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. 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.

  5. 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...

  6. 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.

  7. 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

  8. 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...

  9. 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...

  10. The large binocular telescope.

    Science.gov (United States)

    Hill, John M

    2010-06-01

    The Large Binocular Telescope (LBT) Observatory is a collaboration among institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio, and Virginia. The telescope on Mount Graham in Southeastern Arizona uses two 8.4 m diameter primary mirrors mounted side by side. A unique feature of the LBT is that the light from the two Gregorian telescope sides can be combined to produce phased-array imaging of an extended field. This cophased imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65 m aperture and a collecting area equivalent to an 11.8 m circular aperture. This paper describes the design, construction, and commissioning of this unique telescope. We report some sample astronomical results with the prime focus cameras. We comment on some of the technical challenges and solutions. The telescope uses two F/15 adaptive secondaries to correct atmospheric turbulence. The first of these adaptive mirrors has completed final system testing in Firenze, Italy, and is planned to be at the telescope by Spring 2010.

  11. The large binocular telescope.

    Science.gov (United States)

    Hill, John M

    2010-06-01

    The Large Binocular Telescope (LBT) Observatory is a collaboration among institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio, and Virginia. The telescope on Mount Graham in Southeastern Arizona uses two 8.4 m diameter primary mirrors mounted side by side. A unique feature of the LBT is that the light from the two Gregorian telescope sides can be combined to produce phased-array imaging of an extended field. This cophased imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65 m aperture and a collecting area equivalent to an 11.8 m circular aperture. This paper describes the design, construction, and commissioning of this unique telescope. We report some sample astronomical results with the prime focus cameras. We comment on some of the technical challenges and solutions. The telescope uses two F/15 adaptive secondaries to correct atmospheric turbulence. The first of these adaptive mirrors has completed final system testing in Firenze, Italy, and is planned to be at the telescope by Spring 2010. PMID:20517352

  12. 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...

  13. 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...

  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. Assessing the binocular advantage in aided vision.

    Science.gov (United States)

    Harrington, Lawrence K; McIntire, John P; Hopper, Darrel G

    2014-09-01

    Advances in microsensors, microprocessors, and microdisplays are creating new opportunities for improving vision in degraded environments through the use of head-mounted displays. Initially, the cutting-edge technology used in these new displays will be expensive. Inevitably, the cost of providing the additional sensor and processing required to support binocularity brings the value of binocularity into question. Several assessments comparing binocular, binocular, and monocular head-mounted displays for aided vision have concluded that the additional performance, if any, provided by binocular head-mounted displays does not justify the cost. The selection of a biocular [corrected] display for use in the F-35 is a current example of this recurring decision process. It is possible that the human binocularity advantage does not carry over to the aided vision application, but more likely the experimental approaches used in the past have been too coarse to measure its subtle but important benefits. Evaluating the value of binocularity in aided vision applications requires an understanding of the characteristics of both human vision and head-mounted displays. With this understanding, the value of binocularity in aided vision can be estimated and experimental evidence can be collected to confirm or reject the presumed binocular advantage, enabling improved decisions in aided vision system design. This paper describes four computational approaches-geometry of stereopsis, modulation transfer function area for stereopsis, probability summation, and binocular summation-that may be useful in quantifying the advantage of binocularity in aided vision.

  16. 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

  17. 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...

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. High level binocular rivalry effects

    Directory of Open Access Journals (Sweden)

    Michal eWolf

    2011-12-01

    Full Text Available Binocular rivalry (BR occurs when the brain cannot fuse percepts from the two eyes because they are different. We review results relating to an ongoing controversy regarding the cortical site of the BR mechanism. Some BR qualities suggest it is low-level: 1 BR, as its name implies, is usually between eyes and only low levels have access to utrocular information. 2 All input to one eye is suppressed: blurring doesn’t stimulate accommodation; pupilary constrictions are reduced; probe detection is reduced. 3 Rivalry is affected by low level attributes, contrast, spatial frequency, brightness, motion. 4 There is limited priming due to suppressed words or pictures. On the other hand, recent studies favor a high level mechanism: 1 Rivalry occurs between patterns, not eyes, as in patchwork rivalry or a swapping paradigm. 2 Attention affects alternations. 3 Context affects dominance. There is conflicting evidence from physiological studies (single cell and fMRI regarding cortical level(s of conscious perception. We discuss the possibility of multiple BR sites and theoretical considerations that rule out this solution.We present new data regarding the locus of the BR switch by manipulating stimulus semantic content or high-level characteristics. Since these variations are represented at higher cortical levels, their affecting rivalry supports high-level BR intervention. In Experiment I, we measure rivalry when one eye views words and the other nonwords and find significantly longer dominance durations for nonwords. In Experiment II, we find longer dominance times for line drawings of simple, structurally impossible figures than for similar, possible objects. In Experiment III, we test the influence of idiomatic context on rivalry between words. Results show that generally words within their idiomatic context have longer mean dominance durations. We conclude that Binocular Rivalry has high-level cortical influences, and may be controlled by a high

  4. 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.

  5. 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

  6. 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...

  7. 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...

  8. 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.

  9. 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.

  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. 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.

  12. 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....

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Binocular coordination in response to stereoscopic stimuli

    Science.gov (United States)

    Liversedge, Simon P.; Holliman, Nicolas S.; Blythe, Hazel I.

    2009-02-01

    Humans actively explore their visual environment by moving their eyes. Precise coordination of the eyes during visual scanning underlies the experience of a unified perceptual representation and is important for the perception of depth. We report data from three psychological experiments investigating human binocular coordination during visual processing of stereoscopic stimuli.In the first experiment participants were required to read sentences that contained a stereoscopically presented target word. Half of the word was presented exclusively to one eye and half exclusively to the other eye. Eye movements were recorded and showed that saccadic targeting was uninfluenced by the stereoscopic presentation, strongly suggesting that complementary retinal stimuli are perceived as a single, unified input prior to saccade initiation. In a second eye movement experiment we presented words stereoscopically to measure Panum's Fusional Area for linguistic stimuli. In the final experiment we compared binocular coordination during saccades between simple dot stimuli under 2D, stereoscopic 3D and real 3D viewing conditions. Results showed that depth appropriate vergence movements were made during saccades and fixations to real 3D stimuli, but only during fixations on stereoscopic 3D stimuli. 2D stimuli did not induce depth vergence movements. Together, these experiments indicate that stereoscopic visual stimuli are fused when they fall within Panum's Fusional Area, and that saccade metrics are computed on the basis of a unified percept. Also, there is sensitivity to non-foveal retinal disparity in real 3D stimuli, but not in stereoscopic 3D stimuli, and the system responsible for binocular coordination responds to this during saccades as well as fixations.

  19. 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…

  20. The Binocular Advantage in Visuomotor Tasks Involving Tools

    Directory of Open Access Journals (Sweden)

    Jenny C. A. Read

    2013-04-01

    Full Text Available We compared performance on three manual-dexterity tasks under monocular and binocular viewing. The tasks were the standard Morrisby Fine Dexterity Test, using forceps to manipulate the items, a modified version of the Morrisby test using fingers, and a “buzz-wire” task in which subjects had to guide a wire hoop around a 3D track without bringing the hoop into contact with the track. In all three tasks, performance was better for binocular viewing. The extent of the binocular advantage in individuals did not correlate significantly with their stereoacuity measured on the Randot test. However, the extent of the binocular advantage depended strongly on the task. It was weak when fingers were used on the Morrisby task, stronger with forceps, and extremely strong on the buzz-wire task (fivefold increase in error rate with monocular viewing. We suggest that the 3D buzz-wire game is particularly suitable for assessing binocularly based dexterity.

  1. The binocular advantage in visuomotor tasks involving tools.

    Science.gov (United States)

    Read, Jenny C A; Begum, Shah Farzana; McDonald, Alice; Trowbridge, Jack

    2013-01-01

    We compared performance on three manual-dexterity tasks under monocular and binocular viewing. The tasks were the standard Morrisby Fine Dexterity Test, using forceps to manipulate the items, a modified version of the Morrisby test using fingers, and a "buzz-wire" task in which subjects had to guide a wire hoop around a 3D track without bringing the hoop into contact with the track. In all three tasks, performance was better for binocular viewing. The extent of the binocular advantage in individuals did not correlate significantly with their stereoacuity measured on the Randot test. However, the extent of the binocular advantage depended strongly on the task. It was weak when fingers were used on the Morrisby task, stronger with forceps, and extremely strong on the buzz-wire task (fivefold increase in error rate with monocular viewing). We suggest that the 3D buzz-wire game is particularly suitable for assessing binocularly based dexterity.

  2. Fisiologia da visão binocular Physiology of binocular vision

    Directory of Open Access Journals (Sweden)

    Harley E. A. Bicas

    2004-02-01

    Full Text Available A visão binocular de seres humanos resulta da superposição quase completa dos campos visuais de cada olho, o que suscita discriminação perceptual de localizações espaciais de objetos relativamente ao observador (localização egocêntrica bem mais fina (estereopsia, mas isso ocorre em, apenas, uma faixa muito estreita (o horóptero. Aquém e além dela, acham-se presentes diplopia e confusão, sendo necessária supressão fisiológica (cortical para evitá-las. Analisa-se a geometria do horóptero e suas implicações fisiológicas (o desvio de Hillebrand, a partição de Kundt, a área de Panum, assim como aspectos clínicos da visão binocular normal (percepção simultânea, fusão, visão estereoscópica e de adaptações a seus estados afetados (supressão patológica, ambliopia, correspondência visual anômala.The binocular vision of human beings is given by the almost complete superimposition of the monocular visual fields, which allows a finer perceptual discrimination of the egocentric localization of objects in space (stereopsis but only within a very narrow band (the horopter. Before and beyond it, diplopia and confusion are present, so that a physiologic (cortical suppression is necessary to avoid them to become conscious. The geometry of the horopter and its physiologic implications (Hillebrand's deviation, Kundt's partition, Panum's area, stereoscopic vision are analyzed, as well as some clinical aspects of the normal binocular vision (simultaneous perception, fusion, stereoscopic vision and of adaptations to abnormal states (pathologic suppression, amblyopia, abnormal retinal correspondence.

  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. 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...

  6. 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.

  7. 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...

  8. 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 ...

  9. 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...

  10. 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 ...

  11. 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.

  12. The performance of the blue prime focus Large Binocular Camera at the Large Binocular Telescope

    CERN Document Server

    Giallongo, E; Grazian, A; Baruffolo, A; Beccari, G; De Santis, C; Diolaiti, E; Di Paola, A; Farinato, J; Fontana, A; Gallozzi, S; Gasparo, F; Gentile, G; Green, R; Hill, J; Kuhn, O; Pasian, F; Pedichini, F; Radovich, M; Salinari, P; Smareglia, R; Speziali, R; Testa, V; Thompson, D; Vernet, E; Wagner, R M

    2008-01-01

    We present the characteristics and some early scientific results of the first instrument at the Large Binocular Telescope (LBT), the Large Binocular Camera (LBC). Each LBT telescope unit will be equipped with similar prime focus cameras. The blue channel is optimized for imaging in the UV-B bands, the red channel is optimized for imaging in the VRIz bands. The corrected field of view for each camera is about 30 arcmin of diameter and the chip area is equivalent to a 23x23 arcmin2 field. In this paper we also present the commissioning results of the blue channel. Several measurements have been obtained to assess the technical and scientific performance of the blue camera. Among others, astrometric distortion, flat fielding, ghosts and photometric calibration. These measurements have been used as input to a data reduction pipeline applied to the science data selected for the commissioning of the instrument. The measurements obtained during the commissioning showed that the technical performance of the Blue came...

  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. Range-balancing the Large Binocular Telescope

    Science.gov (United States)

    Rakich, A.; Thompson, D.; Kuhn, O. P.

    2011-10-01

    The Large Binocular Telescope (LBT) consists of two 8.4 m telescopes mounted on a common alt-az gimbal. The telescope has various modes of operation, including prime-focus, bent- and direct-Gregorian modes. The telescopes can feed independent instruments or their light can be combined in one of two interferometric instruments, giving an interferometric baseline of over 22 m. With all large telescopes, including the LBT, collimation models or modeled values for hexapod positions, are required to maintain reasonable optical alignment over the working range of temperatures and telescope elevations. Unlike other telescopes, the LBT has a highly asymmetric mechanical structure, and as a result the collimation models are required to do a lot more "work", than on an equivalent aperture monocular telescope that are usually designed to incorporate a Serurrier truss arrangement. LBT has been phasing in science operations over the last 5 years, with first light on the prime-focus cameras in 2006, and first light in Gregorian mode in 2008. In this time the generation of collimation models for LBT has proven to be problematic, with large departures from a given model, and large changes in pointing, being the norm. A refined approach to generating collimation models, "range balancing", has greatly improved this situation. The range-balancing approach to generating collimation models has delivered reliable collimation and pointing in both prime focus and Gregorian modes which has led to greatly increased operational efficiency. The details of the range-balancing approach, involving the removal of pointing "contamination" from collimation data, are given in this paper.

  15. '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

  16. ‘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

  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. Acute alcohol drinking promotes piecemeal percepts during binocular rivalry

    Directory of Open Access Journals (Sweden)

    Dingcai eCao

    2016-04-01

    Full Text Available 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 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.

  19. 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

  20. Multi-coloured stereograms unveil two binocular colour mechanisms in human vision.

    Science.gov (United States)

    Erkelens, Casper J; van Ee, Raymond

    2002-04-01

    Two different colours, one presented to one eye and the other presented to the other eye, often create the impression of a third colour. This percept is known as binocular colour mixture. Here we use coloured stereograms to study binocular colour appearance. Vivid pastel colours are induced in monocular, achromatic patches, if these are placed in stereograms whose left and right images differ in colour. The build-up of the colours is slow and takes tens of seconds or even minutes in certain individuals. The induced colours remain visible during monocular viewing of the patch and decay gradually. The same colours are induced irrespective of whether the patches are placed in fusible or rivalrous stereograms. We show that these colour effects cannot be induced by monocular colour mechanisms, either alone or in combination with binocular colour mixing. We suggest that the colours are induced by a binocular feedback mechanism, which reduces colour differences between the colour appearances of two monocular images. Induced colours are not observed if the achromatic patches are binocular. However, induced colours are apparent if one switches to monocular viewing after prolonged binocular viewing of the binocular patches. This aftereffect suggests that binocular colour induction acts on the monocular representations of binocular images. We suggest that during binocular viewing the fast process of binocular colour mixing masks the changes in colour appearance produced by the much slower process of binocular colour induction.

  1. 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.

  2. Design of Vertically Aligned Binocular Omnistereo Vision Sensor

    Directory of Open Access Journals (Sweden)

    Wang Qing

    2010-01-01

    Full Text Available Abstract Catadioptric omnidirectional vision sensor (ODVS with a fixed single view point is a fast and reliable single panoramic visual information acquisition equipment. This paper presents a new type of binocular stereo ODVS which composes of two ODVS with the same parameters. The single view point of each ODVS is fixed on the same axis with face-to-face, back-to-back, and faceto- back configuration; the single view point design is implemented by catadioptric technology such as the hyperboloid, constant angular resolution, and constant vertical resolution. The catadioptric mirror design uses the method of increasing the resolution of the view field and the scope of the image in the vertical direction. The binocular stereo ODVS arranged in vertical is designed spherical, cylindrical surfaces and rectangular plane coordinate system for 3D calculations. Using the collinearity of two view points, the binocular stereo ODVS is able to easily align the azimuth, while the camera calibration, feature points match, and other cumbersome steps have been simplified. The experiment results show that the proposed design of binocular stereo ODVS can solve the epipolar constraint problems effectively, match three-dimensional image feature points rapidly, and reduce the complexity of three-dimensional measurement considerably.

  3. 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

  4. 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...

  5. 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…

  6. Stability of binocular depth perception with moving head and eyes

    NARCIS (Netherlands)

    Ee, R. van; Erkelens, Casper J.

    2001-01-01

    We systematically analyse the binocular disparity field under various eye, head and stimulus positions and orientations. From the literature we know that certain classes of disparity which involve the entire disparity field (such as those caused by horizontal lateral shift, differential rotation, ho

  7. Visual comfort of binocular and 3D displays

    NARCIS (Netherlands)

    Kooi, F.L.; Toet, A.

    2004-01-01

    Imperfections in binocular image pairs can cause serious viewing discomfort. For example, in stereo vision systems eye strain is caused by unintentional mismatches between the left and right eye images (stereo imperfections). Head-mounted displays can induce eye strain due to optical misalignments.

  8. 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.

  9. 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

  10. 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.

  11. Binocular rivalry alternations and their relation to visual adaptation

    Directory of Open Access Journals (Sweden)

    Daphne eRoumani

    2012-03-01

    Full Text Available 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 adaptation are dispersed throughout the visual system and have an equally influential, or even causal, role in determining perception. Such an explanation of binocular rivalry is also in accordance with the relationship between the latter and attention. However, an overall explanation of this intriguing perceptual phenomenon needs to also include noise as an equally fundamental process involved in the stochastic resonance of perceptual bistability.

  12. 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...

  13. How Does Binocular Disparity Affect the Impressions in Viewing Stereograms?

    Directory of Open Access Journals (Sweden)

    Makoto Ichikawa

    2012-10-01

    Full Text Available We examined how the size of binocular disparity affects the impressions in different dimensions, as well as apparent depth, in viewing line-contoured stereograms, random dot stereogram, and stereoscopic pictures of naturalistic scenes. We used a semantic differential method with the scales that are related to the different dimensions of impression; evaluation, activity, and potency. The stereograms of naturalistic scenes were selected to give observers strong or weak impressions in different impression dimensions. We prepared the two-depth-layer condition and six-depth-layer condition for those stereograms. The size of binocular disparity between the nearest and farthest layers ranged from 0 to about 70 min of arc. Apparent depth magnitude increased with the increment of disparity size for those stereograms while the increment for the six depth-layer condition was larger than that for the two depth-layer conditions. Regardless of the type of stereograms, for the six depth-layer condition, the rating for the evaluation increased with the size of disparity although, for the two-depth-layer condition, it did not increase at the large disparity size. In addition, the rating for the activity increased with disparity size for both the two depth-layer condition and six depth-layer conditions if the stereogram induced some active impression by itself. These results indicate that the effects of binocular disparity size on apparent depth magnitude and impressions in viewing stereoscopic pictures depend upon the depth structure that is specified by binocular disparity, rather than what the stereogram representationally depicts.

  14. 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.

  15. Isolation of Binocular Cues for Motion in Depth

    Directory of Open Access Journals (Sweden)

    Satoshi Shioiri

    2011-05-01

    Full Text Available There are two binocular cues of motion in depth: the interocular velocity difference (IOVD and changing disparity over time (CDOT. Psychophysical evidence for the contribution to perceiving motion in depth has been accumulated for both of the two cues, using techniques to isolate each cue. However, no study estimated seriously how reliably each cue is isolated in the techniques. In this study, we apply a model of motion in depth to estimate how each type of stimuli isolates each of IOVD and CDOT cues. The model consists of the motion energy and the disparity energy detectors as subunits and adds their outputs to built the IOVD and CDOT detectors. Simulations show that some, but not all of stimuli used in the literature are appropriate for isolating cues. The temporally uncorrelated randomdot stereogram isolates CDOT cue and the binocularly uncorrelated randomdot kinematogram isolates IOVD cues. However, temporally anticorreated version of randomdot stereogram has influence of reverse motion components of IOVD and binocularly anticorreated version of randomdot kinematogram has influence of reverse motion components of CDOT. Gratings with opposite orientation between the eyes are also good for isolation of IOVD. We performed psychophysical experiments to examine the plausibility of the model prediction.

  16. Stimulus motion propels traveling waves in binocular rivalry.

    Directory of Open Access Journals (Sweden)

    Tomas Knapen

    Full Text Available State transitions in the nervous system often take shape as traveling waves, whereby one neural state is replaced by another across space in a wave-like manner. In visual perception, transitions between the two mutually exclusive percepts that alternate when the two eyes view conflicting stimuli (binocular rivalry may also take shape as traveling waves. The properties of these waves point to a neural substrate of binocular rivalry alternations that have the hallmark signs of lower cortical areas. In a series of experiments, we show a potent interaction between traveling waves in binocular rivalry and stimulus motion. The course of the traveling wave is biased in the motion direction of the suppressed stimulus that gains dominance by means of the wave-like transition. Thus, stimulus motion may propel the traveling wave across the stimulus to the extent that the stimulus motion dictates the traveling wave's direction completely. Using a computational model, we show that a speed-dependent asymmetry in lateral inhibitory connections between retinotopically organized and motion-sensitive neurons can explain our results. We argue that such a change in suppressive connections may play a vital role in the resolution of dynamic occlusion situations.

  17. 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...

  18. The spatial origin of a perceptual transition in binocular rivalry.

    Directory of Open Access Journals (Sweden)

    Chris L E Paffen

    Full Text Available When the left and the right eye are simultaneously presented with incompatible images at overlapping retinal locations, an observer typically reports perceiving only one of the two images at a time. This phenomenon is called binocular rivalry. Perception during binocular rivalry is not stable; one of the images is perceptually dominant for a certain duration (typically in the order of a few seconds after which perception switches towards the other image. This alternation between perceptual dominance and suppression will continue for as long the images are presented. A characteristic of binocular rivalry is that a perceptual transition from one image to the other generally occurs in a gradual manner: the image that was temporarily suppressed will regain perceptual dominance at isolated locations within the perceived image, after which its visibility spreads throughout the whole image. These gradual transitions from perceptual suppression to perceptual dominance have been labeled as traveling waves of perceptual dominance. In this study we investigate whether stimulus parameters affect the location at which a traveling wave starts. We varied the contrast, spatial frequency or motion speed in one of the rivaling images, while keeping the same parameter constant in the other image. We used a flash-suppression paradigm to force one of the rival images into perceptual suppression. Observers waited until the suppressed image became perceptually dominant again, and indicated the position at which this breakthrough from suppression occurred. Our results show that the starting point of a traveling wave during binocular rivalry is highly dependent on local stimulus parameters. More specifically, a traveling wave most likely started at the location where the contrast of the suppressed image was higher than that of the dominant one, the spatial frequency of the suppressed image was lower than that of the dominant one, and the motion speed of the suppressed

  19. Recovery of cortical binocularity and orientation selectivity after the critical period for ocular dominance plasticity.

    Science.gov (United States)

    Liao, David S; Krahe, Thomas E; Prusky, Glen T; Medina, Alexandre E; Ramoa, Ary S

    2004-10-01

    Cortical binocularity is abolished by monocular deprivation (MD) during a critical period of development lasting from approximately postnatal day (P) 35 to P70 in ferrets. Although this is one of the best-characterized models of neural plasticity and amblyopia, very few studies have examined the requirements for recovery of cortical binocularity and orientation selectivity of deprived eye responses. Recent studies indicating that different mechanisms regulate loss and recovery of binocularity raise the possibility that different sensitive periods characterize loss and recovery of deprived eye responses. In this report, we have examined whether the potential for recovery of binocularity and orientation selectivity is restricted to the critical period. Quantitative single unit recordings revealed recovery of cortical binocularity and full recovery of orientation selectivity of deprived eye responses following prolonged periods of MD (i.e., >3 wk) starting at P49, near the peak of plasticity. Surprisingly, recovery was present when binocular vision was restored after the end of the critical period for ocular dominance plasticity, as late as P83. In contrast, ferrets that had never received visual experience through the deprived eye failed to recover binocularity even though normal binocular vision was restored at P50, halfway through the critical period. Collectively, these results indicate that there is potential for recovery of cortical binocularity and deprived eye orientation selectivity after the end of the critical period for ocular dominance plasticity.

  20. Recent developments for the Large Binocular Telescope Guiding Control Subsystem

    Science.gov (United States)

    Golota, T.; De La Peña, M. D.; Biddick, C.; Lesser, M.; Leibold, T.; Miller, D.; Meeks, R.; Hahn, T.; Storm, J.; Sargent, T.; Summers, D.; Hill, J.; Kraus, J.; Hooper, S.; Fisher, D.

    2014-07-01

    The Large Binocular Telescope (LBT) has eight Acquisition, Guiding, and wavefront Sensing Units (AGw units). They provide guiding and wavefront sensing capability at eight different locations at both direct and bent Gregorian focal stations. Recent additions of focal stations for PEPSI and MODS instruments doubled the number of focal stations in use including respective motion, camera controller server computers, and software infrastructure communicating with Guiding Control Subsystem (GCS). This paper describes the improvements made to the LBT GCS and explains how these changes have led to better maintainability and contributed to increased reliability. This paper also discusses the current GCS status and reviews potential upgrades to further improve its performance.

  1. 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!

  2. 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

  3. 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

  4. Two eyes, one vision: binocular motion perception in human visual cortex

    NARCIS (Netherlands)

    Barendregt, M.

    2016-01-01

    An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

  5. The Large Binocular Telescope as an early ELT

    Science.gov (United States)

    Hill, John; Hinz, Philip; Ashby, David

    2013-12-01

    The Large Binocular Telescope (LBT) has two 8.4-m primary mirrors on a common AZ-EL mounting. The dual Gregorian optical configuration for LBT includes a pair of adaptive secondaries. The adaptive secondaries are working reliably for science observations as well as for the commissioning of new instruments. Many aspects of the LBT telescope design have been optimized for the combination of the two optical trains. The telescope structure is relatively compact and stiff with a lowest eigenfrequency near 8 Hz. A vibration measurement system of accelerometers (OVMS) has been installed to characterize the vibrations of the telescope. A first-generation of the binocular telescope control system has been deployed on-sky. Two instruments, LBTI and LINC-NIRVANA, have been built to take advantage of the 22.65-m diffraction baseline when the telescope is phased. This diffraction-limited imaging capability (beyond 20-m baseline) positions LBT as a forerunner of the new generation of extremely large telescopes (ELT). We discuss here some of the experiences ofphasing the two sides of the telescope starting in 2010. We also report some lessons learned during on-sky commissioning of the LBTI instrument.

  6. 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.

