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Baldwin AS, Min SH, Alarcon Carrillo S, Wang Z, Cheng Z, Zhou J, Hess RF. Stereo-anomaly is found more frequently in tasks that require discrimination between depths. iScience 2024; 27:109879. [PMID: 38812554 PMCID: PMC11134555 DOI: 10.1016/j.isci.2024.109879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/28/2024] [Accepted: 04/29/2024] [Indexed: 05/31/2024] Open
Abstract
Within the population of humans with otherwise normal vision, there exists some proportion whose ability to perceive depth from binocular disparity is poor or absent. The prevalence of this "stereo-anomaly" has been reported to be as small as 2%, or as great as 30%. We set out to investigate this discrepancy. We used a digital tool to measure stereoacuity in tasks requiring either the detection of disparity or the discrimination of the direction of disparity. In a cohort of 228 participants, we found that 98% were able to consistently perform the detection task. Of these, only 69% consistently performed the discrimination task. The 31% of participants who had difficulty with the discrimination task could further be divided into 17% who were consistently unable to perform the task and 14% who showed limited ability. This suggests that identification of the direction of disparity requires further processing beyond merely detecting its presence.
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Affiliation(s)
- Alex S. Baldwin
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada
| | - Seung Hyun Min
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada
| | - Sara Alarcon Carrillo
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada
| | - Zili Wang
- The Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ziyun Cheng
- The Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jiawei Zhou
- The Eye Hospital, School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Robert F. Hess
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada
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Clayton R, Siderov J. Differences in stereoacuity between crossed and uncrossed disparities reduce with practice. Ophthalmic Physiol Opt 2022; 42:1353-1362. [PMID: 35997266 PMCID: PMC9804356 DOI: 10.1111/opo.13040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Stereoacuity, like many forms of hyperacuity, improves with practice. We investigated the effects of repeated measurements over multiple visits on stereoacuity using two commonly utilised clinical stereotests, for both crossed and uncrossed disparity stimuli. METHODS Participants were adults with normal binocular vision (n = 17) aged between 18 and 50 years. Stereoacuity was measured using the Randot and TNO stereotests on five separate occasions over a six week period. We utilised both crossed and uncrossed stimuli to separately evaluate stereoacuity in both disparity directions. A subset of the subject group also completed a further five visits over an additional six week period. Threshold stereoacuity was determined by the lowest disparity level at which the subjects could correctly identify both the position and disparity direction (crossed or uncrossed) of the stimulus. Data were analysed by repeated measures analysis of variance. RESULTS Stereoacuity for crossed and uncrossed stimuli improved significantly across the first five visits (F1,21 = 4.24, p = 0.05). The main effect of disparity direction on stereoacuity was not significant (F1 = 0.02, p = 0.91). However, a significant interaction between disparity direction and stereotest was identified (F1 = 7.92, p = 0.01). CONCLUSIONS Stereoacuity measured with both the TNO and Randot stereotests improved significantly over the course of five repetitions. Although differences between crossed and uncrossed stereoacuity were evident, they depended on the stereotest used and reduced or disappeared after repeated measurements. A single measure of stereoacuity is inadequate for properly evaluating adult stereopsis clinically.
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Affiliation(s)
- Robin Clayton
- Centre for Vision across the Life Span, Department of Optometry and Vision SciencesUniversity of HuddersfieldHuddersfieldUK
| | - John Siderov
- Centre for Vision across the Life Span, Department of Optometry and Vision SciencesUniversity of HuddersfieldHuddersfieldUK
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3
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Höhler C, Rasamoel ND, Rohrbach N, Hansen JP, Jahn K, Hermsdörfer J, Krewer C. The impact of visuospatial perception on distance judgment and depth perception in an Augmented Reality environment in patients after stroke: an exploratory study. J Neuroeng Rehabil 2021; 18:127. [PMID: 34419086 PMCID: PMC8379833 DOI: 10.1186/s12984-021-00920-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 07/29/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Augmented Reality (AR)-based interventions are applied in neurorehabilitation with increasing frequency. Depth perception is required for the intended interaction within AR environments. Until now, however, it is unclear whether patients after stroke with impaired visuospatial perception (VSP) are able to perceive depth in the AR environment. METHODS Different aspects of VSP (stereovision and spatial localization/visuoconstruction) were assessed in 20 patients after stroke (mean age: 64 ± 14 years) and 20 healthy subjects (HS, mean age: 28 ± 8 years) using clinical tests. The group of HS was recruited to assess the validity of the developed AR tasks in testing stereovision. To measure perception of holographic objects, three distance judgment tasks and one three-dimensionality task were designed. The effect of impaired stereovision on performance in each AR task was analyzed. AR task performance was modeled by aspects of VSP using separate regression analyses for HS and for patients. RESULTS In HS, stereovision had a significant effect on the performance in all AR distance judgment tasks (p = 0.021, p = 0.002, p = 0.046) and in the three-dimensionality task (p = 0.003). Individual quality of stereovision significantly predicted the accuracy in each distance judgment task and was highly related to the ability to perceive holograms as three-dimensional (p = 0.001). In stroke-survivors, impaired stereovision had a specific deterioration effect on only one distance judgment task (p = 0.042), whereas the three-dimensionality task was unaffected (p = 0.317). Regression analyses confirmed a lacking impact of patients' quality of stereovision on AR task performance, while spatial localization/visuoconstruction significantly prognosticated the accuracy in distance estimation of geometric objects in two AR tasks. CONCLUSION Impairments in VSP reduce the ability to estimate distance and to perceive three-dimensionality in an AR environment. While stereovision is key for task performance in HS, spatial localization/visuoconstruction is predominant in patients. Since impairments in VSP are present after stroke, these findings might be crucial when AR is applied for neurorehabilitative treatment. In order to maximize the therapy outcome, the design of AR games should be adapted to patients' impaired VSP. Trial registration: The trial was not registered, as it was an observational study.
