational PRL were used. While fixational PRL size, location and fixation stability provide a necessary description of behavior, they are not sufficient to capture the pointing PRL used in this task. Generally, patients use a larger portion of peripheral retina than one might expect from measures of the fixational PRL alone, when pointing to a salient target without time constraints. While the fixational and pointing PRLs often overlap, the fixational PRL does not predict the large area of peripheral retina that can be used. PMID:26440864

  13. Evaluation of the correctness of a 3D recording device for mandibular functional movement in laboratory

    Science.gov (United States)

    Zhao, Tian; Sui, Huaxin; Yang, Huifang; Wang, Yong; Sun, Yuchun

    2015-07-01

    Objectives: To quantitatively evaluate the correctness of a computer binocular vision mandibular 3D trajectory recording device. Methods: A specialized target shooting paper was neatly pasted on a high-precision three-axis electronic translation stage. A linear one-way movement was set at a speed of 1 mm/s along the X, Y, and Z directions for a distance of 10 mm each. The coordinates of 3 pre-set target points were recorded at the start and end by a computer binocular vision system with a frequency of 10 FPS and stored in TXT format. The TXT files were imported to Imageware 13.0, and the straight-line lengths between the start and end were measured. The mean difference between each length and 10 mm were calculated to evaluate the correctness of the distance measurement. The linear movement and recording procedure was repeated 3 times, but the speed was changed to 5 mm/s to simulate the human mandibular movement speed. The trajectories of the 3 target points were fitted and the vertical dimensions from each track point to the fitted lines were measured. The mean difference was calculated between the vertical dimensions and 0 mm to evaluate the correctness of recording trajectories using this device. Results: The correctness of distance measurements of the points 1, 2, and 3 were 0.06 mm, 0.16 mm, and 0.08 mm, respectively. The correctness of the trajectories of the points 1, 2, and 3 were 0.11 mm, 0.11 mm, and 0.10 mm, respectively. Conclusion: Using this computer binocular vision device, the correctness of the recorded linear trajectories in the range of 10 mm was better than 0.20 mm.

  14. Gyrineum natator: A potential indicator of imposex along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    Vishwakiran, Y.; Anil, A.C.; Venkat, K.; Sawant, S.S.

    in a seawater recirculating system until further analysis. The animals were cleaned of external fouling and narcotized using 7% MgCl 2 in distilled water. The shell length was measured using Vernier cal- iper from the tip of the protoconch (apex...) to the base of the siphonal canal. Later the shells were crushed using a bench vice to remove the soft body, and the animals were observed through a binocular microscope. Sex was determined by the presence of a capsule gland in fe- males and a prostate...

  15. Phosphatised limestones and associated sediments from the western continental shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.; Natarajan, R.; Parthiban, G.; Mascarenhas, A.

    offshore. As far as vertical variations are observed under a binocular microscope. The P205 concerned, the concentrations down to 25 m are content of the powdered sediment samples was not uniform but below this depth there is a gradual analysed as above... sections were examined using a petrological micro- Stations 15, 27, 35 and 775: The rock types from scope. Powdered samples were analysed for miner- these stations range from rounded through ovoid als and scanned for 10 ° to 40 ° 20 at 2 ° 20/min on a...

  16. 数码相机定位方法的数学模型研究

    Institute of Scientific and Technical Information of China (English)

    苏金林

    2012-01-01

    Through the analysis of the digital camera positioning principle, this paper transform the binary photo to the 0-1 matrix and get image coordinate, and then set up two kinds of models, monocular and binocular model.%通过分析数码相机的定位原理,将相片二值化为0-1矩阵,在此基础上对像做分析,求出其像坐标;并且建立了两种模型,单目模型和双目模型.

  17. Research on the three-dimensional measurement system based on the laser speckle projection

    Science.gov (United States)

    Liang, Lei; Zhao, Weiming; Yue, Tingrui; Duan, Pixuan

    2014-01-01

    This paper studies a three-dimensional non-contact attitude and deformation measuring system of the wind tunnel model. By projecting the single laser speckle on the measured three-dimensional space, it receives a random optical encoding. In addition, correlation search matching for collected image is conducted by matlab, the measurement data results of the existing PIV equipment are compared, and the spin binocular measurement system is employed to obtain the three-dimensional coordinate of the model. As a result, the feasibility of the system is verified. the author grasped the principle of 3D non-contact coding and recognition.

  18. Estudio composicional por difracción de rayos X de pigments del Alero Cárdenas, Provincia de Santa Cruz

    OpenAIRE

    Gradin, Carlos J.; Barbosa, Carlos E.

    1987-01-01

    En total se analizaron 132 muestras cuya posición estratigráfica y composición se detalla en la Tabla 1. Para su análisis las muestras fueron molidas, dispersadas en agua sobre portaobjetos, secadas por reflexión y analizadas mineralógicamente por difracción de rayos X según la metodología descripta por Barbosa y Rial (1984). Con la finalidad de establecer relaciones texturales indicativas de probables orígenes, en algunos casos se realizaron también observaciones con lupe binocular.

  19. Using Stereoscopic 3D Technologies for the Diagnosis and Treatment of Amblyopia in Children

    CERN Document Server

    Gargantini, Angelo

    2011-01-01

    The 3D4Amb project aims at developing a system based on the stereoscopic 3D techonlogy, like the NVIDIA 3D Vision, for the diagnosis and treatment of amblyopia in young children. It exploits the active shutter technology to provide binocular vision, i.e. to show different images to the amblyotic (or lazy) and the normal eye. It would allow easy diagnosis of amblyopia and its treatment by means of interactive games or other entertainment activities. It should not suffer from the compliance problems of the classical treatment, it is suitable to domestic use, and it could at least partially substitute occlusion or patching of the normal eye.

  20. Book review: Birds of Wyoming

    Science.gov (United States)

    Carr, N.B.

    2011-01-01

    "Wyoming may very well be one of the least birded states in the U.S." So begins this book, underscoring the challenges in summarizing existing knowledge for a state that falls next to last in human population density. Despite the relative dearth of "binoculars on the ground," especially in more remote areas of the state, the book offers a thorough compilation of relevant details. Much of this information is not readily accessible from other sources, and this book dispenses essential information in a very usable format.