  7. 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

  8. Bilateral symmetry in vision and influence of ocular surgical procedures on binocular vision: A topical review.

    Science.gov (United States)

    Arba Mosquera, Samuel; Verma, Shwetabh

    2016-01-01

    We analyze the role of bilateral symmetry in enhancing binocular visual ability in human eyes, and further explore how efficiently bilateral symmetry is preserved in different ocular surgical procedures. The inclusion criterion for this review was strict relevance to the clinical questions under research. Enantiomorphism has been reported in lower order aberrations, higher order aberrations and cone directionality. When contrast differs in the two eyes, binocular acuity is better than monocular acuity of the eye that receives higher contrast. Anisometropia has an uncommon occurrence in large populations. Anisometropia seen in infancy and childhood is transitory and of little consequence for the visual acuity. Binocular summation of contrast signals declines with age, independent of inter-ocular differences. The symmetric associations between the right and left eye could be explained by the symmetry in pupil offset and visual axis which is always nasal in both eyes. Binocular summation mitigates poor visual performance under low luminance conditions and strong inter-ocular disparity detrimentally affects binocular summation. Considerable symmetry of response exists in fellow eyes of patients undergoing myopic PRK and LASIK, however the method to determine whether or not symmetry is maintained consist of comparing individual terms in a variety of ad hoc ways both before and after the refractive surgery, ignoring the fact that retinal image quality for any individual is based on the sum of all terms. The analysis of bilateral symmetry should be related to the patients' binocular vision status. The role of aberrations in monocular and binocular vision needs further investigation.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Effects of cortical damage on binocular depth perception.

    Science.gov (United States)

    Bridge, Holly

    2016-06-19

    Stereoscopic depth perception requires considerable neural computation, including the initial correspondence of the two retinal images, comparison across the local regions of the visual field and integration with other cues to depth. The most common cause for loss of stereoscopic vision is amblyopia, in which one eye has failed to form an adequate input to the visual cortex, usually due to strabismus (deviating eye) or anisometropia. However, the significant cortical processing required to produce the percept of depth means that, even when the retinal input is intact from both eyes, brain damage or dysfunction can interfere with stereoscopic vision. In this review, I examine the evidence for impairment of binocular vision and depth perception that can result from insults to the brain, including both discrete damage, temporal lobectomy and more systemic diseases such as posterior cortical atrophy.This article is part of the themed issue 'Vision in our three-dimensional world'. PMID:27269597

  15. 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

  16. 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.

  17. 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.

  18. Differential processing of binocular and monocular gloss cues in human visual cortex

    Science.gov (United States)

    Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W.

    2016-01-01

    The visual impression of an object's surface reflectance (“gloss”) relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. PMID:26912596

  19. 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 ...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. 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 ...

  4. 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...

  5. 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...

  6. 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 ...

  7. 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 ...

  8. 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 ...

  9. 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...

  10. 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

  11. M pathway and areas 44 and 45 are involved in stereoscopic recognition based on binocular disparity.

    Science.gov (United States)

    Negawa, Tsuneo; Mizuno, Shinji; Hahashi, Tomoya; Kuwata, Hiromi; Tomida, Mihoko; Hoshi, Hiroaki; Era, Seiichi; Kuwata, Kazuo

    2002-04-01

    We characterized the visual pathways involved in the stereoscopic recognition of the random dot stereogram based on the binocular disparity employing a functional magnetic resonance imaging (fMRI). The V2, V3, V4, V5, intraparietal sulcus (IPS) and the superior temporal sulcus (STS) were significantly activated during the binocular stereopsis, but the inferotemporal gyrus (ITG) was not activated. Thus a human M pathway may be part of a network involved in the stereoscopic processing based on the binocular disparity. It is intriguing that areas 44 (Broca's area) and 45 in the left hemisphere were also active during the binocular stereopsis. However, it was reported that these regions were inactive during the monocular stereopsis. To separate the specific responses directly caused by the stereoscopic recognition process from the nonspecific ones caused by the memory load or the intention, we designed a novel frequency labeled tasks (FLT) sequence. The functional MRI using the FLT indicated that the activation of areas 44 and 45 is correlated with the stereoscopic recognition based on the binocular disparity but not with the intention artifacts, suggesting that areas 44 and 45 play an essential role in the binocular disparity.

  12. An overview of instrumentation for the Large Binocular Telescope

    Science.gov (United States)

    Wagner, R. Mark

    2012-09-01

    An overview of instrumentation for the Large Binocular Telescope (LBT) is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27' x 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 left and right direct F/15 Gregorian foci incorporating multiple slit masks for multi-object spectroscopy over a 6' field and spectral resolutions of up to 2000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCI), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at the left and right front bent F/15 Gregorian foci and designed for seeing-limited (FOV: 4' × 4') imaging, long-slit spectroscopy, and multiobject spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0'.5 × 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development that can utilize the full 23-m baseline of the LBT 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). LBTI is currently undergoing commissioning on the LBT and utilizing the installed adaptive secondary mirrors in both single- sided and two-sided beam combination modes. 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. Over the past four years the LBC pair, LUCI1, and MODS1 have been commissioned and are now scheduled for routine partner science observations. The delivery of both LUCI2 and MODS2 is anticipated before the end of 2012. The

  13. 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.

  14. Early laser operations at the Large Binocular Telescope Observatory

    Science.gov (United States)

    Rahmer, Gustavo; Lefebvre, Michael; Christou, Julian; Raab, Walfried; Rabien, Sebastian; Ziegleder, Julian; Borelli, José L.; Gässler, Wolfgang

    2014-08-01

    ARGOS is the GLAO (Ground-Layer Adaptive Optics) Rayleigh-based LGS (Laser Guide Star) facility for the Large Binocular Telescope Observatory (LBTO). It is dedicated for observations with LUCI1 and LUCI2, LBTO's pair of NIR imagers and multi-object spectrographs. The system projects three laser beams from the back of each of the two secondary mirror units, which create two constellations circumscribed on circles of 2 arcmin radius with 120 degree spacing. Each of the six Nd:YAG lasers provides a beam of green (532nm) pulses at a rate of 10kHz with a power of 14W to 18W. We achieved first on-sky propagation on the night of November 5, 2013, and commissioning of the full system will take place during 2014. We present the initial results of laser operations at the observatory, including safety procedures and the required coordination with external agencies (FAA, Space Command, and Military Airspace Manager). We also describe our operational procedures and report on our experiences with aircraft spotters. Future plans for safer and more efficient aircraft monitoring and detection are discussed.

  15. 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.

  16. Misperception of aspect ratio in binocularly viewed surfaces.

    Science.gov (United States)

    Hibbard, Paul B; Goutcher, Ross; O'Kane, Lisa M; Scarfe, Peter

    2012-10-01

    The horizontal-vertical illusion, in which the vertical dimension is overestimated relative to the horizontal direction, has been explained in terms of the statistical relationship between the lengths of lines in the world, and the lengths of their projections onto the retina (Howe & Purves, 2002). The current study shows that this illusion affects the apparent aspect ratio of shapes, and investigates how it interacts with binocular cues to surface slant. One way in which statistical information could give rise to the horizontal-vertical illusion would be through prior assumptions about the distribution of slant. This prior would then be expected to interact with retinal cues to slant. We determined the aspect ratio of stereoscopically viewed ellipses that appeared circular. We show that observers' judgements of aspect ratio were affected by surface slant, but that the largest image vertical:horizontal aspect ratio that was considered to be a surface with a circular profile was always found for surfaces close to fronto-parallel. This is not consistent with a Bayesian model in which the horizontal-vertical illusion arises from a non-uniform prior probability distribution for slant. Rather, we suggest that assumptions about the slant of surfaces affect apparent aspect ratio in a manner that is more heuristic, and partially dissociated from apparent slant. PMID:22925917

  17. When crowding meets binocular rivalry: challenges for object perception.

    Science.gov (United States)

    Kim, Sangrae; Shin, Eunsam; Chong, Sang Chul

    2013-01-14

    Both crowding and binocular rivalry impair object perception, but their influence on object perception has so far only been investigated in separate fields. Three experiments investigated the joint influences of crowding and rivalry on object perception (orientation discrimination). Experiment 1 investigated how crowding and rivalry influence orientation discrimination together. Experiment 2 tested whether rivalry between flankers affects crowding using an orientation discrimination task. Experiment 3 tested whether crowding affects the temporal dynamics of the rivalry between a target and a rival stimulus. In Experiment 1, judgments of target orientation were more impaired when crowding and rivalry were simultaneously induced than when they were separately induced and their effects were combined. In Experiment 2, judgments of target orientation were impaired even when flankers were undergoing rivalry, thus highlighting the importance of the presence of flankers. Experiment 3 showed that flankers presented in the neighborhood of a target undergoing rivalry shortened target dominance and prolonged target suppression. The augmented impairments of object perception found in Experiments 1 and 3 suggest that crowding and rivalry interact, presumably through signal suppression. The adverse effect of flankers shown in Experiment 2 suggests that inappropriate feature integration may have additionally contributed to this interaction.

  18. Binocular rivalry waves in a directionally selective neural field model

    Science.gov (United States)

    Carroll, Samuel R.; Bressloff, Paul C.

    2014-10-01

    We extend a neural field model of binocular rivalry waves in the visual cortex to incorporate direction selectivity of moving stimuli. For each eye, we consider a one-dimensional network of neurons that respond maximally to a fixed orientation and speed of a grating stimulus. Recurrent connections within each one-dimensional network are taken to be excitatory and asymmetric, where the asymmetry captures the direction and speed of the moving stimuli. Connections between the two networks are taken to be inhibitory (cross-inhibition). As per previous studies, we incorporate slow adaption as a symmetry breaking mechanism that allows waves to propagate. We derive an analytical expression for traveling wave solutions of the neural field equations, as well as an implicit equation for the wave speed as a function of neurophysiological parameters, and analyze their stability. Most importantly, we show that propagation of traveling waves is faster in the direction of stimulus motion than against it, which is in agreement with previous experimental and computational studies.

  19. 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...

  20. Temporal Integration of Auditory Stimulation and Binocular Disparity Signals

    Directory of Open Access Journals (Sweden)

    Marina Zannoli

    2011-10-01

    Full Text Available Several studies using visual objects defined by luminance have reported that the auditory event must be presented 30 to 40 ms after the visual stimulus to perceive audiovisual synchrony. In the present study, we used visual objects defined only by their binocular disparity. We measured the optimal latency between visual and auditory stimuli for the perception of synchrony using a method introduced by Moutoussis & Zeki (1997. Visual stimuli were defined either by luminance and disparity or by disparity only. They moved either back and forth between 6 and 12 arcmin or from left to right at a constant disparity of 9 arcmin. This visual modulation was presented together with an amplitude-modulated 500 Hz tone. Both modulations were sinusoidal (frequency: 0.7 Hz. We found no difference between 2D and 3D motion for luminance stimuli: a 40 ms auditory lag was necessary for perceived synchrony. Surprisingly, even though stereopsis is often thought to be slow, we found a similar optimal latency in the disparity 3D motion condition (55 ms. However, when participants had to judge simultaneity for disparity 2D motion stimuli, it led to larger latencies (170 ms, suggesting that stereo motion detectors are poorly suited to track 2D motion.

  1. The Large Binocular Telescope azimuth and elevation encoder system

    Science.gov (United States)

    Ashby, David S.; Sargent, Tom; Cox, Dan; Rosato, Jerry; Brynnel, Joar G.

    2008-08-01

    A typical high-resolution encoder interpolator relies on careful mechanical alignment of the encoder read-heads and tight electrical tolerances of the signal processing electronics to ensure linearity. As the interpolation factor increases, maintaining these tight mechanical and electrical tolerances becomes impractical. The Large Binocular Telescope (LBT) is designed to utilize strip-type encoders on the main axes. Because of the very large scale of the telescope, the accumulative length of the azimuth and elevation encoder strips exceeds 80 meters, making optical tape prohibitively expensive. Consequently, the designers of the LBT incorporated the far less expensive Farrand Controls Inductosyn® linear strip encoder to encode the positions of the main axes and the instrument rotators. Since the cycle pitch of these encoders is very large compared to that of optical strip encoders, the interpolation factor must also be large in order to achieve the 0.005 arcsecond encoder resolution as specified. The authors present a description of the innovative DSP-based hardware / software solution that adaptively characterizes and removes common systematic cycle-to-cycle encoder interpolation errors. These errors can be caused by mechanical misalignment, encoder manufacturing flaws, variations in electrical gain, signal offset or cross-coupling of the encoder signals. Simulation data are presented to illustrate the performance of the interpolation algorithm, and telemetry data are presented to demonstrate the actual performance of the LBT main-axis encoder system.

  2. [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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Binocular coordination of saccades during reading in children with clinically assessed poor vergence capabilities.

    Science.gov (United States)

    Gaertner, Chrystal; Bucci, Maria Pia; Ajrezo, Layla; Wiener-Vacher, Sylvette

    2013-07-19

    Prior studies have pointed toward a link between the saccadic and vergence systems, coordinating binocular saccadic movements. Recent studies have shown that vergence deficits in children induce poor binocular coordination during saccades, but none of them have studied ocular motility in children during a daily task such as reading. The present study tests whether vergence deficits in children perturb binocular coordination of saccades and fixation during reading. Our second objective was to explore whether vergence training could improve the quality of binocular coordination. Twelve patients (from 7.3 to 13.4 years old) complaining from vertigo but without vestibular and neurological pathology underwent orthoptic tests and were selected for our study when they presented vergence deficits. Eye movements were recorded during a reading task with a Mobile EyeBrain® Tracker video-oculography system. Data were compared to twelve age-matched controls with normal orthoptic values. While there was no statistically significant difference in saccade amplitudes between the two groups (p=0.29), patients showed higher disconjugacy during and after the saccades compared to controls (p<0.001). After orthoptic training, six patients out of the first 12 examined came back for a second oculomotor test. All showed a significant improvement of their binocular saccade coordination. We suggest that the larger disconjugacy during reading observed in patients before training could be due to poor vergence as initially assessed by orthoptic examination. Such findings support the hypothesis of a tight relationship between the saccadic and vergence systems for controlling the binocular coordination of saccades. The improvement reported after orthoptic training is in line with the hypothesis of an adaptative interaction on a premotor level between the saccadic and vergence system.

  8. 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.

  9. 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

  10. 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.

  11. 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).

  12. 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…

  13. 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...

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. 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)

  3. Monocular and binocular development in children with albinism, infantile nystagmus syndrome and normal vision

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (nn=n16), children with infantile nystagmus syndrome (nn=n10), and children with normal vision (nn=n72). Methods: Interocular acuity differences and

  4. Monocular and binocular development in children with albinism, infantile nystagmus syndrome, and normal vision

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Abstract Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (n = 16), children with infantile nystagmus syndrome (n = 10), and children with normal vision (n = 72). Methods: Interocular acuity differe

  5. Quality assessment of stereoscopic 3D image compression by binocular integration behaviors.

    Science.gov (United States)

    Lin, Yu-Hsun; Wu, Ja-Ling

    2014-04-01

    The objective approaches of 3D image quality assessment play a key role for the development of compression standards and various 3D multimedia applications. The quality assessment of 3D images faces more new challenges, such as asymmetric stereo compression, depth perception, and virtual view synthesis, than its 2D counterparts. In addition, the widely used 2D image quality metrics (e.g., PSNR and SSIM) cannot be directly applied to deal with these newly introduced challenges. This statement can be verified by the low correlation between the computed objective measures and the subjectively measured mean opinion scores (MOSs), when 3D images are the tested targets. In order to meet these newly introduced challenges, in this paper, besides traditional 2D image metrics, the binocular integration behaviors-the binocular combination and the binocular frequency integration, are utilized as the bases for measuring the quality of stereoscopic 3D images. The effectiveness of the proposed metrics is verified by conducting subjective evaluations on publicly available stereoscopic image databases. Experimental results show that significant consistency could be reached between the measured MOS and the proposed metrics, in which the correlation coefficient between them can go up to 0.88. Furthermore, we found that the proposed metrics can also address the quality assessment of the synthesized color-plus-depth 3D images well. Therefore, it is our belief that the binocular integration behaviors are important factors in the development of objective quality assessment for 3D images.

  6. Gaze-grasp coordination in obstacle avoidance: differences between binocular and monocular viewing.

    Science.gov (United States)

    Grant, Simon

    2015-12-01

    Most adults can skillfully avoid potential obstacles when acting in everyday cluttered scenes. We examined how gaze and hand movements are normally coordinated for obstacle avoidance and whether these are altered when binocular depth information is unavailable. Visual fixations and hand movement kinematics were simultaneously recorded, while 13 right-handed subjects reached-to-precision grasp a cylindrical household object presented alone or with a potential obstacle (wine glass) located to its left (thumb's grasp side), right or just behind it (both closer to the finger's grasp side) using binocular or monocular vision. Gaze and hand movement strategies differed significantly by view and obstacle location. With binocular vision, initial fixations were near the target's centre of mass (COM) around the time of hand movement onset, but usually shifted to end just above the thumb's grasp site at initial object contact, this mainly being made by the thumb, consistent with selecting this digit for guiding the grasp. This strategy was associated with faster binocular hand movements and improved end-point grip precision across all trials than with monocular viewing, during which subjects usually continued to fixate the target closer to its COM despite a similar prevalence of thumb-first contacts. While subjects looked directly at the obstacle at each location on a minority of trials and their overall fixations on the target were somewhat biased towards the grasp side nearest to it, these gaze behaviours were particularly marked on monocular vision-obstacle behind trials which also commonly ended in finger-first contact. Subjects avoided colliding with the wine glass under both views when on the right (finger side) of the workspace by producing slower and straighter reaches, with this and the behind obstacle location also resulting in 'safer' (i.e. narrower) peak grip apertures and longer deceleration times than when the goal object was alone or the obstacle was on its

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. First Results From the Large Binocular Telescope: Deep Photometry of New dSphs

    CERN Document Server

    Coleman, Matthew G

    2007-01-01

    This contribution describes photometry for two Galactic dSphs obtained with the Large Binocular Telescope to a magnitude of ~25.5. Using the Large Binocular Camera, a purpose-built wide-field imager for the LBT, we have examined the structure and star formation histories of two newly-discovered Local Group members, the Hercules dSph and the Leo T dSph/dIrr system. We have constructed a structural map for the Hercules system using three-filter photometry to V ~ 25.5. This is the first deep photometry for this system, and it indicates that Hercules is unusually elongated, possibly indicating distortion due to the Galactic tidal field. We have also derived the first star formation history for the Leo T system, and find that its oldest population of stars (age ~ 13 Gyr) were relatively metal-rich, with [Fe/H] ~ -1.5.

  13. 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.

  14. The Role of Binocular Disparity in Rapid Scene and Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Matteo Valsecchi

    2013-04-01

    Full Text Available 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 showed that observers were in principle able to extract spatial patterns defined only by disparity under brief, masked presentations. Comparing our results with the predictions from a cue-summation model, we showed that combining disparity with luminance did not per se disrupt the processing of disparity. Our results suggest that the rapid recognition of scenes is mediated mostly by a monocular comparison of the images, although we can rely on stereo in fast pattern recognition.

  15. 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.

  16. 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 .

  17. 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.

  18. 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...

  19. 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 ...

  20. 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...

  1. 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 \

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

    Science.gov (United States)

    Chopin, Adrien; Mamassian, Pascal; Blake, Randolph

    2012-06-15

    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 those transitions by means of a superimposed tilt illusion. Fusion was attested by a correct stereoscopic slant perception of the grid. The superimposed tilt illusion was achieved in displaying small segments on the grids. We found that the illusion can change the fusion-rivalry transitions indicating that rivalry and fusion are based on the perceived orientations rather than the displayed ones. In a second experiment, we confirmed that the absence of binocular rivalry resulted in fusion and stereoscopic slant perception. We conclude that the superimposed tilt illusion arises at a level of visual processing prior to those stages mediating binocular rivalry and stereoscopic depth extraction.

  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. Characterization of Visual Symptomatology Associated with Refractive, Accommodative, and Binocular Anomalies

    Directory of Open Access Journals (Sweden)

    Pilar Cacho-Martínez

    2015-01-01

    Full Text Available Purpose. To characterize the symptomatology of refractive, accommodative, and nonstrabismic binocular dysfunctions and to assess the association between dysfunctions and symptoms. Methods. 175 randomised university students were examined. Subjects were given a subjective visual examination with accommodative and binocular tests, evaluating their symptomatology. Accommodative and binocular dysfunctions (AD, BD were diagnosed according to the number of existing clinical signs: suspect AD or BD (one fundamental clinical sign, high suspect (one fundamental + 1 complementary clinical sign, and definite (one fundamental + 2 or more complementary clinical signs. A logistic regression was conducted in order to determine whether there was an association between dysfunctions and symptoms. Results. 78 subjects (44.6% reported any kind of symptoms which were grouped into 18 categories, with “visual fatigue” being the most frequent (20% of the overall complaints. Logistic regression adjusted by the presence of an uncorrected refractive error showed no association between any grade of AD and symptoms. Subjects with BD had more likelihood of having symptoms than without dysfunction group (OR = 3.35, being greater when only definite BD were considered (OR = 8.79. Conclusions. An uncorrected refractive error is a confusion factor when considering AD symptomatology. For BD, the more the number of clinical signs used the greater the likelihood suffering symptoms.

  5. 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

  6. Clinical Outcomes after Binocular Implantation of a New Trifocal Diffractive Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Florian T. A. Kretz

    2015-01-01

    Full Text Available Purpose. To evaluate visual, refractive, and contrast sensitivity outcomes, as well as the incidence of pseudophakic photic phenomena and patient satisfaction after bilateral diffractive trifocal intraocular lens (IOL implantation. Methods. This prospective nonrandomized study included consecutive patients undergoing cataract surgery with bilateral implantation of a diffractive trifocal IOL (AT LISA tri 839MP, Carl Zeiss Meditec. Distance, intermediate, and near visual outcomes were evaluated as well as the defocus curve and the refractive outcomes 3 months after surgery. Photopic and mesopic contrast sensitivity, patient satisfaction, and halo perception were also evaluated. Results. Seventy-six eyes of 38 patients were included; 90% of eyes showed a spherical equivalent within ±0.50 diopters 3 months after surgery. All patients had a binocular uncorrected distance visual acuity of 0.00 LogMAR or better and a binocular uncorrected intermediate visual acuity of 0.10 LogMAR or better, 3 months after surgery. Furthermore, 85% of patients achieved a binocular uncorrected near visual acuity of 0.10 LogMAR or better. Conclusions. Trifocal diffractive IOL implantation seems to provide an effective restoration of visual function for far, intermediate, and near distances, providing high levels of visual quality and patient satisfaction.

  7. 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

  8. 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 [40 yrs (IQR: 32-42 yrs and 25 age-matched controls [30 yrs (25-37 yrs]. 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%; 620.8 arc sec (370.3-988.2 arc sec] than in controls [79% (63.5-100%; 16.3 arc sec (10.6-25.5 arc sec] (p<0.001. Higher-order wavefront aberrations of the transplanted eye [0.34 μ (0.21-0.51 μ] were higher than the fellow eye [0.07 μ (0.05-0.11 μ] (p<0.001 and their reduction with RGP contact lenses [0.09 μ (0.08-0.12 μ] significantly improved the suppression threshold [65% (50-72%] and stereoacuity [56.6 arc sec (47.7-181.6 arc 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

  9. 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

  10. Binocular Glaucomatous Visual Field Loss and Its Impact on Visual Exploration - A Supermarket Study

    Science.gov (United States)

    Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

    2014-01-01

    Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i) assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii) to identify factors influencing the performance, and (iii) to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP), and ten healthy-sighted control subjects (GC) were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as “passed” or “failed” with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item). Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s) to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p<0.001). Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD) area than patients who failed (t-test, p<0.05). According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a “time-effective” compensatory mechanism during the present supermarket task. PMID:25162522

  11. Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study.

    Science.gov (United States)

    Sippel, Katrin; Kasneci, Enkelejda; Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

    2014-01-01

    Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i) assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii) to identify factors influencing the performance, and (iii) to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP), and ten healthy-sighted control subjects (GC) were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item). Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s) to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p < 0.001). Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD) area than patients who failed (t-test, p < 0.05). According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

  12. Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study.

    Directory of Open Access Journals (Sweden)

    Katrin Sippel

    Full Text Available Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii to identify factors influencing the performance, and (iii to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP, and ten healthy-sighted control subjects (GC were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item. Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p < 0.001. Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD area than patients who failed (t-test, p < 0.05. According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

  13. 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

  14. A neural network approach to fMRI binocular visual rivalry task analysis.

    Directory of Open Access Journals (Sweden)

    Nicola Bertolino

    Full Text Available The purpose of this study was to investigate whether artificial neural networks (ANN are able to decode participants' conscious experience perception from brain activity alone, using complex and ecological stimuli. To reach the aim we conducted pattern recognition data analysis on fMRI data acquired during the execution of a binocular visual rivalry paradigm (BR. Twelve healthy participants were submitted to fMRI during the execution of a binocular non-rivalry (BNR and a BR paradigm in which two classes of stimuli (faces and houses were presented. During the binocular rivalry paradigm, behavioral responses related to the switching between consciously perceived stimuli were also collected. First, we used the BNR paradigm as a functional localizer to identify the brain areas involved the processing of the stimuli. Second, we trained the ANN on the BNR fMRI data restricted to these regions of interest. Third, we applied the trained ANN to the BR data as a 'brain reading' tool to discriminate the pattern of neural activity between the two stimuli. Fourth, we verified the consistency of the ANN outputs with the collected behavioral indicators of which stimulus was consciously perceived by the participants. Our main results showed that the trained ANN was able to generalize across the two different tasks (i.e. BNR and BR and to identify with high accuracy the cognitive state of the participants (i.e. which stimulus was consciously perceived during the BR condition. The behavioral response, employed as control parameter, was compared with the network output and a statistically significant percentage of correspondences (p-value <0.05 were obtained for all subjects. In conclusion the present study provides a method based on multivariate pattern analysis to investigate the neural basis of visual consciousness during the BR phenomenon when behavioral indicators lack or are inconsistent, like in disorders of consciousness or sedated patients.

  15. 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.

  16. 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.

  17. 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...

