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Llamas-Cornejo I, Peterzell DH, Serrano-Pedraza I. Temporal mechanisms in frontoparallel stereomotion revealed by individual differences analysis. Eur J Neurosci 2024; 59:3117-3133. [PMID: 38622053 DOI: 10.1111/ejn.16342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/17/2024]
Abstract
Masking experiments, using vertical and horizontal sinusoidal depth corrugations, have suggested the existence of more than two spatial-frequency disparity mechanisms. This result was confirmed through an individual differences approach. Here, using factor analytic techniques, we want to investigate the existence of independent temporal mechanisms in frontoparallel stereoscopic (cyclopean) motion. To construct stereomotion, we used sinusoidal depth corrugations obtained with dynamic random-dot stereograms. Thus, no luminance motion was present monocularly. We measured disparity thresholds for drifting vertical (up-down) and horizontal (left-right) sinusoidal corrugations of 0.4 cyc/deg at 0.25, 0.5, 1, 2, 4, 6, and 8 Hz. In total, we tested 34 participants. Results showed a small orientation anisotropy with lower thresholds for horizontal corrugations. Disparity thresholds as a function of temporal frequency were almost constant from 0.25 up to 1 Hz, and then they increased monotonically. Principal component analysis uncovered two significant factors for vertical and two for horizontal corrugations. Varimax rotation showed that one factor loaded from 0.25 to 1-2 Hz and a second factor from 2 to 4 to 8 Hz. Direct Oblimin rotation indicated a moderate intercorrelation of both factors. Our results suggest the possible existence of two somewhat interdependent temporal mechanisms involved in frontoparallel stereomotion.
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Affiliation(s)
- Ichasus Llamas-Cornejo
- Department of Experimental Psychology, Faculty of Psychology, Universidad Complutense de Madrid, Campus de Somosaguas, Madrid, Spain
| | - David H Peterzell
- Fielding Graduate University, Santa Barbara, California, and National University (JFK), Pleasant Hill, California, USA
| | - Ignacio Serrano-Pedraza
- Department of Experimental Psychology, Faculty of Psychology, Universidad Complutense de Madrid, Campus de Somosaguas, Madrid, Spain
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2
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Aguilera-Francisco A, Serrano-Pedraza I. The Stereoscopic Anisotropy Is Smaller in Elderly Population. Invest Ophthalmol Vis Sci 2022; 63:26. [DOI: 10.1167/iovs.63.12.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Aracelis Aguilera-Francisco
- Department of Experimental Psychology, Faculty of Psychology, Universidad Complutense de Madrid, Campus de Somosaguas, Madrid, Spain
| | - Ignacio Serrano-Pedraza
- Department of Experimental Psychology, Faculty of Psychology, Universidad Complutense de Madrid, Campus de Somosaguas, Madrid, Spain
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Chopin A, Silver MA, Sheynin Y, Ding J, Levi DM. Transfer of Perceptual Learning From Local Stereopsis to Global Stereopsis in Adults With Amblyopia: A Preliminary Study. Front Neurosci 2021; 15:719120. [PMID: 34630011 PMCID: PMC8498040 DOI: 10.3389/fnins.2021.719120] [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: 06/01/2021] [Accepted: 09/02/2021] [Indexed: 11/18/2022] Open
Abstract
It has long been debated whether the analysis of global and local stereoscopic depth is performed by a single system or by separate systems. Global stereopsis requires the visual system to solve a complex binocular matching problem to obtain a coherent percept of depth. In contrast, local stereopsis requires only a simple matching of similar image features. In this preliminary study, we recruited five adults with amblyopia who lacked global stereopsis and trained them on a computerized local stereopsis depth task for an average of 12 h. Three out of five (60%) participants recovered fine global stereoscopic vision through training. Those who recovered global stereopsis reached a learning plateau more quickly on the local stereopsis task, and they tended to start the training with better initial local stereopsis performance, to improve more on local stereopsis with training, and to have less severe amblyopia. The transfer of learning from local stereopsis to global stereopsis is compatible with an interacting two-stage model.