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Affiliation(s)
- Chiara Höhler
- Technical University of Munich, Georg-Brauchle Ring 60/62, 80992, Munich, Germany.
- Schoen Clinic Bad Aibling, Kolbermoorer Strasse 72, 83043, Bad Aibling, Germany.
| | - Nils David Rasamoel
- Technical University of Denmark, Anker Engelunds Vej 1, 2800, Kgs. Lyngby, Denmark
| | - Nina Rohrbach
- Technical University of Munich, Georg-Brauchle Ring 60/62, 80992, Munich, Germany
| | - John Paulin Hansen
- Technical University of Denmark, Anker Engelunds Vej 1, 2800, Kgs. Lyngby, Denmark
| | - Klaus Jahn
- Schoen Clinic Bad Aibling, Kolbermoorer Strasse 72, 83043, Bad Aibling, Germany
- Ludwig-Maximilians University of Munich, University Hospital Grosshadern, Marchioninistrasse 15, 81377, Munich, Germany
| | - Joachim Hermsdörfer
- Technical University of Munich, Georg-Brauchle Ring 60/62, 80992, Munich, Germany
| | - Carmen Krewer
- Technical University of Munich, Georg-Brauchle Ring 60/62, 80992, Munich, Germany
- Schoen Clinic Bad Aibling, Kolbermoorer Strasse 72, 83043, Bad Aibling, Germany
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Kim NG, Lee HW. Stereoscopic Depth Perception and Visuospatial Dysfunction in Alzheimer's Disease. Healthcare (Basel) 2021; 9:healthcare9020157. [PMID: 33546119 PMCID: PMC7913121 DOI: 10.3390/healthcare9020157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 11/16/2022] Open
Abstract
With visuospatial dysfunction emerging as a potential marker that can detect Alzheimer's disease (AD) even in its earliest stages and with disturbance in stereopsis suspected to be the prime contributor to visuospatial deficits in AD, we assessed stereoscopic abilities of patients with AD and mild cognitive impairment (MCI). Whereas previous research assessing patients' stereoacuity has yielded mixed results, we assessed patients' capacity to process coarse disparities that can convey adequate depth information about objects in the environment. We produced two virtual cubes at two different distances from the observer by manipulating disparity type (absolute vs. relative), disparity direction (crossed vs. uncrossed) and disparity magnitude, then had participants judge the object that appeared closer to them. Two patient groups performed as well as, or even better than elderly controls, suggesting that AD patients' coarse disparity processing capacity is capable of supporting common tasks involving reaching, grasping, driving, and navigation. Results may help researchers narrow down the exact cause(s) of visuospatial deficits in AD and develop and validate measures to assess visuospatial dysfunction in clinical trials and disease diagnosis.