  18. On-site calibration method for outdoor binocular stereo vision sensors

    Science.gov (United States)

    Liu, Zhen; Yin, Yang; Wu, Qun; Li, Xiaojing; Zhang, Guangjun

    2016-11-01

    Using existing calibration methods for binocular stereo vision sensors (BSVS), it is very difficult to extract target characteristic points in outdoor environments under complex light conditions. To solve the problem, an online calibration method for BSVS based a double parallel cylindrical target and a line laser projector is proposed in this paper. The intrinsic parameters of two cameras are calibrated offline. Laser strips on the double parallel cylindrical target are mediated to calibrate the configuration parameters of BSVS. The proposed method only requires images of laser strips on the target and is suitable for the calibration of BSVS in outdoor environments. The effectiveness of the proposed method is validated through physical experiments.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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.

  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. 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.

  7. How Simultaneous is the Perception of Binocular Depth and Rivalry in Plaid Stimuli?

    Directory of Open Access Journals (Sweden)

    Athena Buckthought

    2012-06-01

    Full Text Available Psychophysical experiments have demonstrated that it is possible to perceive both binocular depth and rivalry in plaids (Buckthought and Wilson 2007, Vision Research 47 2543–2556. In a recent study, we investigated the neural substrates for depth and rivalry processing with these plaid patterns, when either a depth or rivalry task was performed (Buckthought and Mendola 2011, Journal of Vision 11 1–15. However, the extent to which perception of the two stimulus aspects was truly simultaneous remained somewhat unclear. In the present study, we introduced a new task in which subjects were instructed to perform both depth and rivalry tasks concurrently. Subjects were clearly able to perform both tasks at the same time, but with a modest, symmetric drop in performance when compared to either task carried out alone. Subjects were also able to raise performance levels for either task by performing it with a higher priority, with a decline in performance for the other task. The symmetric declines in performance are consistent with the interpretation that the two tasks are equally demanding of attention (Braun and Julesz 1998, Perception & Psychophysics 60 1–23. The results demonstrate the impressive combination of binocular features that supports coincident depth and rivalry in surface perception, within the constraints of presumed orientation and spatial frequency channels.

  8. 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...

  9. An Active Stereo Vision System Based on Neural Pathways of Human Binocular Motor System

    Institute of Scientific and Technical Information of China (English)

    Yu-zhang Gu; Makoto Sato; Xiao-lin Zhang

    2007-01-01

    An active stereo vision system based on a model of neural pathways of human binocular motor system is proposed. With this model, it is guaranteed that the two cameras of the active stereo vision system can keep their lines of sight fixed on the same target object during smooth pursuit. This feature is very important for active stereo vision systems, since not only 3D reconstruction needs the two cameras have an overlapping field of vision, but also it can facilitate the 3D reconstruction algorithm. To evaluate the effectiveness of the proposed method, some software simulations are done to demonstrate the same target tracking characteristic in a virtual environment apt to mistracking easily. Here, mistracking means two eyes track two different objects separately. Then the proposed method is implemented in our active stereo vision system to perform real tracking task in a laboratory scene where several persons walk self-determining. Before the proposed model is implemented in the system, mistracking occurred frequently. After it is enabled, mistracking never occurred. The result shows that the vision system based on neural pathways of human binocular motor system can reliably avoid mistracking.

  10. 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...

  11. A near-ultraviolet view of the Inner Region of M31 with the Large Binocular Telescope

    CERN Document Server

    Beccari, G; Clementini, G; Federici, L; Pecci, F Fusi; Galleti, S; Montegriffo, P; Giallongo, E; Ragazzoni, R; Grazian, A; Baruffolo, A; De Santis, C; Diolaiti, E; Di Paola, A; Farinato, J; Fontana, A; Gallozzi, S; Gasparo, F; Gentile, G; Green, R; Hill, J; Kuhn, O; Menci, N; Pedichini, F Pasian F; Smareglia, R; Speziali, R; Testa, V; Thompson, D; Vernet, E; Wagner, R M

    2007-01-01

    We present a 900 sec, wide-field U image of the inner region of the Andromeda galaxy obtained during the commissioning of the blue channel of the Large Binocular Camera mounted on the prime focus of the Large Binocular Telescope. Relative photometry and absolute astrometry of individual sources in the image was obtained along with morphological parameters aimed at discriminating between stars and extended sources, e.g. globular clusters. The image unveils the near-ultraviolet view of the inner ring of star formation recently discovered in the infrared by the Spitzer Space Telescope and shows in great detail the fine structure of the dust lanes associated with the galaxy inner spiral arms. The capabilities of the blue channel of the Large Binocular Camera at the Large Binocular Telescope (LBC-Blue) are probed by direct comparison with ultraviolet GALEX observations of the same region in M31. We discovered 6 new candidate stellar clusters in this high-background region of M31. We also recovered 62 bona-fide glo...

  12. 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....

  13. Binocular Saccade Coordination in Reading and Visual Search: A Developmental Study in Typical Reader and Dyslexic Children

    Directory of Open Access Journals (Sweden)

    Magali eSeassau

    2014-10-01

    Full Text Available Studies dealing with developmental aspects of binocular eye movement behavior during reading are scarce. In this study we have explored binocular strategies during reading and visual search tasks in a large population of dyslexic and typical readers. Binocular eye movements were recorded using a video-oculography system in 43 dyslexic children (aged 8 to 13 and in a group of 42 age-matched typical readers. The main findings are (i ocular motor characteristics of dyslexic children are impaired in comparison to those reported in typical children in reading task ; (ii a developmental effect exists in reading in control children; in dyslexic children the effect of development was observed only on fixation durations ; (iii ocular motor behavior in the visual search tasks is similar for dyslexic children and for typical readers, except for the disconjugacy during and after the saccade: dyslexic children are impaired in comparison to typical children. Data reported here confirms and expands previous studies on children’s reading. Both reading skills and binocular saccades coordination improve with age in typical readers. The atypical eye movement’s patterns observed in dyslexic children suggest a deficiency in the visual attentional processing as well as an impairment of the ocular motor saccade and vergence systems interaction.

  14. An overview and the current status of instrumentation at the Large Binocular Telescope Observatory

    Science.gov (United States)

    Wagner, R. Mark; Edwards, Michelle L.; Kuhn, Olga; Thompson, David; Veillet, Christian

    2014-07-01

    An overview of instrumentation for the Large Binocular Telescope (LBT) is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (24' × 24') 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 left and right direct F/15 Gregorian foci incorporating multiple slit masks for multi-object spectroscopy over a 6' field and spectral resolutions of up to 2000. Infrared instrumentation includes the LBT Near-IR Spectrometer (LUCI), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at the left and right front-bent F/15 Gregorian foci 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 x 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development that can utilize the full 23 m baseline of the LBT 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). LBTI is currently undergoing commissioning and performing science observations on the LBT utilizing the installed adaptive secondary mirrors in both single-sided and two-sided beam combination modes. 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. Installation and testing of the bench spectrograph will begin in July 2014. Over the past four years the LBC pair, LUCI1, and MODS1 have been commissioned and are now scheduled for routine partner science observations. Both LUCI2 and MODS2 passed their laboratory

  15. 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

  16. 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

  17. The Search for Failed Supernovae with the Large Binocular Telescope: Constraints from 7 Years of Data

    CERN Document Server

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

    2016-01-01

    We report updated results for the first 7 years of our program to monitor 27 galaxies within 10 Mpc using the Large Binocular Telescope to search for failed supernovae -- core-collapses of massive stars that form black holes without luminous supernovae. In the new data, we identify no new compelling candidates and confirm the existing candidate. Given the 6 successful core-collapse SNe in the sample and one likely failed SN, the implied fraction of core-collapses that result in failed SNe is $f = 0.14^{+0.33}_{-0.10}$ at 90% confidence. If the current candidate is a failed SN, the fraction of failed SN naturally explains the missing high-mass RSG SN progenitors and the black hole mass function. If the current candidate is ultimately rejected, the data implies a 90% confidence upper limit on the failed SN fraction of $f < 0.35$.

  18. 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.

  19. 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...... multivariate classification on MEG data recorded when participants reported changes in conscious perception evoked by binocular rivalry between a face and a grating, we showed that only MEG signals in the 120–320 msec time range, peaking at the M170 around 180 msec and the P2m at around 260 msec, reliably...... predicted conscious experience. Conscious perception could not only be decoded significantly better than chance from the sensors that showed the largest average difference, as previous studies suggest, but also from patterns of activity across groups of occipital sensors that individually were unable...

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Validation of the Vertical Heterophoria Symptom Questionnaire (VHS-Q) In Patients with Balance Problems and Binocular Visual Dysfunction after Acquired Brain Injury

    DEFF Research Database (Denmark)

    Schow, Trine; Teasdale, Thomas William; Arendt Rasmussen, Morten

    2016-01-01

    Trine Schow, Thomas William Teasdale and Morten Arendt Rasmussen Validation of the Vertical Heterophoria Symptom Questionnaire (VHS-Q) In Patients with Balance Problems and Binocular Visual Dysfunction after Acquired Brain Injury. SOJ Psychology (in Press)......Trine Schow, Thomas William Teasdale and Morten Arendt Rasmussen Validation of the Vertical Heterophoria Symptom Questionnaire (VHS-Q) In Patients with Balance Problems and Binocular Visual Dysfunction after Acquired Brain Injury. SOJ Psychology (in Press)...

  5. 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 ...

  6. Precision calibration method for binocular vision measurement systems based on arbitrary translations and 3D-connection information

    Science.gov (United States)

    Yang, Jinghao; Jia, Zhenyuan; Liu, Wei; Fan, Chaonan; Xu, Pengtao; Wang, Fuji; Liu, Yang

    2016-10-01

    Binocular vision systems play an important role in computer vision, and high-precision system calibration is a necessary and indispensable process. In this paper, an improved calibration method for binocular stereo vision measurement systems based on arbitrary translations and 3D-connection information is proposed. First, a new method for calibrating the intrinsic parameters of binocular vision system based on two translations with an arbitrary angle difference is presented, which reduces the effect of the deviation of the motion actuator on calibration accuracy. This method is simpler and more accurate than existing active-vision calibration methods and can provide a better initial value for the determination of extrinsic parameters. Second, a 3D-connection calibration and optimization method is developed that links the information of the calibration target in different positions, further improving the accuracy of the system calibration. Calibration experiments show that the calibration error can be reduced to 0.09%, outperforming traditional methods for the experiments of this study.

  7. Large binocular telescope interferometer adaptive optics: on-sky performance and lessons learned

    Science.gov (United States)

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

    2014-07-01

    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 103 - 104 contrast at 10 μm, while the 4 μm imaging science drivers require even greater contrasts, but at scales <0.2". In imaging mode, LBTI's Adaptive Optics system is already delivering 4 μm contrast of 104 - 105 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 μm, with future plans to test at shorter wavelengths and with more modes. We find evidence of NCPA variability on short timescales and discuss possible upgrades to ameliorate time-variable effects.

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

    Science.gov (United States)

    Defrère, D.; Hinz, P. M.; 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.

    2016-06-01

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5–13 μm). In this paper, we focus on the mid-infrared (8–13 μm) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, 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 exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star β Leo. This is equivalent to an exozodiacal disk density of 15–30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  10. 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)...

  11. 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=...

  12. 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.

  13. 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...

  14. 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.

  15. 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.

  16. iLocater: A Diffraction-limited Doppler Spectrometer for the Large Binocular Telescope

    CERN Document Server

    Crepp, Justin R; King, David; Bechter, Andrew; Bechter, Eric; Ketterer, Ryan; Reynolds, Robert; Hinz, Philip; Kopon, Derek; Cavalieri, David; Fantano, Louis; Koca, Corina; Onuma, Eleanya; Stapelfeldt, Karl; Thomes, Joseph; Wall, Sheila; Macenka, Steven; McGuire, James; Korniski, Ronald; Zugby, Leonard; Eisner, Joshua; Gaudi, B Scott; Hearty, Fred; Kratter, Kaitlin; Kuchner, Marc; Micela, Giusi; Nelson, Matthew; Pagano, Isabella; Quirrenbach, Andreas; Schwab, Christian; Skrutskie, Michael; Sozzetti, Alessandro; Woodward, Charles E; Zhao, Bo

    2016-01-01

    We are developing a stable and precise spectrograph for the Large Binocular Telescope (LBT) named "iLocater." The instrument comprises three principal components: a cross-dispersed echelle spectrograph that operates in the YJ-bands (0.97-1.30 microns), a fiber-injection acquisition camera system, and a wavelength calibration unit. iLocater will deliver high spectral resolution (R~150,000-240,000) measurements that permit novel studies of stellar and substellar objects in the solar neighborhood including extrasolar planets. Unlike previous planet-finding instruments, which are seeing-limited, iLocater operates at the diffraction limit and uses single mode fibers to eliminate the effects of modal noise entirely. By receiving starlight from two 8.4m diameter telescopes that each use "extreme" adaptive optics (AO), iLocater shows promise to overcome the limitations that prevent existing instruments from generating sub-meter-per-second radial velocity (RV) precision. Although optimized for the characterization of ...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. High Contrast Imaging in the Visible: First Experimental Results at the Large Binocular Telescope

    CERN Document Server

    Pedichini, F; Ambrosino, A; Puglisi, A; Pinna, E; Bailey, V; Carbonaro, L; Centrone, M; Christou, J; Esposito, S; Farinato, J; Fiore, F; Giallongo, E; Hill, J M; Hinz, P M; Sabatini, L

    2016-01-01

    In February 2014, the SHARK-VIS (System for High contrast And coronography from R to K at VISual bands) Forerunner, a high contrast experimental imager operating at visible wavelengths, was installed at LBT (Large Binocular Telescope). Here we report on the first results obtained by recent on-sky tests. These results show the extremely good performance of the LBT ExAO (Extreme Adaptive Optics) system at visible wavelengths, both in terms of spatial resolution and contrast achieved. Similarly to what was done by (Amara et al. 2012), we used the SHARK-VIS Forerunner data to quantitatively assess the contrast enhancement. This is done by injecting several different synthetic faint objects in the acquired data and applying the ADI (angular differential imaging) technique. A contrast of the order of $5 \\times 10^{-5}$ is obtained at 630 nm for angular separations from the star larger than 100 mas. These results are discussed in light of the future development of SHARK-VIS and compared to those obtained by other hi...

  4. 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.

  5. Binocular robot vision emulating disparity computation in the primary visual cortex.

    Science.gov (United States)

    Shimonomura, Kazuhiro; Kushima, Takayuki; Yagi, Tetsuya

    2008-01-01

    We designed a VLSI binocular vision system that emulates the disparity computation in the primary visual cortex (V1). The system consists of two silicon retinas, orientation chips, and field programmable gate array (FPGA), mimicking a hierarchical architecture of visual information processing in the disparity energy model. The silicon retinas emulate a Laplacian-Gaussian-like receptive field of the vertebrate retina. The orientation chips generate an orientation-selective receptive field by aggregating multiple pixels of the silicon retina, mimicking the Hubel-Wiesel-type feed-forward model in order to emulate a Gabor-like receptive field of simple cells. The FPGA receives outputs from the orientation chips corresponding to the left and right eyes and calculates the responses of the complex cells based on the disparity energy model. The system can provide the responses of complex cells tuned to five different disparities and a disparity map obtained by comparing these energy outputs. Owing to the combination of spatial filtering by analog parallel circuits and pixel-wise computation by hard-wired digital circuits, the present system can execute the disparity computation in real time using compact hardware.

  6. 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.

  7. Maintaining hexapod range while co-pointing the Large Binocular Telescope

    Science.gov (United States)

    Rakich, A.; Thompson, D.; Kuhn, O. P.

    2011-10-01

    The Large Binocular Telescope on Mt Graham in Arizona consists of two 8.4 m telescopes mounted on a common gimbal. Each independent telescope has hexapods controlling the position of individual optical elements. These can be used to drive each telescope to point to a common target (or known offsets to these) as is required for many of the observational modes of the telescope. The hexapods have a limited range of travel, particularly the primary mirror hexapods. This paper discusses the approach that has been taken to achieve optical co-pointing while maintaining the maximum possible range of travel in the hexapods. The approach described here is, starting with collimated but not co-pointed telescopes, to first calculate a coma-free rotation of the optical elements that will equalize the percentage consumption of range on pairs of hexapod elements that affect {X,Y} pointing; i.e. {X, Ry} and {Y, Rx} respectively. On a collimated telescope this results in a state which maximizes the available range of travel of the hexapods for a given set of initial hexapod values. Next a further calculation step is taken which achieves optical co-pointing. This step takes into account what range of travel is available for each hexapod for the given "range-balanced" starting point, then allocates a percentage of the required optical copointing to each telescope so as to maximize the available range of hexapod travel on each side. This technique has been applied successfully to both the prime-focus and "bent-Gregorian" modes of the telescope.

  8. Distribution of Binocular Vision Anomalies and Refractive Errors in Iranian Children With Learning Disabilities

    Directory of Open Access Journals (Sweden)

    Yekta

    2015-11-01

    Full Text Available Background Visual problems in children contribute to learning disorders, which are one of the most influential factors in learning. Objectives The aim of the present study was to determine the prevalence of refractive and binocular vision errors in children with learning disorders. Patients and Methods In this cross-sectional study, 406 children with learning disorders with a mean age of 8.56 ± 2.4 years were evaluated. Examinations included the determination of refractive errors with an auto-refractometer and static retinoscopy, measurement of visual acuity with a Snellen chart, evaluation of ocular deviation, and measurement of stereopsis, amplitude of accommodation, and near point of convergence. Results Of the 406 participants, 319 (78.6% were emmetropic in the right eye, 14.5% had myopia, and 6.9% had hyperopia according to cycloplegic refraction. Astigmatism was detected in 75 (18.5% children. In our study, 89.9% of the children had no deviation, 1.0% had esophoria, and 6.4% had exophoria . In addition, 2.2% of the children had suppression. The near point of convergence ranged from 3 to 18 cm, with a mean of 10.12 ± 3.274 cm. Moreover, 98.5 and 98.0% of the participants achieved complete vision with the best correction in the right and left eye, respectively. The best corrected visual acuity in the right and left eye was achieved in 98.5 and 98.0% of the children, respectively. Conclusions The pattern of visual impairment in learning-impaired children is not much different from that in normal children; however, because these children may not be able to express themselves clearly, lack of correct diagnosis and appropriate treatment has resulted in a marked defect in recognizing visual disorders in these children. Therefore, gaining knowledge of the prevalence of refractive errors in children with learning disorders can be considered the first step in their treatment.

  9. Parabolic flight reveals independent binocular control of otolith-induced eye torsion

    Science.gov (United States)

    Markham, C. H.; Diamond, S. G.; Stoller, D. F.

    2000-01-01

    To examine otolith-governed ocular torsion in hyper- and hypogravity, eight subjects, including two astronauts, underwent parabolic flight while seated upright with head fixed. A mask fitted with two video cameras provided synchronized images of both eyes at a rate of 25/sec during 15 parabolas, the individual parabolas separated by a few minutes of level 1 G flight. Three main findings emerged: 1) After the first parabola, most subjects showed differential torsional offset of the two eyes in the 1 G portions between parabolas, compared to the conjugate baseline position of the eyes prior to the first parabola. 2) Changes in binocular torsion in the 0 G and 1.8 G portions of parabolic flight revealed in most subjects systematic reversal of direction. The reversal was consistent within, but not across subjects. 3) Disconjugacy defined as the moment-to-moment difference in the movements of the two eyes, and evaluated without the contribution of the differential offset, found two subjects with relatively high disconjugacy scores, and the remaining six with low scores. On the basis of prior studies (9, 20), we would predict the first two would be subject to SMS, the remainder not. The two astronauts, who did not have SMS on their space missions, fell into the low scoring group. We propose that the disconjugacies may be due to intrinsic asymmetries in the otolith receptors on the two sides of the head, which appear to be independently linked to the extraocular muscles of the two eyes, a phenomenon masked in normal 1 G states by adaptation. The apparently independent control of the two sides cannot be detected by the simpler and more common monocular studies.

  10. Binocular Coordination of the Human Vestibulo-Ocular Reflex during Off-axis Pitch Rotation

    Science.gov (United States)

    Wood, S. J.; Reschke, M. F.; Kaufman, G. D.; Black, F. O.; Paloski, W. H.

    2006-01-01

    Head movements in the sagittal pitch plane typically involve off-axis rotation requiring both vertical and horizontal vergence ocular reflexes to compensate for angular and translational motion relative to visual targets of interest. The purpose of this study was to compare passive pitch VOR responses during rotation about an Earth-vertical axis (canal only cues) with off-axis rotation (canal and otolith cues). Methods. Eleven human subjects were oscillated sinusoidally at 0.13, 0.3 and 0.56 Hz while lying left-side down with the interaural axis either aligned with the axis of rotation or offset by 50 cm. In a second set of measurements, twelve subjects were also tested during sinusoidally varying centrifugation over the same frequency range. The modulation of vertical and horizontal vergence ocular responses was measured with a binocular videography system. Results. Off-axis pitch rotation enhanced the vertical VOR at lower frequencies and enhanced the vergence VOR at higher frequencies. During sinusoidally varying centrifugation, the opposite trend was observed for vergence, with both vertical and vergence vestibulo-ocular reflexes being suppressed at the highest frequency. Discussion. These differential effects of off-axis rotation over the 0.13 to 0.56 Hz range are consistent with the hypothesis that otolith-ocular reflexes are segregated in part on the basis of stimulus frequency. At the lower frequencies, tilt otolith-ocular responses compensate for declining canal input. At higher frequencies, translational otolith-ocular reflexes compensate for declining visual contributions to the kinematic demands required for fixating near targets.

  11. 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)

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Wide and deep near-UV (360nm) galaxy counts and the extragalactic background light with the Large Binocular Camera

    CERN Document Server

    Grazian, A; Giallongo, E; Gallozzi, S; Fontanot, F; Fontana, A; Testa, V; Ragazzoni, R; Baruffolo, A; Beccari, G; Diolaiti, E; Di Paola, A; Farinato, J; Gasparo, F; Gentile, G; Green, R; Hill, J; Kuhn, O; Pasian, F; Pedichini, F; Radovich, M; Smareglia, R; Speziali, R; Thompson, D; Wagner, R M

    2009-01-01

    Deep multicolour surveys are the main tool to explore the formation and evolution of the faint galaxies which are beyond the spectroscopic limit with the present technology. The photometric properties of these faint galaxies are usually compared with current renditions of semianalytical models to provide constraints on the fundamental physical processes involved in galaxy formation and evolution, namely the mass assembly and the star formation. Galaxy counts over large sky areas in the near-UV band are important because they are difficult to obtain given the low efficiency of near-UV instrumentation, even at 8m class telescopes. A large instrumental field of view helps in minimizing the biases due to the cosmic variance. We have obtained deep images in the 360nm U band provided by the blue channel of the Large Binocular Camera at the prime focus of the Large Binocular Telescope. We have derived over an area of ~0.4 sq. deg. the galaxy number counts down to U=27 in the Vega system (corresponding to U=27.86 in ...

  14. Two-eyed versus one-eyed salamanders: does binocularity enhance the optically evoked skin blanching reactions of Ambystoma larvae?

    Science.gov (United States)

    Pietsch, P; Schneider, C W

    1990-08-01

    A wide variety of visual functions show increases attributable to binocularity, and the question pursued here was whether a second eye enhances the visually stimulated skin blanching reaction of the larval salamander. Dermal melanin spots (produced by the aggregations of melanosomes within dermal melanophores and which contract or expand to lighten or darken the skin) were measured in eyeless (controls), one-eyed and two-eyed Ambystoma punctatum larvae after chronic adaptation of the subjects to a white background (i.e., stimulus conditions for maximum blanching). The eyeless subjects showed no blanching (thus remained dark) in white cups, and they exhibited melanin spots 7 or 8 times the size of those of the other two groups. All one-eyed or two-eyed subjects exhibited blanching reactions; planometric comparison revealed a significantly larger melanin spot area for one-eyed than for two-eyed animals; i.e., the binocular condition permitted greater contraction of the pigment spots than did the monocular condition. Analytical data compared favorably with independently ascertained pigmentation indices. The results indicate that a second eye quantitatively elevates the blanching maximum of a larval salamander.

  15. 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

  16. 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。

  17. 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 .

  18. 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.

  19. Stereo Vision Integration Based on Binocular Views%基于双目感知的立体视觉集成

    Institute of Scientific and Technical Information of China (English)

    杨阳

    2016-01-01

    虽然计算机视觉的应用场景拓宽,关于双目视觉的算法和理论研究达到一定的深度。双目立体视觉感知是通过双目摄像机在接近平行且距离较近的位置上获取同一场景不同角度的图像,进而通过二维图像获取三维信息。基于双目视觉工作原理,提出一种综合的双目感知立体视觉集成框架,其中主要包括图像预处理模块,立体匹配算法模块、点云融合显示模块。在其使用算法方面进行简要介绍,并达到集成处理效果。%As the application of computer vision scene is broad, the theoretical studies algorithms of binocular vision have achieved a certain depth. The binocular stereo vision is to access images in different perspectives on the same scene by binocular cameras at a close range and in parallel, and then obtain 3D information from 2D images. Puts forward a comprehensive binocular stereo vision integration framework based on the binocular visions, which includes image preprocessing module, stereo matching algorithm module, point cloud fusion and display module. Carries out the brief introduction of basic algorithms and achieves the integration.

  20. Incidence of vertical phoria on postural control during binocular vision: what perspective for prevention to nonspecific chronic pain management?

    Science.gov (United States)

    Matheron, Eric; Kapoula, Zoï

    2015-01-01

    Vertical heterophoria (VH) is the latent vertical misalignment of the eyes when the retinal images are dissociated, vertical orthophoria (VO) when there is no misalignment. Studies on postural control, during binocular vision in upright stance, reported that healthy subjects with small VH vs. VO are less stable, but the experimental cancellation of VH with an appropriate prism improves postural stability. The same behavior was recorded in nonspecific chronic back pain subjects, all with VH. It was hypothesized that, without refraction problems, VH indicates a perturbation of the somaesthetic cues required in the sensorimotor loops involved in postural control and the capacity of the CNS to optimally integrate these cues, suggesting prevention possibilities. Sensorimotor conflict can induce pain and modify sensory perception in some healthy subjects; some nonspecific pain or chronic pain could result from such prolonged conflict in which VH could be a sign, with new theoretical and clinical implications.

  1. 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.