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Affiliation(s)
- Nam-Gyoon Kim
- Department of Psychology, Keimyung University, Daegu 42601, Korea
- Correspondence: ; Tel.: +82-53-580-5415
| | - Ho-Won Lee
- Department of Neurology, School of Medicine & Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
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Chauhan T, Héjja-Brichard Y, Cottereau BR. Modelling binocular disparity processing from statistics in natural scenes. Vision Res 2020; 176:27-39. [DOI: 10.1016/j.visres.2020.07.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 07/19/2020] [Accepted: 07/20/2020] [Indexed: 11/25/2022]
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Alarcon Carrillo S, Baldwin AS, Hess RF. Factors limiting sensitivity to binocular disparity in human vision: Evidence from a noise-masking approach. J Vis 2020; 20:9. [PMID: 32232374 PMCID: PMC7405759 DOI: 10.1167/jov.20.3.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 11/15/2019] [Indexed: 11/24/2022] Open
Abstract
Our visual system uses the disparity between the images received by the two eyes to judge three-dimensional distance to surfaces. We can measure this ability by having subjects discriminate the disparity of rendered surfaces. We wanted to know the basis of the individual differences in this ability. We tested 53 adults with normal vision using a relative disparity detection task. Targets were wedge-shaped surfaces formed from random dots. These were presented in either crossed or uncrossed disparity relative to a random dot background. The threshold disparity ranged from 24 arc seconds in the most-able subject to 275 arc seconds in the least-able subject. There was a small advantage for detecting crossed-disparity targets. We used the noise-masking paradigm to partition subject performance into two factors. These were the subject's equivalent internal noise and their processing efficiency. The parameters were estimated by fitting the linear amplifier model. We found both factors contributed to the individual differences in stereoacuity. Within subjects, those showing an advantage for one disparity direction had enhanced efficiency for that direction. Some subjects had a higher equivalent internal noise for one direction that was balanced out by an increased efficiency. Our approach provides a more thorough account of the stereo-ability of our subjects compared with measuring thresholds alone. We present a normative set of results that can be compared with clinical populations.
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Affiliation(s)
- Sara Alarcon Carrillo
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, Quebec, Canada
| | - Alex S. Baldwin
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, Quebec, Canada
| | - Robert F. Hess
- McGill Vision Research, Department of Ophthalmology & Visual Sciences, McGill University, Montreal, Quebec, Canada
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Chopin A, Bavelier D, Levi DM. The prevalence and diagnosis of 'stereoblindness' in adults less than 60 years of age: a best evidence synthesis. Ophthalmic Physiol Opt 2019; 39:66-85. [PMID: 30776852 DOI: 10.1111/opo.12607] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/23/2019] [Indexed: 12/21/2022]
Abstract
PURPOSE Stereoscopic vision (or stereopsis) is the ability to perceive depth from binocular disparity - the difference of viewpoints between the two eyes. Interestingly, there are large individual differences as to how well one can appreciate depth from such a cue. The total absence of stereoscopic vision, called 'stereoblindness', has been associated with negative behavioural outcomes such as poor distance estimation. Surprisingly, the prevalence of stereoblindness remains unclear, as it appears highly dependent on the way in which stereopsis is measured. RECENT FINDINGS This review highlights the fact that stereopsis is not a unitary construct, but rather implies different systems. The optimal conditions for measuring these varieties of stereoscopic information processing are discussed given the goal of detecting stereoblindness, using either psychophysical or clinical stereotests. In that light, we then discuss the estimates of stereoblindness prevalence of past studies. SUMMARY We identify four different approaches that all converge toward a prevalence of stereoblindness of 7% (median approach: 7%; unambiguous-stereoblindness-criteria approach: 7%; visual-defect-included approach: 7%; multiple-criteria approach: 7%). We note that these estimates were derived considering adults of age <60 years old. Older adults may have a higher prevalence. Finally, we make recommendations for a new ecological definition of stereoblindness and for efficient clinical methods for determining stereoblindness by adapting existing tools.
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Affiliation(s)
- Adrien Chopin
- Faculte de Psychologie et Sciences de l'Education, University of Geneva, Geneva, Switzerland.,Campus Biotech, Geneva, Switzerland
| | - Daphne Bavelier
- Faculte de Psychologie et Sciences de l'Education, University of Geneva, Geneva, Switzerland.,Campus Biotech, Geneva, Switzerland
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Fixating at far distance shortens reaction time to peripheral visual stimuli at specific locations. Neurosci Lett 2018; 664:15-19. [PMID: 29126774 DOI: 10.1016/j.neulet.2017.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/04/2017] [Accepted: 11/06/2017] [Indexed: 11/24/2022]
Abstract
The purpose of the present study was to examine whether the fixation distance in real three-dimensional space affects manual reaction time to peripheral visual stimuli. Light-emitting diodes were used for presenting a fixation point and four peripheral visual stimuli. The visual stimuli were located at a distance of 45cm and at 25° in the left, right, upper, and lower directions from the sagittal axis including the fixation point. Near (30cm), Middle (45cm), Far (90cm), and Very Far (300cm) fixation distance conditions were used. When one of the four visual stimuli was randomly illuminated, the participants released a button as quickly as possible. Results showed that overall peripheral reaction time decreased as the fixation distance increased. The significant interaction between fixation distance and stimulus location indicated that the effect of fixation distance on reaction time was observed at the left, right, and upper locations but not at the lower location. These results suggest that fixating at far distance would contribute to faster reaction and that the effect is specific to locations in the peripheral visual field. The present findings are discussed in terms of viewer-centered representation, the focus of attention in depth, and visual field asymmetry related to neurological and psychological aspects.