  2. Shading Beats Binocular Disparity in Depth from Luminance Gradients: Evidence against a Maximum Likelihood Principle for Cue Combination.

    Directory of Open Access Journals (Sweden)

    Chien-Chung Chen

    Full Text Available Perceived depth is conveyed by multiple cues, including binocular disparity and luminance shading. Depth perception from luminance shading information depends on the perceptual assumption for the incident light, which has been shown to default to a diffuse illumination assumption. We focus on the case of sinusoidally corrugated surfaces to ask how shading and disparity cues combine defined by the joint luminance gradients and intrinsic disparity modulation that would occur in viewing the physical corrugation of a uniform surface under diffuse illumination. Such surfaces were simulated with a sinusoidal luminance modulation (0.26 or 1.8 cy/deg, contrast 20%-80% modulated either in-phase or in opposite phase with a sinusoidal disparity of the same corrugation frequency, with disparity amplitudes ranging from 0'-20'. The observers' task was to adjust the binocular disparity of a comparison random-dot stereogram surface to match the perceived depth of the joint luminance/disparity-modulated corrugation target. Regardless of target spatial frequency, the perceived target depth increased with the luminance contrast and depended on luminance phase but was largely unaffected by the luminance disparity modulation. These results validate the idea that human observers can use the diffuse illumination assumption to perceive depth from luminance gradients alone without making an assumption of light direction. For depth judgments with combined cues, the observers gave much greater weighting to the luminance shading than to the disparity modulation of the targets. The results were not well-fit by a Bayesian cue-combination model weighted in proportion to the variance of the measurements for each cue in isolation. Instead, they suggest that the visual system uses disjunctive mechanisms to process these two types of information rather than combining them according to their likelihood ratios.

  3. 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.

  4. Vertical binocular disparity is encoded implicitly within a model neuronal population tuned to horizontal disparity and orientation.

    Directory of Open Access Journals (Sweden)

    Jenny C A Read

    2010-04-01

    Full Text Available Primary visual cortex is often viewed as a "cyclopean retina", performing the initial encoding of binocular disparities between left and right images. Because the eyes are set apart horizontally in the head, binocular disparities are predominantly horizontal. Yet, especially in the visual periphery, a range of non-zero vertical disparities do occur and can influence perception. It has therefore been assumed that primary visual cortex must contain neurons tuned to a range of vertical disparities. Here, I show that this is not necessarily the case. Many disparity-selective neurons are most sensitive to changes in disparity orthogonal to their preferred orientation. That is, the disparity tuning surfaces, mapping their response to different two-dimensional (2D disparities, are elongated along the cell's preferred orientation. Because of this, even if a neuron's optimal 2D disparity has zero vertical component, the neuron will still respond best to a non-zero vertical disparity when probed with a sub-optimal horizontal disparity. This property can be used to decode 2D disparity, even allowing for realistic levels of neuronal noise. Even if all V1 neurons at a particular retinotopic location are tuned to the expected vertical disparity there (for example, zero at the fovea, the brain could still decode the magnitude and sign of departures from that expected value. This provides an intriguing counter-example to the common wisdom that, in order for a neuronal population to encode a quantity, its members must be tuned to a range of values of that quantity. It demonstrates that populations of disparity-selective neurons encode much richer information than previously appreciated. It suggests a possible strategy for the brain to extract rarely-occurring stimulus values, while concentrating neuronal resources on the most commonly-occurring situations.

  5. Binocular Fusion and Invariant Category Learning due to Predictive Remapping during Scanning of a Depthful Scene with Eye Movements

    Directory of Open Access Journals (Sweden)

    Stephen eGrossberg

    2015-01-01

    Full Text Available How does the brain maintain stable fusion of 3D scenes when the eyes move? Every eye movement causes each retinal position to process a different set of scenic features, and thus the brain needs to binocularly fuse new combinations of features at each position after an eye movement. Despite these breaks in retinotopic fusion due to each movement, previously fused representations of a scene in depth often appear stable. The 3D ARTSCAN neural model proposes how the brain does this by unifying concepts about how multiple cortical areas in the What and Where cortical streams interact to coordinate processes of 3D boundary and surface perception, spatial attention, invariant object category learning, predictive remapping, eye movement control, and learned coordinate transformations. The model explains data from single neuron and psychophysical studies of covert visual attention shifts prior to eye movements. The model further clarifies how perceptual, attentional, and cognitive interactions among multiple brain regions (LGN, V1, V2, V3A, V4, MT, MST, PPC, LIP, ITp, ITa, SC may accomplish predictive remapping as part of the process whereby view-invariant object categories are learned. These results build upon earlier neural models of 3D vision and figure-ground separation and the learning of invariant object categories as the eyes freely scan a scene. A key process concerns how an object’s surface representation generates a form-fitting distribution of spatial attention, or attentional shroud, in parietal cortex that helps maintain the stability of multiple perceptual and cognitive processes. Predictive eye movement signals maintain the stability of the shroud, as well as of binocularly fused perceptual boundaries and surface representations.

  6. 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.

  7. 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

  8. 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...

  9. 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...

  10. 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

  11. 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.

  12. 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.

  13. 基于各向异性竞争的双目滤波器%A Binocular Filter Based on Anisotropic Competition

    Institute of Scientific and Technical Information of China (English)

    彭雄宏; 周宗潭; 王正志

    2001-01-01

    鉴于立体图象对中特征的视差确定是计算机立体视觉研究的一个难点,因此在FACADE初级视觉理论的框架下,针对生物视觉系统对不同方向特征的不对称处理,结合细胞动力学方程实现了一种基于各向异性竞争的双目滤波器.这种改进了的基于各向异性竞争策略FACADE系统,由于更有利于将双目特征匹配还原为细胞活性的自组织活动,因此获得了真实场景中的视差分布%In the field of computer vision,it's difficult to get the disparity of features from stereo images.In this paper,a binocular filter based on anisotropic competition which adapted from FACADE theory to find disparity of features is proposed.Binocular filter use cells activity to represent the disparity distribution of features.There is competition between cells before the disparity distribution of features is acquired.Because of the horizontal bias of “eyes” configuration in binocular vision system,features with different orientation must be processed differently.Anisotropic competition is used in order to consider features with different orientation in a uniform way.The method of anisotropic competition better the performance of FACADE model by favoring the self-organization of cell activities.This approach is much different from the traditional method of matching the elements in the two images,which provides a different view of computer vision research.

  14. Eight-dimensional methodology for innovative thinking about the case and ethics of the Mount Graham, Large Binocular Telescope project.

    Science.gov (United States)

    Berne, Rosalyn W; Raviv, Daniel

    2004-04-01

    This paper introduces the Eight Dimensional Methodology for Innovative Thinking (the Eight Dimensional Methodology), for innovative problem solving, as a unified approach to case analysis that builds on comprehensive problem solving knowledge from industry, business, marketing, math, science, engineering, technology, arts, and daily life. It is designed to stimulate innovation by quickly generating unique "out of the box" unexpected and high quality solutions. It gives new insights and thinking strategies to solve everyday problems faced in the workplace, by helping decision makers to see otherwise obscure alternatives and solutions. Daniel Raviv, the engineer who developed the Eight Dimensional Methodology, and paper co-author, technology ethicist Rosalyn Berne, suggest that this tool can be especially useful in identifying solutions and alternatives for particular problems of engineering, and for the ethical challenges which arise with them. First, the Eight Dimensional Methodology helps to elucidate how what may appear to be a basic engineering problem also has ethical dimensions. In addition, it offers to the engineer a methodology for penetrating and seeing new dimensions of those problems. To demonstrate the effectiveness of the Eight Dimensional Methodology as an analytical tool for thinking about ethical challenges to engineering, the paper presents the case of the construction of the Large Binocular Telescope (LBT) on Mount Graham in Arizona. Analysis of the case offers to decision makers the use of the Eight Dimensional Methodology in considering alternative solutions for how they can proceed in their goals of exploring space. It then follows that same process through the second stage of exploring the ethics of each of those different solutions. The LBT project pools resources from an international partnership of universities and research institutes for the construction and maintenance of a highly sophisticated, powerful new telescope. It will soon mark

  15. How Auditory Information Influences Volitional Control in Binocular Rivalry: Modulation of a Top-Down Attentional Effect

    Directory of Open Access Journals (Sweden)

    Manuel Vidal

    2011-10-01

    / although it could be equivalent to promoting lips uttering /ada/. Our findings suggest that at higher-level processing stages, auditory cues do interact with the perceptual decision and with the dominance mechanism involved during visual rivalry. These results are discussed according to the individual differences in the audio-visual integration for speech perception. We propose a descriptive model based on known characteristics of binocular rivalry, which accounts for most of these findings. In this model, the top-down attentional control (volition is modulated by lower-level audio-visual matching.

  16. 基于双目立体视觉的深度信息测量%Depth Information Measurement Based on Binocular Stereo Vision

    Institute of Scientific and Technical Information of China (English)

    王玉翰; 金波

    2015-01-01

    介绍了双目立体视觉三角测距原理和视觉测量系统,双目摄像机拍摄彩色图像,提取颜色、轮廓、纹理等识别特征用于目标区域识别。采用区域匹配算法获得视差图,根据视差计算目标区域的三维坐标信息。完成了目标测量实验并对实验结果进行分析。%The triangulation ranging principle of binocular stereo vision and vision measurement system were presented, and color images were taked from binocular cameras. Color,contour,texture features were extracted from the image for target area recognition. Obtaining disparity map from color images by region based stereo matching algorithms, three-dimensional coordinate information of target area were calculated according to the disparity map. Target measurement experiment and analyse of the results were completed.

  17. 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...

  18. 远、近视性屈光参差视功能对比研究%Comparative study of myopic and hyperopic anisometropia on binocular vision

    Institute of Scientific and Technical Information of China (English)

    罗俊; 漆争艳; 何容; 王平; 唐璟; 向剑波; 杨俊芳

    2014-01-01

    AIM: To investigate the effect of both myopic and hyperopic anisometropia on binocular vision. METHODS: Totally 238 patients with corrected anisometropia and 30 normal children were tested with both stereogram and synoptophore for their near stereoacuity and binocular vision. The correlation of anisometropia and binocular vision was studied statistically. RESULTS:The number of normal near stereoacuity and distance fusion range of myopic anisometropia was significantly higher than that of hyperopic anisometropia. A few of hyperopic anisometropia had normal stereopsis. Most of low anisometropia group had sub -normal stereopsis, while high, severe anisometropia group without stereopsis.Most of myopic anisometropia group had normal stereopsis or sub-normal stereopsis. CONCLUSION:The hyperopic anisometropia produces a more profound effect. Relationship between anisometropia and stereopsis are analyzed according to nature.%目的:对比分析远、近视性屈光参差对患者双眼视功能的影响。  方法:对238例屈光矫正后的屈光参差者和30例正常者进行近立体视和同视机三级视功能检查,并记录其结果。  结果:近视性屈光参差远、近立体视及融合功能正常者的例数高于远视性屈光参差者。远视性屈光参差组有正常立体视者少,低度屈光参差组以亚正常立体视者为主,而高、重度屈光参差组多无立体视;近视性屈光参差组多有正常立体视或亚正常立体视。  结论:近视性屈光参差的双眼视功能总体优于远视性屈光参差,但屈光参差与立体视的关系应按性质分别进行分析。

  19. 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

  20. Design of Augmented Reality Evaluation System Based on Binocular Vision%基于双目视觉的增强现实模型系统设计

    Institute of Scientific and Technical Information of China (English)

    陈春妃; 陈琼; 汤勇明

    2016-01-01

    To improve monocular vision shortcoming of unrealistic,uncomfortable and small range users,an augment⁃ed reality evaluation system is proposed,which selects high resolution,wide color gamut and high integration 2 mm× 17 mm micro OLED display as an imaging image source,large size BS prism and a concave mirror as an imaging ele⁃ment,control the image magnification to improve the field of view. The system can achieve high clarity and stability of monocular and binocular augmented reality imaging effect. With a multi-dimensional adjustable degree,the magni⁃fication times can be from one to infinite,the eyes’district and binocular image synthesis angle also can be adjusted.%该模型的研究是为了改善目前单目增强现实设备存在着视场小、成像不逼真、单目观察、适应人群窄等问题。模型系统选用高分辨率、宽色域、高集成度2 mm×17 mm OLED微显示器作为成像像源,大尺寸BS棱镜和凹面镜作为成像元件,合理控制图像放大倍率,提高视场;该系统可以实现高清晰稳定的单目及双目增强现实成像效果,具有多维的可调节度,包括调节放大倍数在1~∞内精确微调、眼距和双目图像合成角度等。

  1. The binocular vision of pediatric ocular trauma%儿童眼外伤治疗前后双眼视觉功能观察

    Institute of Scientific and Technical Information of China (English)

    许之娟; 刘桂香; 王玲; 张新爱; 李瑞凤

    2011-01-01

    Objective To observe the binocular vision in 76 pediatric ocular trauma, and analysis its relative factor. Methods There were 76 children(76 eyes) of 3 to 14 years old with ocular trauma. We examined their vision after primary wound repair. According the vision, we divided them into three groups: ≤0. 3,0.4-0.6 and ≥0.6. We divided the children of different ages into three groups according to the fusion or stereopsis using AIT-1000 synoptophore and Titmus stereogram:3 ~ 5 years old、6 ~ 7 years old、8 ~ 14years old. The vision was compared before and after treatment, the difference of binocular vision between different vision and different age were analysed. Results The binocular vision of difference visual:no patients had binocular vision if the vision less than 0. 3. 50 patients had a vision of more than 0. 4, only 39 patients have the function of fusion, 25 patients have far stereopsis,33 patients have near stereopsis. In the 39 patients with visual function of fusion, the difference between visual acuity of 0.4 ~0.6 and of ≥0.6 had statistical significance (P <0.05 ) ,the later one had more cases with visual function of fusion,far stereopsis and near stereopsis. The fusion 、far or near stereopsis of 6 ~7 years old group were less than the 3 ~5 years group and the 8 ~ 14 years group ( P < 0.05 ). The fusion 、far or near stereopsis of 3 ~ 5 years group had no difference compared with 8 ~ 14 years group ( P > 0.05). Conclusion The recovery of binocular vision is positive related to the recovery of vision. The recoveries of binocular vision of children aged 6 to 7 years were poor compared with the children aged 3 to 5 and children aged 8 to 14 years old.%目的 观察儿童眼外伤76例治疗后的双眼视功能,并对其相关因素进行分析.方法 3~14岁儿童眼外伤76例(76眼),于眼外伤一期修复后检查视力,分≤0.3,0.4~0.6和≥0.6 3组.使用AIT-1000型同视机及Titmus检查治疗后患儿的融合

  2. 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

  3. 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.

  4. 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。

  5. 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.

  6. 基于双目立体视觉的三维重建%3D Reconstruction Based on Binocular Stereovision

    Institute of Scientific and Technical Information of China (English)

    陈强

    2015-01-01

    三维重建是图像处理、计算机视觉、计算机图形学的一个重要研究领域。基于双目立体视觉的三维重建通过相机标定搭建一个对准的标准立体实验平台采集图像,进而对图像进行特征点检测与匹配找到待重建点,然后通过双目视觉原理计算三维坐标,最后进行纹理映射。根据真实图像的实验结果表明,具有较好的重建效果。%3D reconstruction is one of the important research fields in image processing, computer vision and computer graphics. 3D reconstruction based on binocular stereovision sets up a standard stereo experiment platform to collect images by camera calibration, finds reconstruction of point by feature point detection and matching, and does texture mapping. Experiment results of real images prove that it can achieve better reconstruction effect.

  7. Postnatal expression and distribution of Refsum disease gene associated protein in the rat retina and visual cortex: effect of binocular visual deprivation.

    Science.gov (United States)

    Ahn, Kyu Youn; Nam, Kwang Il; Kim, Baik Yoon; Cho, Chul Woong; Jeong, Sang Ki; Yang, Kun Jin; Kim, Kyung Keun

    2002-04-01

    Previously, phytanoyl-CoA alpha-hydroxylase-associated protein 1 (PAHX-AP1) was isolated as a novel neuron-specific protein to interact with Refsum disease (RfD) gene PAHX. Its expression in the brain increased after eyelid opening, and the elevated level was maintained through adulthood. In this report, to verify the hypothesis that light could trigger this increase, we have examined the developmental distribution pattern of PAHX-AP1 in rat retina and visual cortex, and changes of its expression by binocular deprivation. Northern blot analyses demonstrated PAHX-AP1 expression reached its highest level in the visual cortex and eyeball at 4 weeks after birth, and these levels were maintained through adult life. Two weeks after visual deprivation, its expression in the eyeball and visual cortex decreased compared with the control. In situ hybridization analyses of the retina showed that PAHX-AP1 expression was limited to the ganglionic cell layer at 10 days after birth, but expressed in the inner nuclear cell layer and extended to the outer nuclear cell layer at 2 and 3 weeks after birth, respectively. Two weeks after visual deprivation, however, it decreased in the ganglionic and inner nuclear cell layer, and disappeared in the rod and cone cell layers. In the visual cortex, strong signals of PAHX-AP1 were detected in layers IV and VI, and II-VI at 10 days and 2 weeks after birth, respectively. Its expression decreased after 2 weeks of visual deprivation. These results indicate that visual stimulation is essential for the maintenance of PAHX-AP1 expressions in the retina, especially in the rod and cone cell layers, and visual cortex, and suggest that PAHX-AP1 may be involved in the developmental regulation of the photoreceptor's function.

  8. Person following of binocular robot by extracting multiple features%多特征提取的双目机器人目标跟踪

    Institute of Scientific and Technical Information of China (English)

    王丽佳; 贾松敏; 李秀智; 王爽

    2013-01-01

    为了解决复杂环境下双目机器人的目标跟踪问题,提出多特征提取的方法。在机器人静止-目标运动模式下根据改进的步态光流图和视角识别目标并构造颜色直方图模板;在机器人运动-目标运动模式下利用扩展卡尔曼滤波器、基于自适应核函数的CamShift算法、基于Hu矩的头肩模型匹配算法提取目标的运动特征、颜色特征和头肩特征以实现目标跟踪。实验分析表明,所提出方法能够避免启动时手动框选目标,可以实现遮挡和背景与目标相似度高等复杂环境下的目标跟踪。%To solve the person following problem of binocular robot in complex environment, a method of extracting multi-feature is presented. For the stationary robot and moving target, the improved gait flow image and view are adopted to recognize the target, and then the color template is constructed. For both the moving robot and target, the motion information of the head and shoulder model and the color feature extracted by extended Kalman filter(EKF), the Hu moment based head and shoulder model matching method and the adaptive kernel based CamShift algorithm are used to track the target. The experiments show that this method avoids selecting the person manually, and tracks the person effectively in complex environment, such as backgroud and target high similarity, occlusion and so on.

  9. The study of P-VEP on binocular vision in cats%图形视觉诱发电位在猫双眼视觉研究中的作用

    Institute of Scientific and Technical Information of China (English)

    李林林; 温晏; 宫华青

    2013-01-01

    目的:通过建立猫不同种类的视觉破坏动物模型,探讨图形视觉诱发电位在双眼视觉研究中的作用.方法:健康家猫18只,于4周龄时随机建立正常、形觉剥夺性弱视及光学性斜视模型3组,每组动物各6只,分别在6周龄、10周龄和16周龄时记录各组动物的P波振幅和潜时.结果:随年龄增长,正常组P波潜时缩短,振幅增大,双眼振幅大于单眼反应之和;弱视组在10周龄时右眼振幅低于左眼,差异有统计学意义(P<0.05),潜时无统计学差异;16周龄时右眼(即弱视眼)振幅和潜时均低于左眼,双眼振幅表现为部分总和;光学性斜视组单眼间的P波潜时和振幅相比较以及与正常组相比无明显差异,双眼总和在10周龄和16周龄时小于单眼反应之和.结论:图形视觉诱发电位是评价动物双眼视觉的一种有效手段.%AIM: To evaluate the effect of pattern visual evoked potentioals (P-VEP) in the detection of binocular vision in cat models of visual dysfunction. METHODS: Eighteen 4-week-old healthy domestic cats were included. Twelve of them were used to establish models of monocular deprivation (6 cats) and optical strabismus (6 cats). The other six cats were used as controls. Their binocular visions were detected by P-VEP when they were 6, 10 and 16 weeks old, and the latency and the amplitude of P waves were recorded. RESULTS: With increasing age, the latency got shortened and the amplitude got enlarged in the control group. The binocular summation was larger than the summation of monocular amplitude. In the monocular deprivation group, the cats had lower amplitude in the right eye than the left eye at 10 weeks old, and the difference was statistically significant (P<0. 05); There was no statistically significant difference in the latency. When these cats were 16 weeks old, the latency and the amplitude of the right eye (the amblyopic eye) were obviously lower than the left eye, and partial binocular summation

  10. Observation of binocular vision after surgical corrections in V - pattern exotropia children%儿童V型外斜视手术前后双眼视觉功能变化观察

    Institute of Scientific and Technical Information of China (English)

    谢小华; 吕露; 戴鸿斌; 李祥芸; 石明华

    2015-01-01

    AlM:To observe the changes of binocular vision in V-pattern exotropia children before and after surgical correction, and the effect of training in reconstructing the binocular vision after surgical corrections.METHODS: Sixty V-pattern exotropia children were enrolled in this study and were divided into three groups according to their age:group A (4~6 years old), group B (7~9 years old), and group C (10~12 years old), 20 cases for each group. Patients received routine refraction and ophthalmic examinations. Distance and near deviation were measured by prism-covering method and synoptophore. The simultaneous perception and fusion were examined with a synoptophore, and the stereacuity was measured with stereograms ( Titmus) . The children who didn’t reconstruct binocular vision function 1wk after surgery received binocular vision training. The data were recorded before and 1 , 2, 4, and 8wk after surgery. RESULTS: Binocular vision significantly improved among the children after surgery in group A and B ( P0. 05). CONCLUSlON: V - pattern exotropia children can benefit from early surgical correction and training after surgery in reconstruct binocular vision.%目的::观察不同年龄组儿童V型外斜视手术前后双眼视觉功能变化及术后双眼视觉训练对术后双眼视觉建立的影响。方法:收集60例4~12岁V型外斜视患儿,按接受手术年龄分为三组:A组(4~6岁)、B组(7~9岁)、C组(10~12岁),每组20例。采用三棱镜加遮盖法及同视机检查33 cm及6 m处正前方及向上、向下注视的斜视度,以三棱镜度记录。同视机检查同时视、融合视,Titmus立体视图检查近立体视。对术后1 wk未能建立同时视功能的患儿给予双眼视觉训练,术后1,2,4,8 wk随访。结果:A、B 组手术前、后双眼视觉功能有明显差异(P0.05)。结论:早期手术矫正眼位正位,及术后积极有效的双眼视觉训练对于 V 型外斜视患者术后立体视的重建十分有利。

  11. Fast and Automatic Railway Building Structure Clearance Detection Technique Based on Mobile Binocular Stereo Vision%基于移动双目视觉的铁路建筑物限界快速自动检测方法

    Institute of Scientific and Technical Information of China (English)

    胡庆武; 陈智勇; 吴莎

    2012-01-01

    采用高速、高分辨率CCD相机以优于10-6s时间同步精度获取铁路建筑物限界的移动双目立体图像.提出了基于移动双目视觉测量模型,通过自检校多传感器系统标定和DGPS/IMU集成处理计算各双目图像严密的内、外方位元素,构建立体图像中各要素的空间相对关系.提出基于自动拟合计算的线路中心线空间位置的建筑物限界计算模型,与车辆限界相结合计算建筑物限界参数.设计并开发了一个基于双目视觉的铁路建筑物限界自动检测试验系统,进行铁路建筑物限界自动检测试验,对其精度进行分析和讨论,结果表明可达到标准规定的技术指标.%The synchronization imaging technique with high speed and high resolution CCD cameras is presented to obtain the mobile binocular stereo image of the clearances of railway building structures. With the unit timing board, the binocular images can obtain synchronized time to GPS/IMU sensors less than 10~6s. The photo-grammetry surveying model based on mobile binocular vision is proposed. With the sensor calibration parameters based on self-calibration and the train position and attitude from DGPS/IMU integration, all the objects in the stereo images can be restricted within a precise formulation. The intelligent image processing algorithm is designed to automatically extract railway from the binocular sequence images to calculate the railway center-line. The railway building structure clearance calculation model with the railway centerline is presented to calculate the building constructure clearance parameters within the railway clearance standards. The experiment system of railway building structure clearances is designed with the proposed methodology for project applications. The accuracy of building structure clearance detection is less than 0. 03m which satisfies the railway clearance measurement standards.

  12. 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。

  13. 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。

  14. 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.

  15. 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 .