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Horváth G, Nemes VA, Radó J, Czigler A, Török B, Buzás P, Jandó G. Simple reaction times to cyclopean stimuli reveal that the binocular system is tuned to react faster to near than to far objects. PLoS One 2018; 13:e0188895. [PMID: 29304135 PMCID: PMC5755738 DOI: 10.1371/journal.pone.0188895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/15/2017] [Indexed: 12/26/2022] Open
Abstract
Binocular depth perception is an important mechanism to segregate the visual scene for mapping relevant objects in our environment. Convergent evidence from psychophysical and neurophysiological studies have revealed asymmetries between the processing of near (crossed) and far (uncrossed) binocular disparities. The aim of the present study was to test if near or far objects are processed faster and with higher contrast sensitivity in the visual system. We therefore measured the relationship between binocular disparity and simple reaction time (RT) as well as contrast gain based on the contrast-RT function in young healthy adults. RTs were measured to suddenly appearing cyclopean target stimuli, which were checkerboard patterns encoded by depth in dynamic random dot stereograms (DRDS). The DRDS technique allowed us to selectively study the stereoscopic processing system by eliminating all monocular cues. The results showed that disparity and contrast had significant effects on RTs. RTs as a function of disparity followed a U-shaped tuning curve indicating an optimum at around 15 arc min, where RTs were minimal. Surprisingly, the disparity tuning of RT was much less pronounced for far disparities. At the optimal disparity, we measured advantages of about 80 ms and 30 ms for near disparities at low (10%) and high (90%) contrasts, respectively. High contrast always reduced RTs as well as the disparity dependent differences. Furthermore, RT-based contrast gains were higher for near disparities in the range of disparities where RTs were the shortest. These results show that the sensitivity of the human visual system is biased for near versus far disparities and near stimuli can result in faster motor responses, probably because they bear higher biological relevance.
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Affiliation(s)
- Gábor Horváth
- Institute of Physiology, University of Pécs Medical School, Pécs, Hungary
| | - Vanda A. Nemes
- Institute of Physiology, University of Pécs Medical School, Pécs, Hungary
| | - János Radó
- Institute of Physiology, University of Pécs Medical School, Pécs, Hungary
| | - András Czigler
- Institute of Physiology, University of Pécs Medical School, Pécs, Hungary
| | - Béla Török
- Department of Ophthalmology, Kantonsspital, St. Gallen, Switzerland
| | - Péter Buzás
- Institute of Physiology, University of Pécs Medical School, Pécs, Hungary
| | - Gábor Jandó
- Institute of Physiology, University of Pécs Medical School, Pécs, Hungary
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Dorman R, van Ee R. 50 Years of Stereoblindness: Reconciliation of a Continuum of Disparity Detectors With Blindness for Disparity in Near or Far Depth. Iperception 2017; 8:2041669517738542. [PMID: 29201340 PMCID: PMC5697597 DOI: 10.1177/2041669517738542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Whitman Richards (1932–2016) discovered some 50 years ago that about 30% of observers from the normal population exhibit stereoblindness: the disability to process binocular disparities in either far or near depth. We review the literature on stereoblindness entailing two insights. First, contemporary scholars in stereopsis undervalue the comprehension that disparity processing studies require precise assessments of observers’ stereoblindness. We argue that this frequently leads to suboptimal interpretations. Second, there is still an open conundrum: How can the established finding that disparity is processed by a continuum of detectors be reconciled with the disability of many observers to process a whole class of far or near disparities? We propose, based upon integration of literature, that an asymmetry between far and near disparity detection at birth—being present for a variety of reasons—can suppress the typical formation of binocular correlation during the critical period for the development of stereopsis early in life, thereby disabling a whole class of far or near disparities.
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Affiliation(s)
- Reinder Dorman
- Cognitive and Systems Neuroscience Group, Swammerdam Institute for Life Science, University of Amsterdam, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands
| | - Raymond van Ee
- Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, The Netherlands; Department of Brain and Cognition, University of Leuven, Belgium; Department of Brain, Behavior and Cognition, Philips Research, Eindhoven, The Netherlands
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Talbot D, Van der Burg E, Cass J. Stereoscopic Segmentation Cues Improve Visual Timing Performance in Spatiotemporally Cluttered Environments. Iperception 2017; 8:2041669517699222. [PMID: 28491271 PMCID: PMC5405908 DOI: 10.1177/2041669517699222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Recently, Cass and Van der Burg demonstrated that temporal order judgment (TOJ) precision could be profoundly impaired by the mere presence of dynamic visual clutter elsewhere in the visual field. This study examines whether presenting target and distractor objects in different depth planes might ameliorate this remote temporal camouflage (RTC) effect. TOJ thresholds were measured under static and dynamic (flickering) distractor conditions. In Experiment 1, targets were presented at zero, crossed, or uncrossed disparity, with distractors fixed at zero disparity. Thresholds were significantly elevated under dynamic compared with static contextual conditions, replicating the RTC effect. Crossed but not uncrossed disparity targets improved performance in dynamic distractor contexts, which otherwise produce substantial RTC. In Experiment 2, the assignment of disparity was reversed: targets fixed at zero disparity; distractors crossed, uncrossed, or zero. Under these conditions, thresholds improved significantly in the nonzero distractor disparity conditions. These results indicate that presenting target and distractor objects in different planes can significantly improve TOJ performance in dynamic conditions. In Experiment 3, targets were each presented with a different sign of disparity (e.g., one crossed and the other uncrossed), with no resulting performance benefits. Results suggest that disparity can be used to alleviate the performance-diminishing effects of RTC, but only if both targets constitute a single and unique disparity-defined surface.
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Affiliation(s)
- Daniel Talbot
- School of Social Science and Psychology, Western Sydney University, Australia
| | - Erik Van der Burg
- Department of Experimental and Applied Psychology, Vrije Universiteit Amsterdam, The Netherlands; School of Psychology, University of Sydney, Australia
| | - John Cass
- School of Social Science and Psychology, Western Sydney University, Australia
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12
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Binocular vision in infancy: Responsiveness to uncrossed horizontal disparity. Infant Behav Dev 2016; 44:219-26. [DOI: 10.1016/j.infbeh.2016.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/07/2016] [Indexed: 11/19/2022]
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Sensory uncertainty leads to systematic misperception of the direction of motion in depth. Atten Percept Psychophys 2015; 77:1685-96. [PMID: 25828462 DOI: 10.3758/s13414-015-0881-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although we have made major advances in understanding motion perception based on the processing of lateral (2D) motion signals on computer displays, the majority of motion in the real (3D) world occurs outside of the plane of fixation, and motion directly toward or away from observers has particular behavioral relevance. Previous work has reported a systematic lateral bias in the perception of 3D motion, such that an object on a collision course with an observer's head is frequently judged to miss it, with obvious negative consequences. To better understand this bias, we systematically investigated the accuracy of 3D motion perception while manipulating sensory noise by varying the contrast of a moving target and its position in depth relative to fixation. Inconsistent with previous work, we found little bias under low sensory noise conditions. With increased sensory noise, however, we revealed a novel perceptual phenomenon: observers demonstrated a surprising tendency to confuse the direction of motion-in-depth, such that approaching objects were reported to be receding and vice versa. Subsequent analysis revealed that the lateral and motion-in-depth components of observers' reports are similarly affected, but that the effects on the motion-in-depth component (i.e., the motion-in-depth confusions) are much more apparent than those on the lateral component. In addition to revealing this novel visual phenomenon, these results shed new light on errors that can occur in motion perception and provide a basis for continued development of motion perception models. Finally, our findings suggest methods to evaluate the effectiveness of 3D visualization environments, such as 3D movies and virtual reality devices.
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Functional architecture for disparity in macaque inferior temporal cortex and its relationship to the architecture for faces, color, scenes, and visual field. J Neurosci 2015; 35:6952-68. [PMID: 25926470 DOI: 10.1523/jneurosci.5079-14.2015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Binocular disparity is a powerful depth cue for object perception. The computations for object vision culminate in inferior temporal cortex (IT), but the functional organization for disparity in IT is unknown. Here we addressed this question by measuring fMRI responses in alert monkeys to stimuli that appeared in front of (near), behind (far), or at the fixation plane. We discovered three regions that showed preferential responses for near and far stimuli, relative to zero-disparity stimuli at the fixation plane. These "near/far" disparity-biased regions were located within dorsal IT, as predicted by microelectrode studies, and on the posterior inferotemporal gyrus. In a second analysis, we instead compared responses to near stimuli with responses to far stimuli and discovered a separate network of "near" disparity-biased regions that extended along the crest of the superior temporal sulcus. We also measured in the same animals fMRI responses to faces, scenes, color, and checkerboard annuli at different visual field eccentricities. Disparity-biased regions defined in either analysis did not show a color bias, suggesting that disparity and color contribute to different computations within IT. Scene-biased regions responded preferentially to near and far stimuli (compared with stimuli without disparity) and had a peripheral visual field bias, whereas face patches had a marked near bias and a central visual field bias. These results support the idea that IT is organized by a coarse eccentricity map, and show that disparity likely contributes to computations associated with both central (face processing) and peripheral (scene processing) visual field biases, but likely does not contribute much to computations within IT that are implicated in processing color.