  16. 屈光参差性弱视儿童治愈后的双眼视觉研究%Binocular vision in cured anisometropic amblyopia

    Institute of Scientific and Technical Information of China (English)

    林楠; 王京辉; 孙省利; 董芳

    2012-01-01

    Objective To investigate the binocular vision change in cured anisometropic amblyopic children and normal children. Design Retrospective case series. Participants 74 children with anisometropic amblyopia and 74 normal children. Methods Binocular vision of 74 anisometropic amblyopic children with best distance acuity ≥0.9 and 74 normal children were tested with synoptophore and stereogram designed by Yan Shao-ming. Main Outcome Measures Simultaneous perception, distance fusion range, distance qualitative stereopsis and near zero disparity. Results (1) Distance qualitative stereopsis in cured anisometropic amblyopic children was worse than normal children(χ2=11.331 ,P=0.001), simultaneous perception (χ2=1.855 ,P=0.173) and distance fusion range (χ2=1.012,P= 0.603) had little difference between them. (2) Near zero disparity in cured anisometropic amblyopic children was obviously worse than normal children (χ2=27.759,P=0.000). (3) The milder the degree of anisometropic amblyopia, the more prominent the improvement of the near zero disparity (χ2=17.116,P=0.009). While simultaneous perception (x2=0.879,P=0.644),distance fusion range(χ2=7.930,P= 0.094), distance qualitative stereopsis (χ2=2.854, P=0.240) had little difference. Conclusion Anisometropic amblyopia affects the development of stereoacuity critically. The stereoacuity of anisometropic amblyopic children with best distance acuity ≥0.9 after treatment is still worse than normal children. The more severe the degree of anisometropic amblyopia, the more prominent the effect of the near zero disparity.%目的 了解屈光参差性弱视儿童治愈后双眼视觉状况.设计回顾性病例系列.研究对象屈光参差性弱视儿童74例,正常儿童74例.方法 采用同视机和颜少明《立体视觉检查图》对74例经治疗矫正视力已≥0.9的屈光参差性弱视儿童和74例正常儿童的双眼视觉功能进行检测.主要指标同时知觉、远融合范围、定性

  17. 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

  18. Comparison and evaluation of the surgical effect and binocular vision change before and after surgery for intermittent exotropia%双眼视觉在间歇性外斜视手术前后变化及手术效果相关研究

    Institute of Scientific and Technical Information of China (English)

    华文娟; 顾永辉; 徐丹丹

    2015-01-01

    AIM: To investigate the preoperative binocular visual function of intermittent exotropia and the rebuilding and recovery of the postoperative binocular visual function, and analyze the effect of binocular visual function on orthophoria after surgery. METHODS:From January 2011 to January 2014, 47 basic intermittent exotropia patients caming for treatment were collected in the clinical data. The changes in their near stereopsis, binocular visual function, binocular fusion and distance stereopsis after operations were recorded in the form of data. The preoperative binocular vision and the postoperative rebuilding were analyzed and contrasted with each other. In addition, the effect on the postoperative maintaining of orthophoria due to the existence, recovery and rebuilding of binocular visual function were observed. RESULTS:Intermittent exotropia patients got damage in different levels on their binocular visual functions, especially on distance stereopsis, which was the heaviest and earliest. After the operation, all functions were obviously recovered and reconstructed and the improvements were statistically significant compared against those before the operation (P CONCLUSION: The intermittent exotropia cause damage to the stereopsis which happened the earliest. Obvious recovery and reconstruction of binocular visual function can be observed after the surgery. A relatively good preoperative binocular visual function may lead to the increase in the ratio of orthophoria or cure the intermittent exotropia. Performing an operation when distance stereopsis is damaged can increase the success rate for the surgery and reduce the recurrence rate.%目的:观察间歇性外斜视术前双眼视功能状态和术后双眼视功能的重建与恢复,分析双眼视功能对术后眼位正位的影响。  方法:收集我院2011-01/2014-01收治的47例基本型间歇性外斜视患者的临床资料,记录术前术后近立体视、双眼同时视、融合功能及

  19. 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.

  20. New progress in the treatment of amblyopia and related binocular visual impairment%弱视及弱视相关双眼视功能损害治疗的新进展

    Institute of Scientific and Technical Information of China (English)

    李蕾; 付晶

    2016-01-01

    人眼在视觉发育期由于单眼斜视、未矫正的屈光参差、高度屈光不正及形觉剥夺引起的单眼或双眼最佳矫正视力低于相应年龄的视力为弱视;或双眼视力相差2行及以上,视力较低眼为弱视。弱视在视觉敏感期给予正确治疗可治愈,然而一旦错过治疗时机则会造成终生视力低下;且弱视还会影响双眼视觉功能。因此,弱视的治疗一直是眼科研究的热点问题。目前,弱视的主要方法包括屈光矫正、遮盖疗法、药物治疗、压抑疗法、手术治疗(针对形觉剥夺性弱视)、综合治疗等。近年来,双眼视功能的重建在弱视治疗评价中也逐渐受到重视。本文中笔者在回顾国内外相关文献的基础上,对弱视的治疗方法及最新进展做一综述。%The best corrected visual acuity of monocular or binocular vision in patients with amblyopia is lower than that in normal eyes .It is in visual development period ,as a result of the monocular strabismus,uncorrected anisometropia, highly refractive errors, form deprivation induced.In addition, binocular vision is a difference of 2 lines, low vision eye is amblyopia .Amblyopia in the visual sensitive period to give the correct treatment can be cured , but once missed the opportunity of treatment will cause lifelong amblyopia;and the amblyopia will affect the binocular visual function .Therefore , the treatment of amblyopia has been a hot issue in the Department of Ophthalmology .At present, the main methods of amblyopia including refractive correction , cover therapy , medicine therapy , depression therapy , surgical treatment ( for form deprivation amblyopia ), comprehensive treatment, and so on.In recent years, the reconstruction of binocular visual function has been paid more and more attention in the treatment of amblyopia .On the basis of reviewing domestic and foreign literatures , the author reviewed the treatment methods and the latest

  1. 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.

  2. 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.

  3. The effect of different ways of spectacles wearing on binocular vision function in low myopia%框架眼镜配戴方式对低度近视患者视功能影响

    Institute of Scientific and Technical Information of China (English)

    刘文兰; 王莉; 杨扬; 刘珍

    2015-01-01

    binocular vision function and the degree of asthenopia in low myopia,then to find a right way to correct low myopia.Methods Between September 2012 and February 2013,60 Xi'an Medical University students with low myopia (≤-3.00DS) were divided into 3 groups of continued spectacle wearing (20 students),interrupted spectacle wearing (20 students) and non spectacle wearing (20 students).The degree of asthenopia was investigated with Visual Quality Scale and the parameters of binocular vision function were measured after refractive error was corrected.Chi squar test was used to analyze the difference of the rate of asthenopia and binocular dysfunction among three groups.Results The binocular dysfunction cases in continued spectacles wearing group,interrupted wearing group and no wearing group were 6,15 and 17 respectively.The rate of binocular dysfunction during the continued spectacles wearing group showed significantly low compared with that of interrupted wearing group (x2=8.120,P =0.010) and no wearing group (x2=12.379,P =0.001).The asthenopia cases in continued spectacles wearing group,interrupted wearing group and no wearing group were 5,13 and 14 respectively.The rate of asthenopia during the continued spectacles wearing group showed significantly low compared with that of no wearing group (x2=8.120,P =0.010),there was no statistical significance between no wearing group and interrupted wearing group (x2=6.465,P =0.025) and between interrupted wearing group and continued spectacles wearing group (x2=0.114,P =1.000).Conclusions Compared with continued spectacles wearing,people with low myopia who interrupted wearing and non wearing spectacles tend to be more likely suffer from asthenopia and binocular dysfunction,it is proved that people who has low myopia should better best correct it and wearing spectacles continually.

  4. Outcomes of binocular vision after surgical corrections in concomitant strabismic patients%共同性斜视患儿手术前后三级视功能的临床观察

    Institute of Scientific and Technical Information of China (English)

    曾仁攀; 梁小琼; 王国平; 王丹玲

    2014-01-01

    Objective To observe the changes of binocular vision in concomitant strabismic patients before and af -ter surgical correction , and to discuss the importance of binocular vision reconstruction for concomitant strabismic patients . Methods Thirty-seven patients with constant comitant strabismus were enrolled .Patients received routine refraction and ophthalmic examinations .Distance and near esotropia were measured by prism-covering method .The simultaneous percep-tion and fusion were examined with a synoptophore , and the stereacuity was measured with stereograms .The patients who have ametropia must wear glasses when being examined .These data were recorded before surgery and 1 month, 3 months, and 6 months after surgery.Results Before surgery, eight patients exhibited simultaneous perception (21.6%), and sev-en patients showed binocular fusion (18.9%).The average fusion range was 1.90 ±4.15○.No patient had measurable stereopsis.Simultaneous perception significantly improved among the patients 1 month after surgery ( P <0.05).At 3 month and 6 month, simultaneous perception as well as binocular fusion and stereopsis all significantly improved ( P <0.05).Conclusion The loss of binocular vision in patients with comitant strabismus is severe .After surgical correction, binocular vision could improve significantly .Patients with constant comitant strabismus in China usually have longer disease course and are treated at older ages .Early screening , diagnosis and surgical correction for strabismus should be advocated .%目的:观察共同性斜视患者手术前后双眼视觉功能的变化,探讨手术矫正在共同性斜视患者双眼视觉功能重建中的重要性。方法收集了37例共同性斜视患者,手术前后分别进行眼部常规检查,屈光检查和三棱镜加交替遮盖法测定远、近斜视度;同时视、融合功能采用同视机检测,立体视功能采用颜少明编绘的《立体视觉检查图》检测。有屈光

  5. 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

  6. 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 .

  7. 基于光栅双目视觉的手掌重构与实现%Hand-shape reconstruction and implementation method based on raster binocular system in vision metrology

    Institute of Scientific and Technical Information of China (English)

    曹淼龙; 李强; 姜文彪

    2015-01-01

    Aiming at the characteristics of complicated texture epidermis and elasticity deformation of hand and palm form ,a reconstruction and implementation method for building the model of hand‐shape based on the technology of raster binocular system in vision metrology is proposed . The 3D vision measurement system is employed to calibrate the character parameter ,attribute parameters and relative position of cameras in left and right side .Firstly , by two finished calibration cameras performance ,we acquire data of photographed multi images from the hand‐shape model with raster binocular system and global data optimization registration are accomplished . T hen on this basis , the massive original point‐clouds data are compiled .Finally ,the hand shap model is simulated with numerical control and is also verified by practical processing . T he experimental results demonstrate that the reconstruction model with non‐contact measuring method is of high precision ,good practicality and valuable to be referenced and promoted in application .%针对手部掌形的表皮纹理复杂性和弹性易形变等特点,提出了一种以光栅式双目三维视觉技术对手部掌形模型进行重构及实现的方法。首先对左右侧相机的属性参数和相对位置进行标定,并利用多方位光栅扫描的图像作优化拼接,再对海量原始数据点云进行编辑、三角形和曲面片化处理,最后实现手部掌形模型的数控模拟和实际加工验证。试验结果表明,采用高精度的非接触式测量能快速完成逆向实物加工,该方法具有借鉴和应用价值。

  8. 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

  9. 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.

  10. 角膜塑形镜矫正青少年近视性屈光参差对双眼视觉的影响%Research on binocular vision after wearing orthoker-atology lens in adolescent myopic anisometropia

    Institute of Scientific and Technical Information of China (English)

    张春侠; 李自芳; 陈梅珠

    2015-01-01

    Objective To analyze the binocular vision after wearing orthokeratology lens in adolescent myopic anisometropia.Methods Twenty-three patients of retrospective cases with binocular myopic anisometropia more than 2.50 diopters received orthokeratology lens.All patients were followed 12-50 months,to observe the uncorrected visual acuity (UCVA),best-spectacles corrected visual acuity (BSCVA),refraction,binocular vision before and after wearing orthokeratology lens.Results The uncorrected visual acuity was improved significantly,the BCVA of 31 eyes (86.0%) reached or more than BSCVA.In the degree of anisometropia,there was a significant difference between before treatment (3.08±l.42)D and post-treatment (0.36±0.40)D.The myopia degree increased (0.22±0.38)D in high degree myopic eye after one year treatment,(0.16±0.30)D in low degree myopic eye.The short distance stereopsis vision after wearing orthokeratology lens was significantly higher than that before treatment (x2=27.22,P <0.01).And it was also significantly higher than that before treatment with corrected glasses (x2=15.51,P <0.01).Conclusions Orthokeratology lens can improve the UCVA,control the development of myopia and resume the binocular vision for adolescent myopic anisometropia.%目的 探讨角膜塑形镜矫正青少年近视性屈光参差对双眼视觉的影响及临床价值.方法 回顾性临床分析研究.对2009年10月至2013年4月在南京军区福州总医院接受角膜塑形镜治疗,资料完整的23例(36只眼)屈光参差患者,持续戴镜12~50个月进行随访,观察治疗前及配戴角膜塑形镜裸眼视力(UCVA)、最佳矫正视力(BSCVA),屈光度数变化及双眼视觉.结果 配戴角膜塑形镜1年时裸眼视力(UCVA)达到或超过治疗前最佳矫正视力(BSCVA)的百分比为:86% (31/36).治疗前双眼屈光参差度数为(3.08±1.42)D,配戴角膜塑形镜为(0.36±0.40)D,较治疗前明显降低.配戴角膜塑形镜近视加深度数1

  11. Update on binocular form deprivation amblyopia: mechanisms and treatment%提高对双眼形觉剥夺性弱视发病机制和治疗进展的认识

    Institute of Scientific and Technical Information of China (English)

    阴正勤; 余涛

    2010-01-01

    弱视的发生、发展与视觉发育可塑性关键期密切相关,而形觉剥夺所致视皮层功能异常引起的弱视最严重,错过一定治疗时机将很难治愈.近年来关于双眼形觉剥夺对视皮层可塑性机制影响的研究为成年弱视治疗提供了理论基础.%The onset and development of the amblyopia is related to the critical period of the visual cortex plasticity, while the form deprivation amblyopia is the most serious. Amblyopia of elder children and adults can not be cured if the best timing is missed. Recent researches on the mechanisms of visual cortical plasticity and binocular form deprivation have given a hint for adult amblyopia treatment.

  12. 基于2D-3D双目运动估计的立体视觉定位算法%Stereo Visual Localization Algorithm Based on 2D-3D Binocular Motion Estimation

    Institute of Scientific and Technical Information of China (English)

    许允喜; 蒋云良; 陈方

    2011-01-01

    Motion estimation algorithm of stereo vision is one of the important factors which affect the accuracy of stereo visual localization. The traditional 3D-3D motion estimation is greatly affected by noise, so the accuracy of algorithm is not high. We propose a new stereo visual localization algorithm based on 2D-3D binocular motion estimation. In our method, 2D image projection coordinates is directly used instead of 3D coordinates of feature after motion. Firstly, EPnP motion estimation is applied to determine matching inliers and initial motion parameters. We propose 2 x 2D-3D motion parameters optimization method based on Levenberg-Marquardt algorithm and geometric constraints between the 2D projection of binocular cameras. Optimal 2D-3D motion estimation is achieved by minimizing the error between the observed 2×2D image points and the re-projected 2×2D image points of stereo cameras from the reconstructed 3D features. Simulated experiment and outdoor real experiment show that our method performs well in accuracy and robustness, and are better than traditional 3D-3D methods.%运动估计算法是影响立体视觉定位精度的重要因素,传统的3D-3D运动估计算法受噪声影响很大,计算精度不高.本文提出了一种基于2D-3D双目运动估计的立体视觉定位算法.算法不使用运动后的特征点3D坐标,而直接利用其2D图像投影坐标.首先,利用EPnP运动估计算法确定匹配内点和初始运动参数.接着,利用双目相机之间的2D投影几何约束,提出了基于Levenberg-Marquardt算法的2×2D-3D运动参数优化算法,利用确定的匹配内点和初始运动参数,使特征点在立体相机左右图像上的再投影误差最小,从而达到最优的立体相机2D-3D运动估计.仿真实验和户外真实实验表明:本文算法获得了很高的计算精度、鲁棒性,大大优于传统的基于3D-3D运动估计的立体视觉定位算法.

  13. 基于视觉原理的运动物体空间姿态测量技术研究%Study on Measuring the Pose of the Moving Object Based on Binocular Vision

    Institute of Scientific and Technical Information of China (English)

    孙增玉; 梁雅军; 刘柯; 宋金城; 郭磊

    2014-01-01

    针对物体运动姿态的测量问题,以提高姿态求解方法的便捷性和准确性为目的,研究了一种基于双目视觉相机高速摄影测量物体姿态的测试技术。为实现该测量,使用高速相机获取同步影像,利用特征点间的几何约束关系,通过姿态优化算法确定被测物体空间姿态。试验结果表明:该方法正确、可靠,测量频率达到100帧/s,姿态角测量误差小于0.04°。%To the question of measuring the moving object pose , a high speed spatial pose measure-ment system based on binocular vision photography was designed .The system can record the course with high precision synchronization .Geometry constraint relation of the special markets and optimization algo-rithm based on coordinates of multi-points were used in the pose algorithm of the moving object .Experi-mental results and theoretical analysis prove that the pose measurement method is correct and reliable . The frequency of the pose measurement system is 100 frames per second .The measurment error of the pose angle is less than 0.04°.

  14. The Research of Automatic Pick-up Equipment of Hump that Based on Stereo Binocular Vision Technology%基于双目立体视觉技术的驼峰自动摘钩设备研究

    Institute of Scientific and Technical Information of China (English)

    何霄; 李国宁; 翟琛

    2013-01-01

    在驼峰解体作业中,国内外均采用人工摘钩的作业方式.针对驼峰自动摘钩设备,提出了用计算机视觉技术解决目标车钩捕捉的问题.根据双目视觉原理,选取两个摄像机从不同角度拍摄的图像,通过对图像的预处理得到能表现图像特征的角点,然后对两幅图像中的特征点进行特征匹配;根据视差原理,得出目标物体的深度信息,完成物体三维立体坐标的计算,设备能以此信息为依据完成自动摘钩作业.%In the disintegration work of hump, it used to adopt the mode of operation of artificial pick-up at home and abroad. The automatic pick-up equipment of hump, and present that using computer vision technology to solve the problem of capturing the car coupler is mainly accorded. According to the principle of binocular vision, two pictures that have been shooting by two camera from different angles is selected. Through the pretreatment to pictures picture, the corner that can display the characteristic of picture be can got, then proceed feature matching to the feature points in two pictures. On the basis of parallax principle, the depth information of the target object and finish the calculation of 3d coordinates of the object are can got, so the equipment can finish automatic pick-up work in the light of the 3d information.

  15. Digital Calibration System of Binocular Photoelectric Equipment Optical Axis Parallelism%双目光电装备光轴平行性数字化检校系统设计

    Institute of Scientific and Technical Information of China (English)

    史云胜; 刘秉琦; 应家驹; 姜玉海

    2012-01-01

    设计了一种多光谱双目光电装备光轴平行性数字化检校系统。利用平行光管产生无限远白光、微光、红外目标,平行光经双目光电装备、光轴平移装置,将两路光线入射到面阵CCD上,目标图像经CCD、图像采集卡转换成数字图像信息送入计算机,利用软件算法得到光轴误差量,参考所建立的光电装备数学模型,给出光轴校正方案,利用辅助工具完成光轴平行性校正。该系统适用于多种双目光电装备,能够实现自动化检测,并给出数字化的光轴误差量,具有良好的通用性和可扩展性。%For the calibration system, a collimator is used to give white target, dim light target or IR target at infinity. Through the binocular photoelectric equipment and optical axis translation device, the two parallel lights will be incident to the area array CCD, and the target images are converted into digital image information by the CCD and frame grabber, which will be put into the computer, with which the optical axis deviation can be calculated. Then by referring to the mathematical model, the computer can give the optical axis correction program and assist in completing the parallel correction. The system is suitable for a variety of optoelectronic equipments; it can realize auto detection and display the optical axis deviation in digital form, obtaining good versatility and expansibility.

  16. Based on Binocular Vision of Mobile Robot Obstacle Avoidance Algorithm Simulation%基于双目视觉的移动机器人避障算法仿真研究

    Institute of Scientific and Technical Information of China (English)

    何燚; 张翼飞

    2013-01-01

    针对当前超声波定位的机器人避障技术中,只能感知外围的单一信息,在多机器人通信或者外围存在信号串扰的前提下,信息转化测距结果存在较大误差,存在避障盲区的问题,提出一种视觉多图像信息融合的机器人避障算法,通过双目立体视觉采集机器人的实际图像信息,运用像素自适应融合方法最大程度的采集视觉信息,归一化后的视觉信息带入A*算法进行最优路径的选择,克服单一信息选择中路径计算的弊端,建立多信息约束的路径搜索模型,最大化的解决视觉避障中的干扰问题.后期的计算机仿真结果表明,与传统的测距避障算法相比,有效提高了算法的抗噪性能和避障准确性,为移动机器人避障优化提供了依据.%In view of the current based on ultrasonic positioning of the robot obstacle avoidance method, can only perception peripheral single information, in multi - robot communication or peripheral existing signal crosstalk, under the precondition of information transformation ranging results there is A big error, there exists obstacle avoidance blind area of the problems, the article proposes A kind of multiple image based on visual information fusion robot obstacle avoidance algorithm, through the binocular stereo vision acquisition robot actual image information, the use of pixel adaptive fusion method maximum acquisition visual information, normalization of visual information into the A * algorithm is optimal path choice, overcome A single information in the choice of the disadvantages of path is calculated and establish the multiple information constraint path search model, to solve the maximum visual obstacle a-voidance of interference problem. Later the computer simulation experiments to prove and traditional ranging obstacle avoidance algorithm, the algorithm improve the antinoise performance and obstacle avoidance accuracy, improvement effect is obvious..

  17. 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。

  18. Hardware-in-the-loop Simulation System of UUV Obstacle Avoidance Based on Binocular Vision%基于双目视觉的UUV避障半实物仿真系统

    Institute of Scientific and Technical Information of China (English)

    严浙平; 姜玲; 王晓娟; 赵玉飞

    2012-01-01

    The sea trials for the obstacle avoidance research of an unmanned underwater vehicle (UUV) are expensive and high-risk. To facilitate the research of automatic obstacle avoidance of an UUV in laboratory, a hardware-in-the-loop simulation system of UUV obstacle avoidance has been developed based on binocular vision, where the multi-degree of freedom test platform is used to simulate the motion of the UUV, and the double-stereo vision system is used to simulate forward looking sonar. In this paper, the structure and data stream of the system are discussed. The key technologies for vision subsystem and the software scheme for UUV model subsystem are also described. Joint simulation tests were conducted by adopting rule-based obstacle avoidance approach. Experimental results show that the system has the advantages of simple structure and convenient application, and it can be used in demonstration, validation, and evaluation of obstacle avoidance path plan.%由于无人水下航行器(UUV)避障研究的实物海洋试验成本高且风险较大,故针对在试验室进行UUV自主避障规划的需求,利用双目视觉展开了UUV避障半实物仿真试验系统的设计研究,包括多自由度运动台架模拟UUV的运动,双目摄像机代替前视声纳作为避障传感器.阐述了实物双目视觉子系统的关键技术和UUV模型子系统的软件实现方法,以及系统的体系结构、数据交换方法,并进行了基于规则的避障仿真联调试验,结果表明,该系统结构简单,试验实施便利,可作为演示、验证和评估避障路径规划正确性和有效性的实用手段.

  19. Study of the affection to binocular visual function by the perceptual learning for children with intermittent exotropia%知觉学习对于间歇性外斜视儿童视功能影响的研究

    Institute of Scientific and Technical Information of China (English)

    俞佳伟; 梁斗立; 于雪冰; 顾若姝; 熊壮; 张玮玮

    2012-01-01

    目的 观察知觉学习训练对于儿童间歇性外斜视双眼视功能的影响.方法 42例间歇性外斜视患儿,行知觉学习训练.训练前及训练1个月、2个月、3个月后应用同视机检测Ⅰ级、Ⅱ级、Ⅲ级视功能,Titmus立体视觉检查图观察近立体视,同时进行间歇性外斜视斜视角检查.并对数据进行统计学分析.结果 42例患儿中,经同视机检查训练前Ⅰ级视功能20例,训练后1个月、2个月、3个月分别增加到24、27、32例,训练前与训练3个月后比较,差异有统计学意义(P<0.05);训练前Ⅱ级视功能20例,训练后1个月、2个月、3个月分别增加至23、26、30例,训练前与训练3个月后比较,差异有统计学意义(P<0.05);训练前Ⅲ级视功能18例,训练后1个月、2个月、3个月分别增加至23、25、30例,训练前与训练3个月后比较,差异有统计学意义(P<0.05);Titmus立体视觉检查图发现,训练前近立体视19例,训练后增加至21、23、29例,训练前与训练后3个月后比较,差异有统计学意义(P<0.05).训练前远方斜视角为28.33△±11.15△,训练1个月、2个月、3个月后分别为27.81△±10.87△,27.98△±11.28△,27.69△±11.56△,与训练3个月后比较,差异有统计学意义(P<0.05).结论 知觉学习训练治疗有助于间歇性外斜视患儿双眼视功能的重建,减少斜视度,对于未达到手术指证患者可以应用.%Objective To investigate the effect of binocular visual function of children with intermittent exotropia after perceptual learning. Methods A total of 42 children with intermittent exotropia were taken. Synoptophore was used to detect visual function at I stage, II stage and at HI stage. Titmus stereogram was used to detect near stereopsis. We also check the strabismus angle of these patinets. All data were recorded before learning and 1, 2 and 3 months after learning, then be statistically analyzed. Results In 42 children with intermittent

  20. 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...

  1. 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

  2. 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

  3. Binocular vision changes after phakic posterior chamber implantable collamer lens implantation%有晶状体眼后房型人工晶状体植入术后双眼视觉的变化

    Institute of Scientific and Technical Information of China (English)

    王晓贞; 付晶; 王京辉; 赵世强

    2015-01-01

    目的 评价有晶状体眼后房型人工晶状体(PPC-ICL)植入治疗高度近视术后患者双眼视觉的变化.方法 自身对照研究.行PPC-ICL植入术治疗高度近视患者42例,分别于术前和术后6个月行同视机的同时视、双眼融合、远立体视检查,采用颜少明《立体视觉检查图》检测近立体视锐度.采用Fisher's精确概率法对术前和术后6个月以上各参数进行统计分析.结果 术后6个月同时视功能与术前相比差异无统计学意义.远融合范围与远立体视锐度较术前有明显改善,差异有统计学意义(x2=0.357,P<0.01;x2=0.276,P<0.05).术后6个月与术前相比中心凹立体视功能和周边立体视功能较前改善,但差异无统计学意义.立体视盲者术后6个月较术前明显减少,差异有统计学意义(x2=0.279,P<0.05).结论 PPC-ICL植入术后患者同时视、双眼融合、远立体视功能及近立体视功能较术前明显改善.%Objective To evaluate the changes in binocular vision after phakic posterior chamber implantable collamer lens (PPC-ICL) implantation for high myopia.Methods This self-control study included 84 eyes of 42 patients with high myopia who underwent PPC-ICL implantation surgery.Simultaneous perception,fusion range,and distance and near stereopsis were tested before and 6 months after surgery with a synoptophore and stereogram designed by Yan Shaoming.Results There was no significant difference in simultaneous perception before surgery compared to 6 months after surgery,while the differences in fusion range and distance stereopsis were statistically significant (x2=0.357,P<0.01 and x2=0.276,P<0.05).There were no significant differences in foveal stereopsis and peripheral stereopsis before surgery compared to 6 months after surgery,but there was a significant difference in stereo blindness (x2=0.279,P<0.05).Conclusion Simultaneous perception,fusion range,and distance and near stereopsis after PPC-ICL implantation

  4. 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

  5. 儿童内斜视矫正术后双眼单视的建立及影响因素%Factors influencing binocular vision in children with successful surgical alignment for esotropia

    Institute of Scientific and Technical Information of China (English)

    杜宇; 孔香云; 王利华

    2012-01-01

    目的 观察和分析内斜视儿童眼位矫正术后双眼单视功能的建立情况及其影响因素.方法 回顾性系列病例研究.收集2008年11月至2011年9月间在山东大学附属省立医院眼科中心行共同性内斜视矫正手术并且术后随访眼位正位(≤±8△)的连续性病例111例.采用手电筒式Worth四点灯评估患儿的中心融合和周边融合;采用Titmus立体视图测定患儿的立体视锐度.采用x2检验比较不同内斜视类型之间周边融合建立的差异;采用Logistic回归分析内斜视类型、弱视治疗时间、手术年龄、两眼屈光参差差值、术后斜视度对周边融合建立的影响,并采用优势比(OR)进行比较.结果 111例内斜视儿童中,术后获得周边融合者68例(61.3%),其中获得中心融合者6例(5.4%);56例(50.5%)建立了不同程度的立体视.手术年龄(b=-0.842,P<0.01)、弱视治疗时间(b=-0.135,P<0.05)、最终随访的斜视度(b=-1.305,P<0.05)与术后周边融合的建立呈负相关;两眼屈光参差差值与术后周边融合的建立不相关(b=-19.670,P>0.05).4种内斜视类型之间术后周边融合建立的差异有统计学意义(x2=-15.977,P<0.01),周边融合建立的困难程度依次为先天性内斜视(OR=1.0)、非调节性内斜视(OR=3.008)、部分调节性内斜视(OR=4.475)、高AC/A型内斜视(0R=82.217).结论 内斜视儿童手术年龄愈早、术前弱视治疗时间愈短、术后斜视度愈小,术后愈易建立周边融合;4种内斜视类型中,建立周边融合的难易顺序依次为先天性内斜视、非调节性内斜视、部分调节性内斜视、高AC/A型内斜视.%Objective To investigate the binocular vision achieved in children after successful surgical alignment for esotropia and to identify clinical factors that may be associated with the outcome.Methods Consecutive cases surgically aligned within ±8 PD of orthotropia were consecutively reviewed during a follow

  6. 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.

  7. Comparative study on binocular fusion and stereoacuity of patients with intermittent exotropia before and after surgery%间歇性外斜视手术矫正前后融合和立体视功能对照研究

    Institute of Scientific and Technical Information of China (English)

    赵淑静; 王利华

    2013-01-01

    Objective To compare the binocular fusion and stereoacuity achieved in patients before and after successful surgical alignment of intermittent exotropia.Methods Retrospective case series study.Consecutive cases of 114 patients of intermittent exotropia with successful surgical alignment (+5 ~-10PD) in the Eye Center of Provincial Hospital affiliated to Shandong University were retrospectively recruited.Titmus stereogram was used to evaluate the near stereoacuity and Worth 4dots flashlight test was used to evaluate the central and peripheral fusion of the patients before and after successful surgical alignment of intermittent exotropia.Prism and alternative cover test was used to evaluate the deviation of the patients fixating at accommodative targets of 6m and 33cm.Based on the angles examined after surgery,114 patients were divided into 4 groups (Group A:+1~+ 5PD; Group B∶ 0 PD; Group C∶-1~-5PD; Group D∶-6~-10PD).Chi-square test and nonparametric Wilcoxon signed rank test were used to compare the binocular fusion and stereoacuity of patients respectively before and after surgery,P <0.05 were considered statistically significant.Results There were significant difference statistically between binocular fusion evaluated before surgery and that after surgery in patients with intermittent exotropia (P =0.000).Binocular fusion evaluated after surgery was significantly different among 4 groups (P =0.004).There was statistical significance between stereoacuity examined before and after surgery (P =0.000).Stereoacuity examined before and after surgery was not significantly different in Group A (P =0.336),others had statistical significance (P =0.001).Conclusions There is significant improvement in binocular fusion and stereoacuity after successful surgical alignment of patients with intermittent exotropia,compared with that before surgery.%目的 对间歇性外斜视患者手术矫正前、后的双眼融合功能和立体视

  8. The Effect of Orthokeratology Lens for the Correction of Juvenile Myopia Anisometropia on Binocular Vision%角膜塑形镜矫正青少年近视性屈光参差对双眼视觉的影响

    Institute of Scientific and Technical Information of China (English)

    纪冬梅

    2016-01-01

    目的:探讨角膜塑形镜矫正青少年近视性屈光参差对双眼视觉的影响。方法对在我院接受角膜塑形治疗的32例(50只眼)近视性屈光参差患者的临床资料进行回顾分析,比较患者治疗前后裸眼视力屈光参差度以及屈光度等的变化。结果治疗1年后裸眼视力达到或超过治疗前最佳矫正视力1.0以上45只眼,占90.0%。治疗前后患者屈光参差度分别为(3.12±1.21)D和(0.35±0.37)D,治疗前后差异有统计学意义(P<0.05)。治疗后近视加深速度与治疗前比较有所减缓。结论青少年近视性屈光参差患者接受角膜塑形治疗可有效改善患者双眼视觉功能。%Objective To investigate the influence of orthokeratology lens in correction of juvenile myopia anisometropia on binocular vision.Methods In our hospital accepted clinical data of orthokeratology treatment of 32 cases(50 eyes)with myopia refractive anisometropia patients who were retrospectively analyzed,compared before and after treatment in patients with naked eye visual acuity of anisometropia and refraction changes.ResultsAfter 1 years of treatment,the visual acuity reached or exceeded 45 of the best corrected visual acuity before treatment 1 years later,the proportion was 90.0%. Before and after treatment in patients with anisometropia were(3.12±1.21)D and(0.35±0.37)D,there were significant differences before and after the treatment(P<0.05). After the treatment,the rate of myopia deepening was somewhat slower than before treatment.Conclusion Juvenile myopia anisometropia patients undergoing orthokeratology therapy can effectively improve the patients with binocular visual function.

  9. The application of binocular indirect ophthalmomicroscope combined with anterior chamber maintainer in vitrectomy for complicated vitreoretinopathy%非接触双目间接眼底显微镜联合前房灌注在复杂玻璃体视网膜病变术中的应用

    Institute of Scientific and Technical Information of China (English)

    王永梅; 王莹; 楚艳华; 韩泉洪

    2012-01-01

    目的 观察使用非接触双目间接眼底显微镜(BIOM)联合前房灌注系统(ACM)行玻璃体切割术处理复杂玻璃体视网膜病变的临床疗效.方法 6例(6只眼)复杂玻璃体视网膜病变行玻璃体切割术时,为了避免医源性的脉络膜视网膜损伤,采用前房灌注来维持眼压,晶状体摘除及前部玻璃体切割后,切换至BIOM行玻璃体视网膜手术.临床随访3~11月,评估手术疗效及并发症.结果 6例BIOM联合ACM的玻璃体切割术在操作中未见明显困难.术后5例视力提高,1例无变化.主要长期并发症为低眼压、前部PVR、视网膜前膜.4例行硅油取出术后,视网膜在位. 结论 采用BIOM联合ACM行玻璃体切割术治疗复杂玻璃体视网膜病变安全、有效,在实践中具有可行性.%Objective To evaluate the clinical results of vitrectomy by using binocular indirect ophthalmomicroscope (BIOM) combined with anterior chamber maintainer (ACM) for complicated vitreoretinopathy.Methods Six cases (6 eyes) of complicated vitreoretinopathy were undergone vitrectomy,during which ACM was used to maintain intraocular pressure and prevent from iatrogenic injury of choroid and retina.After lens and anterior vitreous removal,vitrectomy was completed through a BIOM observation system.The follow-up time ranged from 3 months to 11 months.The effects and complications were analyzed.Results No obvious drawback was noticed during the 6 cases vitrectomy by using BIOM and ACM combination.The visual acuities improved in 5 cases and remained stable in 1 case after operation.The major long-term complications were hypotony,epiretinal membrane,and anterior proliferative vitreoretinopathy.Retinal reattached in 4 cases after silicone oil removal.Conclusions The vitrectomy combined BIOM with ACM is effective and safe for complicated vitreoretinopathy,and clinical results ascertained the practical feasibility of it.

  10. 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.

  11. 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

  12. The Conformal Camera in Modeling Active Binocular Vision

    Directory of Open Access Journals (Sweden)

    Jacek Turski

    2016-08-01

    Full Text Available Primate vision is an active process that constructs a stable internal representation of the 3D world based on 2D sensory inputs that are inherently unstable due to incessant eye movements. We present here a mathematical framework for processing visual information for a biologically-mediated active vision stereo system with asymmetric conformal cameras. This model utilizes the geometric analysis on the Riemann sphere developed in the group-theoretic framework of the conformal camera, thus far only applicable in modeling monocular vision. The asymmetric conformal camera model constructed here includes the fovea’s asymmetric displacement on the retina and the eye’s natural crystalline lens tilt and decentration, as observed in ophthalmological diagnostics. We extend the group-theoretic framework underlying the conformal camera to the stereo system with asymmetric conformal cameras. Our numerical simulation shows that the theoretical horopter curves in this stereo system are conics that well approximate the empirical longitudinal horopters of the primate vision system.

  13. 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

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

    NARCIS (Netherlands)

    Ee, R. van; 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 t

  15. 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

  16. 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...

  17. 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

  18. Binocular vision, the optic chiasm, and their associations with vertebrate motor behavior

    Directory of Open Access Journals (Sweden)

    Matz Lennart Larsson

    2015-07-01

    Full Text Available Ipsilateral retinal projections (IRP in the optic chiasm (OC vary considerably. Most animal groups possess laterally situated eyes and no or few IRP, but, e.g. cats and primates have frontal eyes and high proportions of IRP. The traditional hypothesis that bifocal vision developed to enable predation or to increase perception in restricted light conditions applies mainly to mammals. The eye-forelimb (EF hypothesis presented here suggests that the reception of visual feedback of limb movements in the limb steering cerebral hemisphere was the fundamental mechanism behind the OC evolution. In other words, that evolutionary change in the OC was necessary to preserve hemispheric autonomy. In the majority of vertebrates, motor processing, tactile, proprioceptive, and visual information involved in steering the hand (limb, paw, fin is primarily received only in the contralateral hemisphere, while multisensory information from the ipsilateral limb is minimal. Since the involved motor nuclei, somatosensory areas, and vision neurons are situated in same hemisphere, the neuronal pathways involved will be relatively short, optimizing the size of the brain. That would not have been possible without, evolutionary modifications of IRP. Multiple axon-guidance genes, which determine whether axons will cross the midline or not, have shaped the OC anatomy. Evolutionary change in the OC seems to be key to preserving hemispheric autonomy when the body and eye evolve to fit new ecological niches. The EF hypothesis may explain the low proportion of IRP in birds, reptiles, and most fishes; the relatively high proportions of IRP in limbless vertebrates; high proportions of IRP in arboreal, in contrast to ground-dwelling, marsupials; the lack of IRP in dolphins; abundant IRP in primates and most predatory mammals, and why IRP emanate exclusively from the temporal retina. The EF hypothesis seams applicable to vertebrates in general and hence more parsimonious than traditional hypotheses.

  19. 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

  20. 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.

  1. Binocular Misalignments Elicited by Altered Gravity Provide Evidence for Nonlinear Central Compensation

    Directory of Open Access Journals (Sweden)

    Kara H. Beaton

    2015-06-01

    Full Text Available Increased ocular positioning misalignments upon exposure to altered gravity levels (g-levels have been strongly correlated with space motion sickness severity, possibly due to underlying otolith asymmetries uncompensated in novel gravitational environments. We investigated vertical and torsional ocular positioning misalignments elicited by the 0g and 1.8g g-levels of parabolic flight and used these data to develop a computational model to describe how such misalignments might arise. Ocular misalignments were inferred through two perceptual nulling tasks: Vertical Alignment Nulling (VAN and Torsional Alignment Nulling (TAN. All test subjects exhibited significant differences in ocular misalignments in the novel g-levels, which we postulate to be the result of healthy individuals with 1g-tuned central compensatory mechanisms unadapted to the parabolic flight environment. Furthermore, the magnitude and direction of ocular misalignments in hypo-g and hyper-g, in comparison to 1g, were nonlinear and nonmonotonic. Previous linear models of central compensation do not predict this. Here we show that a single model of the form a+bg^ε, where a, b, and ε are the model parameters and g is the current g-level, accounts for both the vertical and torsional ocular misalignment data observed inflight. Furthering our understanding of oculomotor control is critical for the development of interventions that promote adaptation in spaceflight (e.g., countermeasures for novel g-level exposure and terrestrial (e.g., rehabilitation protocols for vestibular pathology environments.

  2. The Casual Sky Observer's Guide Stargazing with Binoculars and Small Telescopes

    CERN Document Server

    De Laet, Rony

    2012-01-01

    Here is an invaluable guide for those stargazers who are just starting out on their fascinating journey. Don't know what sights to look for? How to locate them? What seasons are best for viewing what stars? All that and more is included in these pages. Plus lots of tips for what equipment to use and good observing techniques. Take this with you to your viewing site, along with your equipment, and you're ready to begin. The universe is there for your viewing pleasure. Enjoy!

  3. 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.

  4. Influence of surface attitude and curvature scaling on discrimination of binocularly presented curved surfaces

    NARCIS (Netherlands)

    Vries, Sjoerd C. de; Kappers, A.M.L.; Koenderink, J.J.

    1994-01-01

    We report on the ability of human observers to discriminate local second-order shape of quadratic stereo-defined surfaces. Local second-order shape can be specified by two parameters: the curvedness (a scale-dependent quantity describing overall curvature of a shape) and the shape index (a scale-ind

  5. A Flexile and High Precision Calibration Method for Binocular Structured Light Scanning System

    Directory of Open Access Journals (Sweden)

    Jianying Yuan

    2014-01-01

    Full Text Available 3D (three-dimensional structured light scanning system is widely used in the field of reverse engineering, quality inspection, and so forth. Camera calibration is the key for scanning precision. Currently, 2D (two-dimensional or 3D fine processed calibration reference object is usually applied for high calibration precision, which is difficult to operate and the cost is high. In this paper, a novel calibration method is proposed with a scale bar and some artificial coded targets placed randomly in the measuring volume. The principle of the proposed method is based on hierarchical self-calibration and bundle adjustment. We get initial intrinsic parameters from images. Initial extrinsic parameters in projective space are estimated with the method of factorization and then upgraded to Euclidean space with orthogonality of rotation matrix and rank 3 of the absolute quadric as constraint. Last, all camera parameters are refined through bundle adjustment. Real experiments show that the proposed method is robust, and has the same precision level as the result using delicate artificial reference object, but the hardware cost is very low compared with the current calibration method used in 3D structured light scanning system.

  6. Binocular Perception of 2D Lateral Motion and Guidance of Coordinated Motor Behavior.

    Science.gov (United States)

    Fath, Aaron J; Snapp-Childs, Winona; Kountouriotis, Georgios K; Bingham, Geoffrey P

    2016-04-01

    Zannoli, Cass, Alais, and Mamassian (2012) found greater audiovisual lag between a tone and disparity-defined stimuli moving laterally (90-170 ms) than for disparity-defined stimuli moving in depth or luminance-defined stimuli moving laterally or in depth (50-60 ms). We tested if this increased lag presents an impediment to visually guided coordination with laterally moving objects. Participants used a joystick to move a virtual object in several constant relative phases with a laterally oscillating stimulus. Both the participant-controlled object and the target object were presented using a disparity-defined display that yielded information through changes in disparity over time (CDOT) or using a luminance-defined display that additionally provided information through monocular motion and interocular velocity differences (IOVD). Performance was comparable for both disparity-defined and luminance-defined displays in all relative phases. This suggests that, despite lag, perception of lateral motion through CDOT is generally sufficient to guide coordinated motor behavior.

  7. 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.

  8. 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

  9. An improved collimation algorithm for the Large Binocular Telescope using source extractor and an on-the-fly reconstructor

    Science.gov (United States)

    Miller, Douglas L.; Rakich, Andrew; Leibold, Torsten

    2012-09-01

    A recent upgrade of the LBTO’s Wavefront Reconstruction algorithm in the Active Optics system has proven to reduce the collimation time by a substantial amount and to provide a much more stable telescope collimation as observing conditions change. The new reconstruction algorithm uses Source Extractor to detect the spots in a Shack-Hartmann wavefront sensor camera image. With information about which Shack spots are detected, a reconstructor matrix is calculated on-the-fly that only includes the illuminated sub-apertures. This drastically improves the wavefront reconstruction for a highly aberrated wavefront when many sub-apertures contain no information. This is generally the situation at the beginning of the night when the collimation of the telescope is set only from models rather than on-sky information and occasionally when a new observational target is acquired. Similarly, the undersized tertiary mirror can cause vignetting of the pupil seen by the Shack-Hartmann wavefront sensor for far off-axis guide stars and again some sub-apertures have no wavefront information. We will present a brief description of the Active Optics system used at the Gregorian focal stations at the LBTO, discuss the original wavefront reconstruction algorithm, describe the new Source Extractor algorithm and compare the performance of these two approaches in several conditions (low signal to noise, highly aberrated wavefront, vignetted pupil, poor seeing).

  10. Visión Binocular en operados de esotropía congénita. Resultados.

    Directory of Open Access Journals (Sweden)

    Teresita de Jesus Mendez Sanchez

    2012-09-01

    Full Text Available Objetivo: Describir los resultados quirúrgicos y la obtención de fusión y estereopsia en operados de esotropía congénita y su relación con la edad quirúrgica.Método: Estudio de serie de casos, en pacientes operados de esotropía congénita en el servicio de Oftalmología Pediátrica del Instituto Cubano de Oftalmología “Ramón Pando Ferrer”, en el período comprendido de enero del  2007 a mayo del 2010. Se analizaron las siguientes variables ángulo de desviación preoperatorio, alineamiento ocular postoperatorio, estabilidad del alineamiento ocular, edad quirúrgica, fusión y  estereopsia.Resultados: En el 96% de los casos se logró ortotropía o alineamiento estéticamente aceptable a las ocho semanas del post operatorio y al año de la cirugía el 73 % mantuvo este alineamiento. El 57,7 % de los pacientes alcanzó fusión y el 30,8 % logró estereopsia, en un rango de 3000 a 400”. Los niños operados después de los 18 meses tuvieron un riesgo cinco veces mayor de no desarrollar fusión y  cuatro veces mayor de no desarrollar estereopsia  que los operados antes de esa edad.Conclusiones: La cirugía temprana resulta importante para mejorar los resultados funcionales visuales en los operados de esotropía congénita.

  11. 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

  12. 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...

  13. Reversible binocular visual loss in temporal association with artesunate-amodiaquine treatment in a child on mefloquine chemoprophylaxis.

    Science.gov (United States)

    Adjei, G O; Adabayeri, V M; Annobil, S H

    2012-09-01

    A case of an acute reversible visual loss in a 10-year-old child who was on mefloquine prophylaxis, and was treated with artesunate-amodiaquine for an acute febrile illness diagnosed clinically as uncomplicated malaria, is reported. On admission the patient could not perceive light and had bilateral papilloedema. She was treated with dexamethasone and recovered her sight gradually over a 21-day period. There has been no previous report to our knowledge, of an association between acute visual loss and mefloquine, amodiaquine, or artesunate in the published literature, even though mefloquine is associated with blurring of vision, and antimalarials of the quinoline class have been associated with retinopathy (during long term use). While causality is difficult to ascribe in this case, it may be prudent to avoid the use of quinoline-based antimalarials for treating acute malaria in travelers taking mefloquine prophylaxis, because information on the safety of concurrent use of artemisinin combination therapies and mefloquine, or other recommended prophylactic regimens, is limited.

  14. Large Binocular Telescope and Sptizer Spectroscopy of Star-forming Galaxies at 1 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 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 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.

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

    Directory of Open Access Journals (Sweden)

    Marie-Eve Laramée

    Full Text Available 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.

  16. Dense range map reconstruction from a versatile robotic sensor system with an active trinocular vision and a passive binocular vision.

    Science.gov (United States)

    Kim, Min Young; Lee, Hyunkee; Cho, Hyungsuck

    2008-04-10

    One major research issue associated with 3D perception by robotic systems is the creation of efficient sensor systems that can generate dense range maps reliably. A visual sensor system for robotic applications is developed that is inherently equipped with two types of sensor, an active trinocular vision and a passive stereo vision. Unlike in conventional active vision systems that use a large number of images with variations of projected patterns for dense range map acquisition or from conventional passive vision systems that work well on specific environments with sufficient feature information, a cooperative bidirectional sensor fusion method for this visual sensor system enables us to acquire a reliable dense range map using active and passive information simultaneously. The fusion algorithms are composed of two parts, one in which the passive stereo vision helps active vision and the other in which the active trinocular vision helps the passive one. The first part matches the laser patterns in stereo laser images with the help of intensity images; the second part utilizes an information fusion technique using the dynamic programming method in which image regions between laser patterns are matched pixel-by-pixel with help of the fusion results obtained in the first part. To determine how the proposed sensor system and fusion algorithms can work in real applications, the sensor system is implemented on a robotic system, and the proposed algorithms are applied. A series of experimental tests is performed for a variety of configurations of robot and environments. The performance of the sensor system is discussed in detail.

  17. 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.

  18. Stereoscopic depth of field: why we can easily perceive and distinguish the depth of neighboring objects under binocular condition than monocular

    Science.gov (United States)

    Lee, Kwang-Hoon; Park, Min-Chul

    2016-06-01

    In this paper, we introduce a high efficient and practical disparity estimation using hierarchical bilateral filtering for realtime view synthesis. The proposed method is based on hierarchical stereo matching with hardware-efficient bilateral filtering. Hardware-efficient bilateral filtering is different from the exact bilateral filter. The purpose of the method is to design an edge-preserving filter that can be efficiently parallelized on hardware. The proposed hierarchical bilateral filtering based disparity estimation is essentially a coarse-to-fine use of stereo matching with bilateral filtering. It works as follows: firstly, the hierarchical image pyramid are constructed; the multi-scale algorithm then starts by applying a local stereo matching to the downsampled images at the coarsest level of the hierarchy. After the local stereo matching, the estimated disparity map is refined with the bilateral filtering. And then the refined disparity map will be adaptively upsampled to the next finer level. The upsampled disparity map used as a prior of the corresponding local stereo matching at the next level, and filtered and so on. The method we propose is essentially a combination of hierarchical stereo matching and hardware-efficient bilateral filtering. As a result, visual comparison using real-world stereoscopic video clips shows that the method gives better results than one of state-of-art methods in terms of robustness and computation time.

  19. 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...

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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...

  5. 三维视觉测量技术中的双目纹理映射技术%3D Texture Mapping Technique Based on Binocular System in Vision Metrology

    Institute of Scientific and Technical Information of China (English)

    张效栋; 孙长库

    2008-01-01

    设计了基于双目摄像机的三维纹理映射系统,单色和彩色摄像机分别负责三维坐标和颜色信息的采集;建立了双目摄像机的像素匹配模型,并设计了简单的标定方法,确定模型中的内部和结构参数,建立高精度的像素对应关系,配合实现三维数据的纹理映射.还对双目纹理映射方法的测量过程进行了详细描述.经过实验验证,该方法不仅简单易用,还具有高于0.1个像素的匹配精度.

  6. 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.

  7. 随机点立体图视差信息加工的事件相关电位研究%An Event-related Potential Study the on Information Processing of Binocular Disparity in Random-dot Stereogram

    Institute of Scientific and Technical Information of China (English)

    沈模卫; 王锐; 唐孝威; 朱海燕

    2004-01-01

    目的研究以随机点立体图(Random-dot stereogram, RDS)产生的精细立体视觉的非连续-连续视差梯度类型、非交叉-交叉视差交叉类型和大-小视差对ERP的影响.方法采用16名(8男,8女)深度知觉正常的被试,以红绿眼镜产生立体视觉,记录其行为及脑电数据.结果 1)非连续视差梯度的反应正确率高于连续视差梯度;大视差条件的反应正确率高于小视差条件.2)非连续视差梯度较连续视差梯度诱发的N160潜伏期更短,N350的波幅更大;与非交叉视差相比,交叉视差的N350潜伏期较短;大视差比小视差具有更短的N160潜伏期和更大的P280波幅.结论不同视差梯度显著影响视差信息的加工,非连续视差梯度具有一定的加工优势;N160的潜伏期和P280的波幅与视差大小加工相关;N350成分还与视差交叉信息的加工相关.

  8. 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.