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Abstract
A great challenge of systems neuroscience is to understand the computations that underlie perceptual constancies, the ability to represent behaviorally relevant stimulus properties as constant even when irrelevant stimulus properties vary. As signals proceed through the visual system, neural states become more selective for properties of the environment, and more invariant to irrelevant features of the retinal images. Here, we describe a method for determining the computations that perform these transformations optimally, and apply it to the specific computational task of estimating a powerful depth cue: binocular disparity. We simultaneously determine the optimal receptive field population for encoding natural stereo images of locally planar surfaces and the optimal nonlinear units for decoding the population responses into estimates of disparity. The optimal processing predicts well-established properties of neurons in cortex. Estimation performance parallels important aspects of human performance. Thus, by analyzing the photoreceptor responses to natural images, we provide a normative account of the neurophysiology and psychophysics of absolute disparity processing. Critically, the optimal processing rules are not arbitrarily chosen to match the properties of neurophysiological processing, nor are they fit to match behavioral performance. Rather, they are dictated by the task-relevant statistical properties of complex natural stimuli. Our approach reveals how selective invariant tuning-especially for properties not trivially available in the retinal images-could be implemented in neural systems to maximize performance in particular tasks.
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Affiliation(s)
- Johannes Burge
- Center for Perceptual Systems and Department of Psychology, University of Texas at Austin, Austin, TX, USA
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The effects of interocular correlation and contrast on stereoscopic depth magnitude estimation. Optom Vis Sci 2008; 85:164-73. [PMID: 18317331 DOI: 10.1097/opx.0b013e3181643e65] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Decreasing the interocular correlation in random dot stereograms elevates disparity detection thresholds. Whether decorrelation also affects perceived depth from suprathreshold disparity magnitudes is unknown. The present study investigated the effects of interocular correlation and contrast on the magnitude of perceived depth in suprathreshold random dot stereograms. METHODS Stereoscopic depth magnitude estimation as a function of percent interocular correlation of dynamic random dot stimuli was measured for five human subjects with clinically normal binocular vision. Each trial's stimulus was randomly assigned one of two magnitudes of either crossed or uncrossed relative disparity. Subjects verbally reported the direction and magnitude of perceived relative depth for each trial using a modulus-free scale. Normalized depth magnitude estimations as a function of the percent interocular correlation demonstrated the relationship between perceived depth, interocular correlation and contrast within subjects. Inter-subject variability was examined with comparisons of data across subjects. RESULTS The depth magnitude perceived for a given magnitude of disparity declined as the percent of correlation of elements between the eyes decreased for both crossed and uncrossed directions. The effect generally was greater for uncrossed disparities and lower contrast. Some subjects demonstrated asymmetries in perceived depth for crossed vs. uncrossed disparities of the same magnitude. CONCLUSIONS Magnitude estimation of suprathreshold stimuli provided a method of studying performance characteristics of stereoscopic depth perception across the range of functional disparities. Differences found in depth magnitude estimation as a function of the sign of disparity suggest that the neural mechanisms underlying depth perception from uncrossed disparity are more sensitive to image decorrelation, particularly at low contrast, than the mechanisms underlying depth estimation from crossed disparity. These results could occur from differences in near and far disparity-sensitive neurons, from the geometrical relationship between disparity and physical distance in normal viewing, or from the response measure independent of perception.
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Wilmer JB. How to use individual differences to isolate functional organization, biology, and utility of visual functions; with illustrative proposals for stereopsis. SPATIAL VISION 2008; 21:561-79. [PMID: 19017483 PMCID: PMC2586597 DOI: 10.1163/156856808786451408] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This paper is a call for greater use of individual differences in the basic science of visual perception. Individual differences yield insights into visual perception's functional organization, underlying biological/environmental mechanisms, and utility. I first explain the general approach advocated and where it comes from. Second, I describe five principles central to learning about the nature of visual perception through individual differences. Third, I elaborate on the use of individual differences to gain insights into the three areas mentioned above (function, biology/environment, utility), in each case describing the approach advocated, presenting model examples from the literature, and laying out illustrative research proposals for the case of stereopsis.
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Affiliation(s)
- Jeremy B Wilmer
- SUNY State College of Optometry, Vision Sciences, 33 West 42nd Street, New York, NY 10036, USA.