  9. Binocular clinical comparison study of Tecnis multifocal aspheric and monofocal spherical intraocular lenses%双眼植入Tecnis多焦点和单焦点球面人工晶状体的临床比较研究

    Institute of Scientific and Technical Information of China (English)

    叶盼盼; 姚克; 李霞; 吴炜; 黄晓丹; 俞一波

    2010-01-01

    目的 比较双眼植入Tecnis多焦点人工晶状体(IOL)与传统球面单焦点IOL对视觉功能的影响.方法 前瞻性临床研究.对100例(200只眼)患者实施超声乳化白内障吸除联合IOL植入术,采用随机数字表法随机植入前表面非球面和后表面衍射环的多焦点IOL(美国AMO公司Tecnis ZM900型;多焦点非球面组)与传统球面单焦点IOL(美国Bausch&Lomb公司Akreos Adapt型;单焦点球面组).随访3个月,检测两组IOL眼的5 m、1 m、63 cm、40 cm和30 cm各距离的裸眼视力和最佳远视力矫正下的近视力、调节幅度、全眼球差、对比敏感度、眩光敏感度以及近立体视锐度,并进行患者视功能和满意度问卷调查.对计量资料中两组数据进行正态性检验分析,满足正态分布的行t检验,不满足的行Mann-Whitney U检验,对计数资料行x2检验.结果 随访3个月后观察发现,30 cm和40cm距离多焦点非球面组的双眼远视力矫正下视力(logMAR视力)为0.24±0.12和0.22±0.11,明显优于单焦点球面组(Z=-8.261,P=0.000;Z=-5.508,P=0.000),其余各距离无明显差异;较之单焦点球面组,多焦点非球面组患者提高2.3~2.8 D的调节幅度(单眼Z=-10.655,P=0.000;双眼Z=-2.709,P=0.007);无论5 mm或3 mm瞳孔直径时多焦点非球面组的全眼球差[(0.027±0.160)μm,(0.006±0.083)μm]均小于单焦点球面组[(0.269±0.161)μm,(0.037±0.205)μm](Z=-8.815,P=0.000,Z=-2.791,P=0.005);两组的对比敏感度无明显差别,但单焦点球面组的眩光敏感度明显高于多焦点非球面组(P=0.0000);多焦点非球面组的裸眼近立体视锐度为(72.4±29.9)",优于单焦点球面组的(92.8±35.7)"(Z=-3.089,P=0.0002),近矫后近立体视锐度两组无统计学差异.结论 Tecnis多焦点非球面IOL较单焦点球面IOL可提供较好的近视力及调节幅度,提高近立体视锐度,非球面设计减少全眼球差,在一定程度上改善对比敏感度.%Purpose To compare visual function in pseudophakic patients with bilateral implantation of Tecnis multifocal aspheric and conventional monofocal spherical intraocular lenses (IOL). Methods A prospective study of 100 consecutive cases (200 eyes) was conducted. All cataract patients underwent phaocoemulsification were randomized to receive multifocal aspheric IOL ( Tecnis ZM900, AMO, multifocal aspheric group) or conventional spherical IOL ( Akreos Adapt, Bausch&Lomb, monofocal spherical group) . The following investigations were performed to assess the uncorrected and distance-corrected visual acuity of distance, intermediate and near distances, accommodative amplitude, spherical aberrations of total eye, contrast sensitivity, glare sensitivity and near stereoacuity. Patients were surveyed for visual disturbances and lifestyle visual quality. The independent-samples t test waa used to compare the measure data which met normal distribution and the Mann-Whitney U test was used to compare the measure data which didn' t meet. The chi-square test was applied to compare categorical variables. Results The uncorrected and distance-corrected bilateral visual acuity of multifocal aspheric group at 30 cm and 40 cm were 0. 24 ± 0. 12 and 0. 22 ± 0. 11 (logMAR) , better than monofocal spherical group ( Z = - 8. 261, P = 0. 000;Z = -5. 508, P =0.000), but the visual acuity at other distances had no statistical difference between two groups. Patients with multifocal aspheric IOL had significantly higher accommodative amplitude than those with monofcal spherical IOL, improved about 2. 3 - 2. 8 D ( Z= -10. 655, P = 0. 000; Z =- 2. 709, P = 0. 007). Mean spherical aberration of multifocal aspheric group was ( 0. 027 ±0. 160) μm and (0. 006 ±0. 083)μm, significantly lower than that of monofocal spherical group (0. 269 ±0. 161) μm, (0.037 ±0.205) μm at 5 mm and 3 mm pupil diameter(Z= - 8. 815, P = 0. 000; Z = -2. 791, P = 0. 005) . The difference of contrast sensitivity was not significant, but glare sensitivity was higher for monofocal spherical group than for multifocal aspheric group. Multifocal aspheric group

  10. 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 .

  11. 双目视觉下建立动态四轮定位测量平面的方法%Approach to Establishing Dynamic Four-wheel Alignment Measurement Plane With Binocular Vision

    Institute of Scientific and Technical Information of China (English)

    胡潇琨; 毕远伟

    2014-01-01

    Modeling method for vehicle's four-wheel alignment measurement plane is proposed in this paper, with the purpose of overcoming the difficulty of the present measurement for vehicle's four-wheel alignment that was severely affected by the measuring environment. First, by moving vehicles, different image information of the wheel target was obtained during the moving of the vehicle. Second, with the spatial vector method, the measurement plane was dynamically created, and the wheel's axle data were calculated, as a result this method get the four-wheel alignment parameters and solves the problem that the error is too big when measuring level is not even or measurement environment interfere with the result. Moreover, with the new method, the measurement procedure is simplified. Test shows that the four-wheel alignment parameters are not affected by the lifting equipment and site, and the margin of error is between - 0. 05° and 0. 05°.%针对现有车辆四轮定位设备受测量环境影响大等弊端,利用双目立体视觉测量技术,提出了一种车辆四轮定位测量平面的动态建模方法.通过推动车辆,获取多组车辆运动过程中的车轮靶标图像信息,运用空间向量方法,建立动态测量平面,计算车轮旋转轴,求取四轮定位参数,解决因测量现场不水平和测量环境干扰造成的误差偏大等问题,并简化了测量步骤.经过测试,四轮定位参数不受举升设备和场地影响,测量误差在±0.05°范围内.

  12. A New Stereo Matching Algorithm Used in Target Tracking of Binocular Mobile Robot%一种应用于双目移动机器人目标跟踪的新型立体匹配算法

    Institute of Scientific and Technical Information of China (English)

    于乃功; 林佳; 阮晓钢

    2012-01-01

    The accuracy and real - time requirements of stereo matching required by the target tracking of mobile robot, an improvement WTA algorithm based on the parallel configuration system is proposed. Firstly, extract edge points of the image and the relatively big difference points between two images as the feature points. Then, the feature points are implemented the stereo matching using winner-take-all (WTA) algorithm. Non-feature points are only implemented a simple verification, and their disparity values are the ones of neighboring pixel. Finally, a dense disparity map is yield. The feature points extracted by the algorithm focus on the disparity discontinuity regions and experimental results show that the matching accuracy of the algorithm is equivalent to other existing algorithms, the speed of calculation meets the real-time requirements very well and it has the better edge feature. So it is a stereo matching algorithm with accurate matching and good real - time.%针对移动机器人目标跟踪对立体匹配准确性和实时性的要求,提出了一种基于平行配置系统的改进WTA算法;首先提取图像的边缘点和两幅视图间存在较大差异的点作为特征点;然后对特征点采用WTA算法进行立体匹配,而对非特征点仅进行简单的验证,其视差值为邻近像素的视差值;最后得到致密的视差图;该算法提取的特征点集中于视差不连续区域,实验结果表明该算法匹配精度与现有其它算法相当,但计算速度很好地满足了实时性的要求,并且边缘特性较好,是一种匹配准确、实时性好的立体匹配算法.

  13. Nursing care of a case with systemic lupus erythematosus complicated with binocular optic nerve demyelination%1例系统性红斑狼疮并发双眼视神经脱髓鞘病人的护理

    Institute of Scientific and Technical Information of China (English)

    田宇红; 霍士英; 何继东

    2009-01-01

    @@ 系统性红斑狼疮(systemic lupus erythematosus,SLE)是累及全身多系统、多器官的自身免疫性疾病.病程迁延,病情反复发作,临床上主要表现为皮肤、关节和脏器损害,SLE以年轻女性多见,其中育龄妇女占90%~95%.

  14. 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.

  15. 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.

  16. 基于物联网感知层的移动机器人自组织网动态视觉图像建模(英文)

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The dynamic multichannel binocular visual image modeling is studied based on Internet of Things (IoT) Perception Layer, using mobile robot self-organizing network. By employing multigroup mobile robots with binocular visual system, the real visual images of the object will be obtained. Then through the mobile self-organizing network, a three-dimensional model is rebuilt by synthesizing the returned images. On this basis, we formalize a novel algorithm for multichannel binocular visual three-dimensional imag...

  17. System and Device with Three-Dimensional Image Display

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to a binocular device (44) and a system (40) including a binocular device (44) configured for displaying one or more labels for an input device (2), such as a keyboard or a control panel, comprising a plurality of parts (4, 6) configured for activation and registration...... by depression. The binocular device (44) is configured for displaying a label of an activation part (4) as a three-dimensional label at the activation part (4)....

  18. 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...

  19. 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...

  20. 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...

  1. Eccentric gaze direction in patients with central field loss

    NARCIS (Netherlands)

    Verezen, C.A.; Hoyng, C.B.; Meulendijks, C.F.M.; Keunen, J.E.E.; Klevering, B.J.

    2011-01-01

    PURPOSE.: This study describes the binocular eccentric gaze direction (EGD) of 434 patients with binocular central field loss and presents a comparison with other studies on eccentric gaze behavior. METHODS.: We reviewed the records of 434 patients with bilateral central scotomas. Eligible patients

  2. 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

  3. 激光治疗鲜红斑痣手术机器人双目视觉系统的实时立体匹配%REAL-TIME STEREO MATCHING ALGORITHM IN PHOTODYNAMIC THERAPY BINOCULAR SURVEILLANCE SYSTEM FOR PORT WINE STAIN

    Institute of Scientific and Technical Information of China (English)

    唐晓英; 应龙; 刘伟峰

    2010-01-01

    针对激光治疗鲜红斑痣手术机器人双目视觉系统在监测治疗区域的空间位置时立体匹配的实时性和准确性要求,提出了一种基于极线引导的立体匹配算法.采用基于角点的Hu矩匹配,计算双目视觉系统的基本矩阵.实验结果与计算结果相符.

  4. American Academy of Optometry

    Science.gov (United States)

    ... Education Online Past Abstract & Outline Search Past Ocular Photography Contest Winners FAQs Become a Fellow Why Become ... Sections Anterior Segment Become a Diplomate Binocular Vision, Perception and Pediatric Optometry Become a BVPPO Diplomate Cornea, ...

  5. 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

  6. 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.

  7. Magnetoencephalographic Activity Related to Conscious Perception Is Stable within Individuals across Years but Not between Individuals

    DEFF Research Database (Denmark)

    Sandberg, Kristian; Barnes, Gareth Robert; Rees, Geraint;

    2014-01-01

    the generalization across time within individuals and across different individuals. We trained classification algorithms to decode conscious perception from neural activity recorded during binocular rivalry using magnetoencephalography (MEG). The classifiers were then used to predict the perception of the same...

  8. 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...

  9. 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...

  10. 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 ...

  11. 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...

  12. Free Exploration of Painting Uncovers Particularly Loose Yoking of Saccades in Dyslexics

    Science.gov (United States)

    Kapoula, Zoi; Ganem, Rebecca; Poncet, Sarah; Gintautas, Daunys; Eggert, Thomas; Bremond-Gignac, Dominique; Bucci, Maria Pia

    2009-01-01

    Binocular yoking of saccades is essential for single vision of words during reading. This study examines the quality of binocular coordination in individuals with dyslexia, independent of the process of reading. Fifteen dyslexia children (11.2 plus or minus 1.4 years) and 15 non-dyslexia individuals (8 children, aged 11.1 plus or minus 1.3 years,…

  13. Judgments of the distance to nearby virtual objects: interaction of viewing conditions and accommodative demand.

    Science.gov (United States)

    Ellis, S R; Menges, B M

    1997-08-01

    Ten subjects adjusted a real-object probe to match the distance of nearby virtual objects optically presented via a see-through, helmet-mounted display. Monocular, binocular, and stereoscopic viewing conditions were used with two levels of required focus. Observed errors may be related to changes in the subjects' binocular convergence. The results suggest ways in which virtual objects may be presented with improved spatial fidelity.

  14. 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...

  15. Thalamocortical dynamics of the McCollough effect: boundary-surface alignment through perceptual learning.

    Science.gov (United States)

    Grossberg, Stephen; Hwang, Seungwoo; Mingolla, Ennio

    2002-05-01

    This article further develops the FACADE neural model of 3-D vision and figure-ground perception to quantitatively explain properties of the McCollough effect (ME). The model proposes that many ME data result from visual system mechanisms whose primary function is to adaptively align, through learning, boundary and surface representations that are positionally shifted due to the process of binocular fusion. For example, binocular boundary representations are shifted by binocular fusion relative to monocular surface representations, yet the boundaries must become positionally aligned with the surfaces to control binocular surface capture and filling-in. The model also includes perceptual reset mechanisms that use habituative transmitters in opponent processing circuits. Thus the model shows how ME data may arise from a combination of mechanisms that have a clear functional role in biological vision. Simulation results with a single set of parameters quantitatively fit data from 13 experiments that probe the nature of achromatic/chromatic and monocular/binocular interactions during induction of the ME. The model proposes how perceptual learning, opponent processing, and habituation at both monocular and binocular surface representations are involved, including early thalamocortical sites. In particular, it explains the anomalous ME utilizing these multiple processing sites. Alternative models of the ME are also summarized and compared with the present model.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Towards Determination of Visual Requirements for Augmented Reality Displays and Virtual Environments for the Airport Tower

    Science.gov (United States)

    Ellis, Stephen R.

    2006-01-01

    The visual requirements for augmented reality or virtual environments displays that might be used in real or virtual towers are reviewed with respect to similar displays already used in aircraft. As an example of the type of human performance studies needed to determine the useful specifications of augmented reality displays, an optical see-through display was used in an ATC Tower simulation. Three different binocular fields of view (14deg, 28deg, and 47deg) were examined to determine their effect on subjects ability to detect aircraft maneuvering and landing. The results suggest that binocular fields of view much greater than 47deg are unlikely to dramatically improve search performance and that partial binocular overlap is a feasible display technique for augmented reality Tower applications.

  3. 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

  4. Assessment of Cortical Dysfunction in Patients with Intermittent Exotropia: An fMRI Study.

    Science.gov (United States)

    Li, Qian; Bai, Junxing; Zhang, Junran; Gong, Qiyong; Liu, Longqian

    2016-01-01

    Neural imaging studies have found the connection between strabismus and brain cortex. However, the pathological mechanisms of intermittent exotropia are still not fully understood. In the present study, changes of binocular fusion related cortices in intermittent exotropia were investigated with blood oxygen level dependent functional magnetic resonance imaging. Activated cortices induced by fusion stimulus were found to be distributed in several regions such as bilateral middle occipital gyrus, bilateral middle temporal gyrus, left superior parietal lobule and so on. Compared with normal subjects, the increased activation intensity was observed in bilateral superior parietal lobule and inferior parietal lobule in subjects with intermittent exotropia. These findings indicate that binocular fusion involves a complicated brain network including several regions. And cortical activities of bilateral superior parietal lobule and inferior parietal lobule compensate for the binocular fusion dysfunction in intermittent exotropia. PMID:27501391

  5. What is Stereopsis?

    Directory of Open Access Journals (Sweden)

    D Vishwanath

    2012-07-01

    Full Text Available “Stereopsis” refers to the characteristically vivid qualitative impression of 3D structure that is observed when real (or simulated-3D scenes are viewed binocularly. Stereopsis is associated with a compelling perception of solidity or 3-dimensionality, a clear sense of space between objects, and a phenomenal sense of realism. These visual characteristics are conventionally thought to be a result of the different views of an object afforded by binocular vision (disparity or self-motion (motion parallax. However, such visual characteristics can also be obtained under controlled monocular viewing of pictures. One explanation for the impression of monocular stereopsis is based on the notion of cue-coherence/conflict (eg, Ames, 1925. When a picture is viewed with both eyes, binocular cues specify the flat picture surface and are in conflict with the 3-dimentionality implied by the pictorial cues. The elimination of these conflicting cues under monocular viewing putatively causes the enhancement of pictorial depth impression. The cue-coherence/conflict explanation also predicts a greater magnitude of perceived depth relief accompanying the greater impression of stereopsis. I will present an alternative theory that stereopsis is the conscious perception of the precision of the brains estimate of absolute (egocentrically scaled depth. Both qualitative and quantitative empirical results are consistent with this theory. Specifically, they show that (i the same qualitative characteristics of depth impression are reported under binocular viewing of real scenes, stereoscopic images, and controlled monocular viewing of pictures; (ii the impression of stereopsis is measurable and its variation, under different viewing conditions is not consistent with a cue-conflict account; (iii stereopsis can be elicited by manipulating egocentric distance cues when viewing pictures, without altering conflicting binocular cues; and (iv under conditions that elicit

  6. Visual Field Testing with Head-Mounted Perimeter ‘imo’

    Science.gov (United States)

    Matsumoto, Chota; Yamao, Sayaka; Nomoto, Hiroki; Takada, Sonoko; Okuyama, Sachiko; Kimura, Shinji; Yamanaka, Kenzo; Aihara, Makoto; Shimomura, Yoshikazu

    2016-01-01

    Purpose We developed a new portable head-mounted perimeter, “imo”, which performs visual field (VF) testing under flexible conditions without a dark room. Besides the monocular eye test, imo can present a test target randomly to either eye without occlusion (a binocular random single eye test). The performance of imo was evaluated. Methods Using full HD transmissive LCD and high intensity LED backlights, imo can display a test target under the same test conditions as the Humphrey Field Analyzer (HFA). The monocular and binocular random single eye tests by imo and the HFA test were performed on 40 eyes of 20 subjects with glaucoma. VF sensitivity results by the monocular and binocular random single eye tests were compared, and these test results were further compared to those by the HFA. The subjects were asked whether they noticed which eye was being tested during the test. Results The mean sensitivity (MS) obtained with the HFA highly correlated with the MS by the imo monocular test (R: r = 0.96, L: r = 0.94, P < 0.001) and the binocular random single eye test (R: r = 0.97, L: r = 0.98, P < 0.001). The MS values by the monocular and binocular random single eye tests also highly correlated (R: r = 0.96, L: r = 0.95, P < 0.001). No subject could detect which eye was being tested during the examination. Conclusions The perimeter imo can obtain VF sensitivity highly compatible to that by the standard automated perimeter. The binocular random single eye test provides a non-occlusion test condition without the examinee being aware of the tested eye. PMID:27564382

  7. 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.

  8. 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.

  9. Counter sniper: a localization system based on dual thermal imager

    Science.gov (United States)

    He, Yuqing; Liu, Feihu; Wu, Zheng; Jin, Weiqi; Du, Benfang

    2010-11-01

    Sniper tactics is widely used in modern warfare, which puts forward the urgent requirement of counter sniper detection devices. This paper proposed the anti-sniper detection system based on a dual-thermal imaging system. Combining the infrared characteristics of the muzzle flash and bullet trajectory of binocular infrared images obtained by the dual-infrared imaging system, the exact location of the sniper was analyzed and calculated. This paper mainly focuses on the system design method, which includes the structure and parameter selection. It also analyzes the exact location calculation method based on the binocular stereo vision and image analysis, and give the fusion result as the sniper's position.

  10. Does monocular visual space contain planes?

    NARCIS (Netherlands)

    Koenderink, J.J.; Albertazzi, L.; Doorn, A.J. van; Ee, R. van; Grind, W.A. van de; Kappers, A.M.L.; Lappin, J.S.; Norman, J.F.; Oomes, A.H.J.; Pas, S.F. te; Phillips, F.; Pont, S.C.; Richards, W.A.; Todd, J.T.; Verstraten, F.A.J.; Vries, S.C. de

    2010-01-01

    The issue of the existence of planes—understood as the carriers of a nexus of straight lines—in the monocular visual space of a stationary human observer has never been addressed. The most recent empirical data apply to binocular visual space and date from the 1960s (Foley, 1964). This appears to be

  11. 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.

  12. 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.

  13. [Adaptation of Goldmann's cupula to the detection of subjective cyclodiplopia. Preliminary study].

    Science.gov (United States)

    George, J L; Oliveiri, D; Bastien, M; Cordonnier, M O; Richard, M; Raspiller, A

    1990-01-01

    Although the single binocular visual field provides an indication of the area free of horizontal or vertical diplopia, it does not assess cyclorotary diplopia. A cylindric glass is adapted on the Goldmann perimeter and gives a linear spot, allowing the determination of the cyclorotary component of diplopia.

  14. 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…

  15. The LEECH Exoplanet Imaging Survey: Orbit and Component Masses of the Intermediate-Age, Late-Type Binary NO UMa

    Science.gov (United States)

    Schlieder, Joshua E.; Skemer, Andrew J.; Maire, Anne-Lise; Desidera, Silvano; Hinz, Philip; Skrutskie, Michael F.; Leisenring, Jarron; Bailey, Vanessa; Defrère, Denis; Esposito, Simone; Strassmeier, Klaus G.; Weber, Michael; Biller, Beth A.; Bonnefoy, Mickaël; Buenzli, Esther; Close, Laird M.; Crepp, Justin R.; Eisner, Josh A.; Hofmann, Karl-Heinz; Henning, Thomas; Morzinski, Katie M.; Schertl, Dieter; Weigelt, Gerd; Woodward, Charles E.

    2016-02-01

    We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBT Interferometer Exozodi Exoplanet Common Hunt exoplanet imaging survey. Our H-, Ks-, and L‧-band observations resolve the system at angular separations Tenerife, an AIP facility jointly operated by AIP and IAC.

  16. 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.

  17. 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.

  18. 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…

  19. 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.

  20. 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

  1. 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.

  2. Resources for Teaching Astronomy.

    Science.gov (United States)

    Grafton, Teresa; Suggett, Martin

    1991-01-01

    Resources that are available for teachers presenting astronomy in the National Curriculum are listed. Included are societies and organizations, resource centers and places to visit, planetaria, telescopes and binoculars, planispheres, star charts, night sky diaries, equipment, audiovisual materials, computer software, books, and magazines. (KR)

  3. 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.

  4. 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

  5. Context compensation in the vestibulo-ocular reflex during active head rotations

    NARCIS (Netherlands)

    Medendorp, W.P.; Gisbergen, J.A.M. van; Pelt, S. van; Gielen, C.C.A.M.

    2000-01-01

    The vestibuloocular reflex (VOR) needs to modulate its gain depending on target distance to prevent retinal slip during head movements. We investigated gain modulation (context compensation) for binocular gaze stabilization in human subjects during voluntary yaw and pitch head rotations. Movements o

  6. 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…

  7. CIV Line-Width Anomalies

    DEFF Research Database (Denmark)

    Denney, Kelly D.; Pogge, Richard W.; Assef, Roberto J.;

    2013-01-01

    Comparison of six high-redshift quasar spectra obtained with the Large Binocular Telescope with previous observations from the Sloan Digital Sky Survey shows that failure to correctly identify absorption and other problems with accurate characterization of the CIV emission line profile in low S...

  8. 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.

  9. Interocular transfer of adaptation in the primary visual cortex.

    Science.gov (United States)

    Howarth, Christopher M; Vorobyov, Vasily; Sengpiel, Frank

    2009-08-01

    Prolonged viewing of an unchanging pattern causes adaptation, which can be demonstrated by visual aftereffects such as the tilt and waterfall illusions. In normal observers, these typically exhibit interocular transfer (IOT), being observed when the adapting and test stimuli are shown to different eyes. Convergence of inputs from both eyes upon binocular neurons only occurs in the primary visual cortex (V1), and adaptation is substantially a cortical phenomenon. However, little is known about a physiological substrate of IOT in V1 and how it relates to the binocularity of neurons and local ocular dominance (OD) column architecture. We employed optical imaging to obtain OD maps in cat V1 and recorded from single neurons at targeted penetration sites to quantify their adaptation by drifting gratings when adapter and test stimulus were presented either to the same or to the opposite eyes. In contrast to earlier reports, clear IOT of adaptation was observed for binocular as well as monocular neurons; at population level, its strength amounted to 55%. Moreover, the position of the cells with respect to OD column borders had no significant effect on the strength of IOT. IOT does not appear to strongly depend on conventional binocularity of neurons.

  10. Investigating eye movement acquisition and analysis technologies as a causal factor in differential prevalence of crossed and uncrossed fixation disparity during reading and dot scanning.

    Science.gov (United States)

    Kirkby, J A; Blythe, H I; Drieghe, D; Benson, V; Liversedge, S P

    2013-09-01

    Previous studies examining binocular coordination during reading have reported conflicting results in terms of the nature of disparity (e.g. Kliegl, Nuthmann, & Engbert (Journal of Experimental Psychology General 135:12-35, 2006); Liversedge, White, Findlay, & Rayner (Vision Research 46:2363-2374, 2006). One potential cause of this inconsistency is differences in acquisition devices and associated analysis technologies. We tested this by directly comparing binocular eye movement recordings made using SR Research EyeLink 1000 and the Fourward Technologies Inc. DPI binocular eye-tracking systems. Participants read sentences or scanned horizontal rows of dot strings; for each participant, half the data were recorded with the EyeLink, and the other half with the DPIs. The viewing conditions in both testing laboratories were set to be very similar. Monocular calibrations were used. The majority of fixations recorded using either system were aligned, although data from the EyeLink system showed greater disparity magnitudes. Critically, for unaligned fixations, the data from both systems showed a majority of uncrossed fixations. These results suggest that variability in previous reports of binocular fixation alignment is attributable to the specific viewing conditions associated with a particular experiment (variables such as luminance and viewing distance), rather than acquisition and analysis software and hardware.

  11. Reading and visual search: a developmental study in normal children.

    Science.gov (United States)

    Seassau, Magali; Bucci, Maria-Pia

    2013-01-01

    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.

  12. 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.

  13. 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

  14. History of falling and visual ability among independently living elderly in Sweden

    Directory of Open Access Journals (Sweden)

    Källstrand-Eriksson J

    2016-07-01

    Full Text Available Jeanette Källstrand-Eriksson,1 Cathrine Hildingh,1 Boel Bengtsson2 1School of Health and Welfare, Halmstad University, Halmstad, 2Department of Clinical Sciences in Malmö, Ophthalmology, Lund University, Malmö, Sweden Purpose: The aim of this study was to assess the performance-based visual ability among independently living elderly subjects and to investigate whether there was any association between visual ability and falls.Subjects and methods: A total of 298 randomly selected subjects aged 70–85 years were invited for an examination including monocular and binocular visual acuity (VA, contrast sensitivity (CS, stereoscopic vision, and monocular visual fields (VFs, which were integrated to estimate the binocular VFs. Type of lenses used in their habitual correction was noted.Results: Out of the 212 subjects who were examined, 38% reported at least one fall and 48% of these reported at least two falls during the last 2 years. Most subjects had normal results; 90% had normal binocular VA, 85% had normal binocular CS, and ~80% had positive stereopsis. Twenty-nine subjects had VF defects in the lower quadrants of the binocular VF, and 14 of these reported at least one fall. A significant association was seen between one fall or more and VA better eye, the odds ratio (OR was 2.26, P=0.013, and between recurrent falls and lack of stereoscopic vision, the OR was 3.23, P=0.002; no other functional test showed any significant association with recurrent falls. The ORs were 1.58 for worse binocular VA, 0.60 for worse binocular CS, and 0.71 for non-normal stereoscopic vision for at least one fall, but wide confidence intervals made it difficult to draw firm conclusions about any association. Bifocal or progressive spectacles were worn by 71% with no significant difference between fallers and nonfallers (P=0.078.Conclusion: Even though ~40% of the total sample had experienced one or more falls, the only visual function test significantly associated

  15. 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

  16. 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.