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Mitsudo H, Nakamizo S, Ono H. A long-distance stereoscopic detector for partially occluding surfaces. Vision Res 2006; 46:1180-6. [PMID: 16249014 DOI: 10.1016/j.visres.2005.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 09/12/2005] [Accepted: 09/12/2005] [Indexed: 12/01/2022]
Abstract
An external noise technique was used to investigate the stereoscopic process that generates an illusory phantom occluder from binocularly unmatched elements. Observers were required to identify the quadrant in which a binocularly defined target was presented. We had three targets: (a) two vertical binocular bars with the unmatched portions arranged to induce a stable phantom occluder (valid), (b) the same stimuli except the image for the left eye was switched with that for the right eye therefore not inducing a stable occluder (invalid), and (c) a single binocular bar with the same unmatched portion (single-bar). For each target, the luminance contrast of the signal required for 75% correct responses was measured at four levels of external interocular noise. Contrast thresholds were found to be lower for the valid target than for both the invalid and the single-bar targets. The results suggest that the visual system has a stereoscopic detector that responds to stimuli that meet a long-distance requirement for the perception of partially occluding surfaces.
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Affiliation(s)
- Hiroyuki Mitsudo
- ATR Human Information Science Laboratories, 2-2-2 Hikaridai, Soraku-gun, Kyoto 6190288, Japan.
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Tanabe S, Doi T, Umeda K, Fujita I. Disparity-Tuning Characteristics of Neuronal Responses to Dynamic Random-Dot Stereograms in Macaque Visual Area V4. J Neurophysiol 2005; 94:2683-99. [PMID: 16000525 DOI: 10.1152/jn.00319.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stereo processing begins in the striate cortex and involves several extrastriate visual areas. We quantitatively analyzed the disparity-tuning characteristics of neurons in area V4 of awake, fixating monkeys. Approximately half of the analyzed V4 cells were tuned for horizontal binocular disparities embedded in dynamic random-dot stereograms (RDSs). Their response preferences were strongly biased for crossed disparities. To characterize the disparity-tuning profile, we fitted a Gabor function to the disparity-tuning data. The distribution of V4 cells showed a single dense cluster in a joint parameter space of the center and the phase parameters of the fitted Gabor function; most V4 neurons were maximally sensitive to fine stereoscopic depth increments near zero disparity. Comparing single-cell responses with background multiunit responses at the same sites showed that disparity-sensitive cells were clustered within V4 and that nearby cells possessed similar preferred disparities. Consistent with a recent report by Hegdé and Van Essen, the disparity tuning for an RDS drastically differed from that for a solid-figure stereogram (SFS). Disparity-tuning curves were generally broader for SFSs than for RDSs, and there was no correlation between the fitted Gabor functions' amplitudes, widths, or peaks for the two types of stereograms. The differences were partially attributable to shifts in the monocular images of an SFS. Our results suggest that the representation of stereoscopic depth in V4 is suited for detecting fine structural features protruding from a background. The representation is not generic and differs when the stimulus is broad-band noise or a solid figure.
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Affiliation(s)
- Seiji Tanabe
- Laboratory for Cognitive Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Japan
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Cisarik PM, Harwerth RS. Stereoscopic depth magnitude estimation: effects of stimulus spatial frequency and eccentricity. Behav Brain Res 2005; 160:88-98. [PMID: 15836903 DOI: 10.1016/j.bbr.2004.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 11/10/2004] [Accepted: 11/15/2004] [Indexed: 11/25/2022]
Abstract
To determine the effects of stimulus spatial frequency and retinal eccentricity on the perception of depth magnitude derived from disparity cues alone, subjects were asked to estimate the magnitude of depth of a stereoscopically viewed Gabor patch presented to the central or peripheral field with either crossed or uncrossed absolute disparity. Disparity vergence responses to the same Gabor stimuli were separately estimated subjectively by determining the offset required for dichoptic nonius alignment following presentation of the stimulus. The normalized stereoscopic magnitude estimation data generally showed that crossed disparities were perceived with greater depth than uncrossed disparities of the same magnitude, whether presented to the central or peripheral field. Asymmetries in magnitude of depth perception ranged from mild differences between depth directions to complete lack of depth perception for one direction. Disparity vergence response functions varied from (1) appropriate initiation of vergence to both directions of disparity, (2) initiation of vergence to only one direction of disparity, or (3) an attenuated initiation of vergence response to either direction of disparity. Within subjects, their asymmetries in magnitude of depth perception did not correlate with their asymmetries in vergence initiation. The similarity of the asymmetric depth magnitude estimation for a given individual at both stimulus locations tested suggests that common neural mechanisms are responsible for central and peripheral depth magnitude estimation. The lack of correlation between the perceptual and motor responses to the same stimuli suggests that the neural pathways for these responses diverge shortly after the detection of disparity in primary visual cortex.
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Affiliation(s)
- Patricia M Cisarik
- University of Houston, College of Optometry, 505 J. Davis Armistead Building, Houston, TX 77004-2020, USA.