  17. 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

  18. 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

  19. [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

  20. SPATIALLY RESOLVED M-BAND EMISSION FROM IO’S LOKI PATERA–FIZEAU IMAGING AT THE 22.8 m LBT

    Energy Technology Data Exchange (ETDEWEB)

    Conrad, Albert; Veillet, Christian [LBT Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Kleer, Katherine de; Pater, Imke de [University of California at Berkeley, Berkeley, CA 94720 (United States); Leisenring, Jarron; Defrère, Denis; Hinz, Philip; Skemer, Andy [University of Arizona, 1428 E. University Blvd., Tucson, AZ 85721 (United States); Camera, Andrea La; Bertero, Mario; Boccacci, Patrizia [DIBRIS, University of Genoa, Via Dodecaneso 35, I-16146 Genova (Italy); Arcidiacono, Carmelo [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Hofmann, Karl-Heinz; Schertl, Dieter; Weigelt, Gerd [Max Planck Institute for Radio Astronomy, Auf dem Hügel 69, D-53121 Bonn (Germany); Kürster, Martin [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Rathbun, Julie [Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719 (United States); Skrutskie, Michael [University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Spencer, John [Southwest Research Institute, 1050 Walnut Ste. Suite 300, Boulder, CO 80302 (United States); Woodward, Charles E., E-mail: aconrad@lbto.org [Minnesota Institute for Astrophysics, 116 Church St., Minneapolis, MN 55455 (United States)

    2015-05-15

    The Large Binocular Telescope Interferometer mid-infrared camera, LMIRcam, imaged Io on the night of 2013 December 24 UT and detected strong M-band (4.8 μm) thermal emission arising from Loki Patera. The 22.8 m baseline of the Large Binocular Telescope provides an angular resolution of ∼32 mas (∼100 km at Io) resolving the Loki Patera emission into two distinct maxima originating from different regions within Loki’s horseshoe lava lake. This observation is consistent with the presence of a high-temperature source observed in previous studies combined with an independent peak arising from cooling crust from recent resurfacing. The deconvolved images also reveal 15 other emission sites on the visible hemisphere of Io including two previously unidentified hot spots.

  1. Objects of Desire: A Reading of the Reward System in World of Warcraft

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel

    2012-01-01

    This article is written in an attempt to navigate the reward structure in World of Warcraft (WoW). Alongside its analysis of the reward structure in WoW, this article draws upon the paradoxical design of desire itself. In doing so, it takes a binocular perspective that addresses both the interpla......W, where the level cap was 60 and the guild raids in the high-end instances demanded the participation of 40 players. The scene is intended to provide the reader with insights both of the reward structure of WoW and of player's experience of the game world.......This article is written in an attempt to navigate the reward structure in World of Warcraft (WoW). Alongside its analysis of the reward structure in WoW, this article draws upon the paradoxical design of desire itself. In doing so, it takes a binocular perspective that addresses both the interplay...

  2. 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.

  3. 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

  4. The scintillating grid illusion in stereo-depth.

    Science.gov (United States)

    Schrauf, M; Spillmann, L

    2000-01-01

    The dark scintillating dots occurring on a gray-on-black, modified Hermann grid [Schrauf, M., Lingelbach, B., & Wist, E. R. (1997). The scintillating grid illusion. Vision Research, 37, 1033-1038] were studied in stereo-depth by assigning various degrees of disparity to the white inducing disks. Dependent on the sign of disparity, the disks and the dark illusory spots within them appeared to lie either in the same plane, in front of, or behind the grid. At zero disparity, illusory strength was maximum and was the same for stereo, binocular and monocular viewing. With increasing disparity, the illusion became progressively weaker; however, the decrease for stereo-patterns was significantly less than for control patterns presented binocularly or monocularly. These results suggest a central contribution to the scintillation effect.

  5. Endoscopic laser treatment of subglottic and tracheal stenosis

    Science.gov (United States)

    Correa, Alex J.; Garrett, C. Gaelyn; Reinisch, Lou

    1999-06-01

    The ideal laser produces discrete wounds in a reproducible manner. The CO2 laser with its 10.6 micron wavelength is highly absorbed by water, its energy concentrated at the point of impact and the longer wavelength creates less scatter in tissue. The development of binocular endoscopic delivery system for use with binocular microlaryngoscopes have aided in using CO2 laser to treat patients with subglottic and tracheal stenosis. Often, patients with these disease processes require multiple endoscopic or open reconstructive procedures and my ultimately become tracheotomy dependent. The canine model of subglottic stenosis that has been develop allows testing of new agents as adjuncts to laser treatment. Mitomycin-C is an antibiotic with antitumor activity used in chemotherapy and also in ophthalmologic surgery due to its known inhibition of fibroblast proliferation. Current studies indicate this drug to have significant potential for improving our current management of this disease process.

  6. 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!

  7. 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)

  8. 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...

  9. VizieR Online Data Catalog: U-band photometry of 17 WINGS clusters (Omizzolo+, 2014)

    Science.gov (United States)

    Omizzolo, A.; Fasano, G.; Reverte Paya, D.; de Santis, C.; Grado, A.; Bettoni, D.; Poggianti, B.; D'Onofrio, M.; Moretti, A.; Varela, J.; Fritz, J.; Gullieuszik, M.; Cava, A.; Grazian, A.; Moles, M.

    2014-01-01

    The observations were made with three different wide-field cameras: - the 90prime camera at the 90inches (2.3m) BOK telescope (90prime@BOK, Kitt Peak), in 2 runs: 2000-06-20/22 and 2006-11-22/23 - the Wide Field Camera at the 2.5m Isaac Newton Telescope (WFC@INT), in 1 run: 2005-05-10/14 - the Large Binocular Camera at the Large Binocular Telescope (LBC@LBT). on the 5 nights 2007-03-12, 2007-05-19, 2008-06-04, 2008-06-07 and 2008-06-08 - For one cluster (Abell 970) we used imaging data from the WFI@MPG (ESO2.2 archive), performed on 2000-02-27/29 All clusters have been imaged in the U-band, and many clusters have also been imaged in the optical (B,V) bands. (22 data files).

  10. 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...

  11. 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 ...

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. 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...

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. Metamorphopsia assessment before and after vitrectomy for macular hole

    DEFF Research Database (Denmark)

    Krøyer, Kristian; Christensen, Ulrik; la Cour, Morten;

    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...... 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.)....

  4. Negative Body Image Associated with Changes in the Visual Body Appearance Increases Pain Perception

    OpenAIRE

    Michihiro Osumi; Ryota Imai; Kozo Ueta; Satoshi Nobusako; Shu Morioka

    2014-01-01

    Changing the visual body appearance by use of as virtual reality system, funny mirror, or binocular glasses has been reported to be helpful in rehabilitation of pain. However, there are interindividual differences in the analgesic effect of changing the visual body image. We hypothesized that a negative body image associated with changing the visual body appearance causes interindividual differences in the analgesic effect although the relationship between the visual body appearance and analg...

  5. 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...

  6. Developing a Data-Set for Stereopsis

    Directory of Open Access Journals (Sweden)

    D.W Hunter

    2014-08-01

    Full Text Available Current research on binocular stereopsis in humans and non-human primates has been limited by a lack of available data-sets. Current data-sets fall into two categories; stereo-image sets with vergence but no ranging information (Hibbard, 2008, Vision Research, 48(12, 1427-1439 or combinations of depth information with binocular images and video taken from cameras in fixed fronto-parallel configurations exhibiting neither vergence or focus effects (Hirschmuller & Scharstein, 2007, IEEE Conf. Computer Vision and Pattern Recognition. The techniques for generating depth information are also imperfect. Depth information is normally inaccurate or simply missing near edges and on partially occluded surfaces. For many areas of vision research these are the most interesting parts of the image (Goutcher, Hunter, Hibbard, 2013, i-Perception, 4(7, 484; Scarfe & Hibbard, 2013, Vision Research. Using state-of-the-art open-source ray-tracing software (PBRT as a back-end, our intention is to release a set of tools that will allow researchers in this field to generate artificial binocular stereoscopic data-sets. Although not as realistic as photographs, computer generated images have significant advantages in terms of control over the final output and ground-truth information about scene depth is easily calculated at all points in the scene, even partially occluded areas. While individual researchers have been developing similar stimuli by hand for many decades, we hope that our software will greatly reduce the time and difficulty of creating naturalistic binocular stimuli. Our intension in making this presentation is to elicit feedback from the vision community about what sort of features would be desirable in such software.

  7. 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...

  8. 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 ...

  9. 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...

  10. [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

  11. 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...

  12. 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.

  13. 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

  14. 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...

  15. 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...

  16. Seeing the World Dimly: The Impact of Early Visual Deficits on Visual Experience in Schizophrenia

    OpenAIRE

    Kantrowitz, Joshua T.; Butler, Pamela D.; Schecter, Isaac; Silipo, Gail; Javitt, Daniel C.

    2009-01-01

    Deficits in early visual processing are well documented in schizophrenia, using methods such as contrast sensitivity. Higher, integrative stages of functioning, such as susceptibility to visual illusions, have been evaluated less extensively. For example, patients show increased susceptibility to (ie, are more easily affected by) the Muller-Lyer illusion but decreased susceptibility (ie, are less easily affected by) to stereopsis based upon binocular disparity. The basis for pattern of illusi...

  17. Consequences of retinal image clarity versus occlusion (absent) versus diffusion.

    OpenAIRE

    Jampolsky, A.

    1994-01-01

    A series of clinical questions and stated hypotheses suggested in the pre-1960s regarding the differences between stimuli of occlusion and diffusion are presented (Part I) and are answered and confirmed by a series of experiments and data in animals and humans. A diffusion stimulus is extremely destructive to development of the acuity system in an eye per se (as well as producing myopia), and a unilateral diffusion stimulus is also destructive to development of the binocular system. Real occl...

  18. 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...

  19. 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...

  20. 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...

  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. 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 ...

  8. Seed Germination of Some Crocus Species of Western Anatolia

    OpenAIRE

    HASPOLAT, Gülden; ÖZZAMBAK, M. Ercan; ŞIK, Levent

    2013-01-01

    In this study, germination studies were carried out on some Crocus species such as Crocus olivieri ssp. balansae, Crocus chrysanthus, Crocus baytopiorum, Crocus pallasii ssp. pallasii spreading at western Anatolia. Seed viability was determined by using tetrazolium test. Testa, endosperm, embryo bed of seeds were examined at stereo binocular. The pretreatments for germination were; waiting seeds in moist sand at 5oC for 4 weeks, keeping seeds for 24 hours in water and in 200400 mg/l GA3 solut...

  9. 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....

  10. Altered anterior visual system development following early monocular enucleation

    Directory of Open Access Journals (Sweden)

    Krista R. Kelly

    2014-01-01

    Conclusions: The novel finding of an asymmetry in morphology of the anterior visual system following long-term survival from early monocular enucleation indicates altered postnatal visual development. Possible mechanisms behind this altered development include recruitment of deafferented cells by crossing nasal fibres and/or geniculate cell retention via feedback from primary visual cortex. These data highlight the importance of balanced binocular input during postnatal maturation for typical anterior visual system morphology.

  11. Bird Watching in China

    Institute of Scientific and Technical Information of China (English)

    CHRIS; DEVONSHIRE-ELLIS

    2006-01-01

    Being based in, and conducting business in, some of China's largest cities is an exciting, yet stressful occupation and 1 like to relax by taking a pair of binoculars, getting out into the open air of China's huge countryside, and spending time seeing what birds I can identify. I'm not really a twitcher (one who relentlessly pursues sightings of as many different species as possible)-just happy to get into nature. In my travels around the country, I listed

  12. 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.

  13. 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...

  14. Modulating the rate and rhythmicity of perceptual rivalry alternations with the mixed 5-HT2A and 5-HT1A agonist psilocybin.

    Science.gov (United States)

    Carter, Olivia L; Pettigrew, John D; Hasler, Felix; Wallis, Guy M; Liu, Guang B; Hell, Daniel; Vollenweider, Franz X

    2005-06-01

    Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer's perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observation that the rhythmicity of perceptual alternations during binocular rivalry was greatly increased 10 h after the consumption of LSD, this study aimed to investigate the pharmacology underlying binocular rivalry and to explore the connection between the timing of perceptual switching and psychosis. Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine, PY) was chosen for the study because, like LSD, it is known to act as an agonist at serotonin (5-HT)1A and 5-HT2A receptors and to produce an altered state sometimes marked by psychosis-like symptoms. A total of 12 healthy human volunteers were tested under placebo, low-dose (115 microg/kg) and high-dose (250 microg/kg) PY conditions. In line with predictions, under both low- and high-dose conditions, the results show that at 90 min postadministration (the peak of drug action), rate and rhythmicity of perceptual alternations were significantly reduced from placebo levels. Following the 90 min testing period, the perceptual switch rate successively increased, with some individuals showing increases well beyond pretest levels at the final testing, 360 min postadministration. However, as some subjects had still not returned to pretest levels by this time, the mean phase duration at 360 min was not found to differ significantly from placebo. Reflecting the drug-induced changes in rivalry phase durations, subjects showed clear changes in psychological state as indexed by the 5D-ASC (altered states of consciousness) rating scales. This study suggests the involvement of serotonergic pathways in binocular rivalry and supports the previously proposed role of a brainstem

  15. 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...

  16. 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.

  17. 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.

  18. Abell 611: I. weak lensing analysis with LBC

    CERN Document Server

    Romano, A; Giordano, F; Maoli, R; Martini, P; Radovich, M; Scaramella, R; Antonuccio-Delogu, V; Donnarumma, A; Ettori, S; Kuijken, K; Meneghetti, M; Moscardini, L; Paulin-Henriksson, S; Giallongo, E; Ragazzoni, R; Baruffolo, A; DiPaola, A; Diolaiti, E; Fontana, A; Grazian, A; Gallozzi, S; Pedichini, F; Farinato, J; Speziali, R; Smareglia, R; Testa, V

    2010-01-01

    Aims. The Large Binocular Cameras (LBC) are two twin wide field cameras (FOV ~ 23'x 25') mounted at the prime foci of the 8.4m Large Binocular Telescope (LBT). We performed a weak lensing analysis of the z=0.288 cluster Abell 611 on g-band data obtained by the blue-optimized Large Binocular Camera in order to estimate the cluster mass. Methods. Due to the complexity of the PSF of LBC, we decided to use two different approaches, KSB and Shapelets, to measure the shape of background galaxies and to derive the shear signal produced by the cluster. Then we estimated the cluster mass with both aperture densitometry and parametric model fits. Results. The combination of the large aperture of the telescope and the wide field of view allowed us to map a region well beyond the expected virial radius of the cluster and to get a high surface density of background galaxies (23 galaxies/arcmin^2). This made possible to estimate an accurate mass for Abell 611. We find that the mass within 1.5 Mpc is: $(8\\pm3)\\times 10^{14}...

  19. 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

  20. 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

  1. 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

  2. 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.

  3. Short exposure to telestereoscope affects the oculomotor system.

    Science.gov (United States)

    Neveu, Pascaline; Priot, Anne-Emmanuelle; Plantier, Justin; Roumes, Corinne

    2010-11-01

    Under natural viewing conditions, the accommodation and vergence systems adjust the focus and the binocular alignment of the eyes in response to changes in viewing distance. The two responses are linked via cross-coupling and proceed almost simultaneously. Some optical devices, such as virtual reality or helmet mounted displays, create an oculomotor conflict by modifying demands on both vergence and accommodation. Previous studies extensively investigated the effect of such a conflict on the cross-coupling between vergence and accommodation, but little is known about the plasticity of the whole oculomotor system. In the present study, an oculomotor conflict was induced by a telestereoscope which magnified the standard inter-pupillary separation threefold and thus increased the convergence demand while accommodation remained almost unchanged. The effect of a 10 min exposure was assessed via a series of optometric parameters selected on the basis of existing oculomotor models. Associated with subject's visual complaints, most of the oculomotor parameters tested were modified: there was (1) deterioration of stereoscopic threshold; (2) increase in AC/A ratio; (3) increase in near and far phorias; and (4) shift of the zone of clear and single binocular vision towards convergence. These results showed a change in gain of accommodative vergence and a shift of vergence reserves towards convergence in response to telestereoscopic viewing. The subject's binocular behaviour tended towards esophoria with convergence excess as confirmed by Sheard's and Percival's criteria. Such changes in oculomotor parameters support adaptive behaviour linked with telestereoscopic viewing.

  4. 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

  5. Six-month-old infants' perception of the hollow face illusion: evidence for a general convexity bias.

    Science.gov (United States)

    Corrow, Sherryse L; Mathison, Jordan; Granrud, Carl E; Yonas, Albert

    2014-01-01

    Corrow, Granrud, Mathison, and Yonas (2011, Perception, 40, 1376-1383) found evidence that 6-month-old infants perceive the hollow face illusion. In the present study we asked whether 6-month-old infants perceive illusory depth reversal for a nonface object and whether infants' perception of the hollow face illusion is affected by mask orientation inversion. In experiment 1 infants viewed a concave bowl, and their reaches were recorded under monocular and binocular viewing conditions. Infants reached to the bowl as if it were convex significantly more often in the monocular than in the binocular viewing condition. These results suggest that infants perceive illusory depth reversal with a nonface stimulus and that the infant visual system has a bias to perceive objects as convex. Infants in experiment 2 viewed a concave face-like mask in upright and inverted orientations. Infants reached to the display as if it were convex more in the monocular than in the binocular condition; however, mask orientation had no effect on reaching. Previous findings that adults' perception of the hollow face illusion is affected by mask orientation inversion have been interpreted as evidence of stored-knowledge influences on perception. However, we found no evidence of such influences in infants, suggesting that their perception of this illusion may not be affected by stored knowledge, and that perceived depth reversal is not face-specific in infants.

  6. 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.

  7. Interocular transfer of spatial adaptation is weak at low spatial frequencies.

    Science.gov (United States)

    Baker, Daniel H; Meese, Tim S

    2012-06-15

    Adapting one eye to a high contrast grating reduces sensitivity to similar target gratings shown to the same eye, and also to those shown to the opposite eye. According to the textbook account, interocular transfer (IOT) of adaptation is around 60% of the within-eye effect. However, most previous studies on this were limited to using high spatial frequencies, sustained presentation, and criterion-dependent methods for assessing threshold. Here, we measure IOT across a wide range of spatiotemporal frequencies, using a criterion-free 2AFC method. We find little or no IOT at low spatial frequencies, consistent with other recent observations. At higher spatial frequencies, IOT was present, but weaker than previously reported (around 35%, on average, at 8c/deg). Across all conditions, monocular adaptation raised thresholds by around a factor of 2, and observers showed normal binocular summation, demonstrating that they were not binocularly compromised. These findings prompt a reassessment of our understanding of the binocular architecture implied by interocular adaptation. In particular, the output of monocular channels may be available to perceptual decision making at low spatial frequencies.

  8. 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

  9. 3D Perception of Biomimetic Eye Based on Motion Vision and Stereo Vision%仿生眼运动视觉与立体视觉3维感知

    Institute of Scientific and Technical Information of China (English)

    王庆滨; 邹伟; 徐德; 张峰

    2015-01-01

    In order to overcome the narrow visual field of binocular vision and the low precision of monocular vision, a binocular biomimetic eye platform with 4 rotational degrees of freedom is designed based on the structural characteristics of human eyes, so that the robot can achieve human-like environment perception with binocular stereo vision and monoc-ular motion vision. Initial location and parameters calibration of the biomimetic eye platform are accomplished based on the vision alignment strategy and hand-eye calibration. The methods of binocular stereo perception and monocular motion stereo perception are given based on the dynamically changing external parameters. The former perceives the 3D information through the two images obtained by two cameras in real-time and their relative posture, and the latter perceives the 3D infor-mation by synthesize multiple images obtained by one camera and its corresponding postures at multiple adjacent moments. Experimental results shows that the relative perception accuracy of binocular vision is 0.38% and the relative perception accuracy of monocular motion vision is 0.82%. In conclusion, the method proposed can broaden the field of binocular vision, and ensure the accuracy of binocular perception and monocular motion perception.%为使机器人同时具备双目立体视觉和单目运动视觉的仿人化环境感知能力,克服双目视场狭窄、单目深度感知精度低的缺陷,本文基于人眼结构特点,设计了一个具有4个旋转自由度的双目仿生眼平台,并分别基于视觉对准策略和手眼标定技术实现了该平台的初始定位和参数标定.给出了基于外部参数动态变化的双目立体感知方法和单目运动立体感知方法,前者通过两架摄像机实时获取的图像信息以及摄像机相对位姿信息进行3维感知,后者综合利用单个摄像机在多个相邻时刻获取的多个图像及其对应姿态进行3维感知.实验结果中的双目

  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. 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

  12. 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

  13. 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

  14. 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

  15. Deep Multi-telescope Photometry of NGC 5466. II. The Radial Behavior of the Mass Function Slope

    Science.gov (United States)

    Beccari, G.; Dalessandro, E.; Lanzoni, B.; Ferraro, F. R.; Bellazzini, M.; Sollima, A.

    2015-12-01

    We use a combination of data acquired with the Advanced Camera for Survey on board the Hubble Space Telescope and the Large Binocular Camera (LBC-blue) mounted on the Large Binocular Telescope to sample the main sequence (MS) stars of the globular cluster (GC) NGC 5466 in the mass range 0.3 law mass function in the form dN/dm \\propto {m}α by the derivative of the mass-luminosity relationship of the best-fit isochrone. We find that α varies from -0.6 in the core region to -1.9 in the outer region. This fact allows us to prove by observation that the stars in NGC 5466 have experienced the effects of mass segregation. We compare the radial variation of α from the center out to 5 core radii (rc) in NGC 5466 and the GC M10, finding that the gradient of α in the first 5rc is more than a factor of 2 shallower in NGC 5466 than in M10, in line with the differences in the clusters’ relaxation timescales. NGC 5466 is dynamically younger than M10, with two-body relaxation processes only recently starting to shape the distribution of MS stars. This result fully agrees with the conclusion obtained in our previous works on the radial distribution of blue straggler stars, further confirming that this can be used as an efficient clock to measure the dynamical age of stellar systems. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

  16. 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.

  17. 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

  18. Comparison of visual outcomes and subjective visual quality after bilateral implantation of a diffractive trifocal intraocular lens and blended implantation of apodized diffractive bifocal intraocular lenses

    Science.gov (United States)

    Gundersen, Kjell Gunnar; Potvin, Rick

    2016-01-01

    Purpose To compare the visual acuity (VA) and quality of vision between bilateral implantation of a trifocal intraocular lens (IOL) and blended bifocal IOLs with an intermediate add in the dominant eye and a near add in the nondominant eye. Patients and methods Patients with either trifocal or blended bifocal IOLs implanted were recruited after surgery. Subjects returned for a single diagnostic visit between 3 and 24 months after surgery. VA was tested at various distances, including low-contrast acuity and acuity at their preferred reading distance. A binocular defocus curve was obtained, and subjective visual function and quality of vision were evaluated. Results Twenty-five trifocal subjects and 30 blended bifocal subjects were enrolled. There were no significant differences in low-contrast acuity, preferred reading distance, or acuity at that reading distance. Binocular vision at 4 m, 60 cm, and 40 cm was not statistically significantly different. The trifocal provided statistically significantly better visual acuity (P<0.05) at vergences from −0.5 to −1.5 D (from 2 m to 67 cm viewing distance, P<0.05). There was no statistically significant difference in the near vision subscale scores of the 39-question National Eye Institute Visual Function Questionnaire or the overall scores of the Quality of Vision questionnaire, though significantly more trifocal subjects reported that the observed visual disturbances were “bothersome” (P<0.05). Conclusion Both lens modalities provided subjects with excellent binocular near and distance vision, with similar low rates of visual disturbances and good reported functional vision. The trifocal IOL provided significantly better intermediate VA in the viewing distance range of 2 m to 67 cm, corresponding to viewing things such as a car dashboard or grocery shelf. VA was similar between groups at viewing distances from 60 to 40 cm, corresponding to computer or reading distance. PMID:27274184

  19. Visual acuity and patient satisfaction at varied distances and lighting conditions after implantation of an aspheric diffractive multifocal one-piece intraocular lens

    Science.gov (United States)

    Chang, Daniel H

    2016-01-01

    Purpose The aim of the study is to evaluate the visual acuity and patient satisfaction at varied distances under photopic and mesopic lighting conditions in patients bilaterally implanted with aspheric diffractive multifocal one-piece intraocular lenses. Methods In this retrospective–prospective study, 16 patients with a mean age of 66.2±9.2 years (range: 50–81 years) who had undergone bilateral phacoemulsification surgery with implantation of a Tecnis multifocal one-piece intraocular lens (ZMB00) were evaluated. Monocular and binocular uncorrected and distance-corrected visual acuities were measured at distance (20 ft), intermediate (70–80 cm), and near (35–40 cm) under photopic (85 cd/m2) and mesopic (3 cd/m2) lighting conditions and were compared using the paired t-test. All patients also completed a subjective questionnaire. Results At a mean follow-up of 9.5±3.9 months, distance, near, and intermediate visual acuity improved significantly from preoperative acuity. Under photopic and mesopic conditions, 93.8% and 62.5% of patients, respectively, had binocular uncorrected intermediate visual acuity of 20/40 or better, and 62.5% and 31.3% of patients had binocular uncorrected near visual acuity of 20/20 or better. All patients were satisfied with their overall vision without using glasses and/or contact lenses when compared with before surgery. A total of 87.5% of patients reported no glare and 68.8% of patients reported no halos around lights at night. Conclusion Tecnis multifocal one-piece intraocular lenses provide good distance, intermediate, and near visual acuity under photopic as well as mesopic lighting conditions. High levels of spectacle independence with low levels of photic phenomenon were achieved, resulting in excellent patient satisfaction. PMID:27536061

  20. 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.