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Mitsudo H, Nakamizo S, Ono H. Greater depth seen with phantom stereopsis is coded at the early stages of visual processing. Vision Res 2005; 45:1365-74. [PMID: 15743607 DOI: 10.1016/j.visres.2004.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 12/08/2004] [Accepted: 12/08/2004] [Indexed: 11/22/2022]
Abstract
A visual search task was used to investigate the spatially parallel coding of depth from binocular disparity and from binocularly unmatched features. Experiment 1, using disparity noise, showed that detectability is higher for illusory phantom targets defined by unmatched features than for disparity-defined targets, although the two targets were equated as to theoretically minimum depth. Experiment 2, using binocularly unmatched noise whose width was equal to the disparity of the noise used in Experiment 1, showed that noise severely interferes with the detection of both the disparity and the phantom targets. These results are consistent with the idea that the greater depth seen with phantom stereopsis is coded at the early stages of visual processing.
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Affiliation(s)
- Hiroyuki Mitsudo
- Centre for Vision Research, York University, 4700 Keele Street, Toronto, Ont., Canada M3J 1P3.
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22
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van Ee R. Correlation between stereoanomaly and perceived depth when disparity and motion interact in binocular matching. Perception 2003; 32:67-84. [PMID: 12613787 DOI: 10.1068/p3459] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of this study was to find out to what extent binocular matching is facilitated by motion when stereoanomalous and normal subjects estimate the perceived depth of a 3-D stimulus containing excessive matching candidates. Thirty subjects viewed stimuli that consisted of bars uniformly distributed inside a volume. They judged the perceived depth-to-width ratio of the volume by adjusting the aspect ratio of an outline rectangle (a metrical 3-D task). Although there were large inter-subject differences in the depth perceived, the experimental results yielded a good correlation with stereoanomaly (the inability to distinguish disparities of different magnitudes and/or signs in part of the disparity spectrum). The results cannot be explained solely by depth-cue combination. Since up to 30% of the population is stereoanomalous, stereoscopic experiments would yield more informative results if subjects were first characterized with regard to their stereo capacities. Intriguingly, it was found that motion does not help to define disparities in subjects who are able to perceive depth-from-disparity in half of the disparity spectrum. These stereoanomalous subjects were found to rely completely on the motion signals. This suggests that the perception of volumetric depth in subjects with normal stereoscopic vision requires the joint processing of crossed and uncrossed disparities.
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Affiliation(s)
- Raymond van Ee
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, NE 20-451, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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Abstract
An important goal of the visual system is the segmentation of image features into objects and their backgrounds. A primary cue for this is motion: when a region shares the same pattern of motion it is segregated from its surround. Three experiments were carried out to investigate whether the segmentation of image features on the basis of motion information is facilitated by the addition of binocular disparity. Coherence thresholds were measured for the discrimination of the global direction of motion of random dot kinematograms (RDKs) in which the relative disparity of the signal and noise dots was manipulated. When the signal dots were embedded in a three dimensional cloud of noise dots, coherence thresholds were similar to those measured when signal and noise dots were both presented with zero disparity. However, when the signal dots were separated from the noise dots in depth, global motion processing was strongly facilitated. These results were considered in terms of two models, one in which global motion is processed by disparity tuned mechanisms, the other in which the discrimination of the direction of motion is mediated by an attention-based system. It was concluded that global motion processing is not tuned for binocular disparity and that the facilitation of the discrimination of direction provided by binocular disparity in certain circumstances reflects the rôle of an attention-based system.
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Affiliation(s)
- P B Hibbard
- Department of Psychology, University of Surrey, Guildford, UK.
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Becker S, Bowd C, Shorter S, King K, Patterson R. Occlusion contributes to temporal processing differences between crossed and uncrossed stereopsis in random-dot displays. Vision Res 1999; 39:331-9. [PMID: 10326139 DOI: 10.1016/s0042-6989(98)00110-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Stereoscopic depth discrimination was investigated in crossed and uncrossed directions using stimuli defined by binocular disparity differences embedded in dynamic random-dot stereograms. Across three experiments, fixation was directed to a point on the display screen (which placed crossed stimuli in front of and uncrossed stimuli behind, the background dots of the stereogram), to a point in front of the display screen (which placed both crossed and uncrossed stimuli in front of the background dots), and to a point behind the display screen (which placed both crossed and uncrossed stimuli behind the background dots). Results showed that depth discrimination was always good when the stimuli appeared in front of the background dots of the stereogram, whereas discrimination was always poor when the stimuli appeared behind the background dots. These results suggest that differences between crossed and uncrossed stereopsis as reported in past research arose, in part, from effects related to occlusion.
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Affiliation(s)
- S Becker
- Department of Psychology, Washington State University, Pullman 99164-4820, USA
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