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Affiliation(s)
- Adrien Chopin
- School of Optometry, University of California, Berkeley, Berkeley, CA, United States.,Département d'Etudes Cognitives, Ecole Normale Supérieure, Paris, France.,Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Michael A Silver
- School of Optometry, University of California, Berkeley, Berkeley, CA, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States.,Vision Science Graduate Group, University of California, Berkeley, Berkeley, CA, United States
| | - Yasha Sheynin
- School of Optometry, University of California, Berkeley, Berkeley, CA, United States.,McGill Vision Research Unit, McGill University, Montréal, QC, Canada
| | - Jian Ding
- School of Optometry, University of California, Berkeley, Berkeley, CA, United States
| | - Dennis Michael Levi
- School of Optometry, University of California, Berkeley, Berkeley, CA, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States.,Vision Science Graduate Group, University of California, Berkeley, Berkeley, CA, United States
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Garcia-Valle G, Arranz-Paraiso S, Serrano-Pedraza I, Ferre M. Estimation of Torso Vibrotactile Thresholds Using Eccentric Rotating Mass Motors. IEEE TRANSACTIONS ON HAPTICS 2021; 14:538-550. [PMID: 33378262 DOI: 10.1109/toh.2020.3048290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The characterization of vibrotactile perception is crucial to accurately configure haptic devices and create appropriate stimuli for improving user performance in human-machine interaction systems. This article presents a study aiming to determine the absolute and differential vibrotactile thresholds in different areas of the torso to develop reliable haptic patterns to be displayed using a haptic vest. In the 'absolute threshold' experiment, we measure the minimum detectable vibration using a forced-choice task. Furthermore, in the 'differential threshold' experiment, we measure the minimum frequency change needed for users to discriminate two successive vibrotactile stimuli using a vibration matching task. The first experiment does not show differences between absolute thresholds, opening up the possibility of setting a unique minimal vibration for creating haptic patterns. Similarly, the second experiment does not show differences between differential thresholds. Moreover, as these thresholds follow Weber's law, it is viable to estimate any upper or lower differential threshold for any reference stimulus using a K-value. These results are a first step for creating vibrotactile patterns over the torso with the employed eccentric rotating mass motors. Moreover, the whole study provides a method to obtain these psychophysical values since the usage of different motors can change these results.
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Serrano-Pedraza I, Vancleef K, Herbert W, Goodship N, Woodhouse M, Read JCA. Efficient estimation of stereo thresholds: What slope should be assumed for the psychometric function? PLoS One 2020; 15:e0226822. [PMID: 31895925 PMCID: PMC6939937 DOI: 10.1371/journal.pone.0226822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/04/2019] [Indexed: 11/21/2022] Open
Abstract
Bayesian staircases are widely used in psychophysics to estimate detection thresholds. Simulations have revealed the importance of the parameters selected for the assumed subject’s psychometric function in enabling thresholds to be estimated with small bias and high precision. One important parameter is the slope of the psychometric function, or equivalently its spread. This is often held fixed, rather than estimated for individual subjects, because much larger numbers of trials are required to estimate the spread as well as the threshold. However, if this fixed value is wrong, the threshold estimate can be biased. Here we determine the optimal slope to minimize bias and maximize precision when measuring stereoacuity with Bayesian staircases. We performed 2- and 4AFC disparity detection stereo experiments in order to measure the spread of the disparity psychometric function in human observers assuming a Logistic function. We found a wide range, between 0.03 and 3.5 log10 arcsec, with little change with age. We then ran simulations to examine the optimal spread using the empirical data. From our simulations and for three different experiments, we recommend selecting assumed spread values between the percentiles 60–80% of the population distribution of spreads (these percentiles can be extended to other type of thresholds). For stereo thresholds, we recommend a spread around the value σ = 1.7 log10 arcsec for 2AFC (slope β = 4.3 /log10 arcsec), and around σ = 1.5 log10 arcsec for 4AFC (β = 4.9 /log10 arcsec). Finally, we compared a Bayesian procedure (ZEST using the optimal σ) with five Bayesian procedures that are versions of ZEST-2D, Psi, and Psi-marginal. In general, for the conditions tested, ZEST optimal σ showed the lowest threshold bias and highest precision.
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Affiliation(s)
- Ignacio Serrano-Pedraza
- Faculty of Psychology, Universidad Complutense de Madrid, Madrid, Spain
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
| | - Kathleen Vancleef
- Cognitive Neuropsychology Centre, Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - William Herbert
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nicola Goodship
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Maeve Woodhouse
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jenny C. A. Read
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
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Read JCA, Rafiq S, Hugill J, Casanova T, Black C, O’Neill A, Puyat V, Haggerty H, Smart K, Powell C, Taylor K, Clarke MP, Vancleef K. Characterizing the Randot Preschool stereotest: Testability, norms, reliability, specificity and sensitivity in children aged 2-11 years. PLoS One 2019; 14:e0224402. [PMID: 31697704 PMCID: PMC6837395 DOI: 10.1371/journal.pone.0224402] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 10/11/2019] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To comprehensively assess the Randot Preschool stereo test in young children, including testability, normative values, test/retest reliability and sensitivity and specificity for detecting binocular vision disorders. METHODS We tested 1005 children aged 2-11 years with the Randot Preschool stereo test, plus a cover/uncover test to detect heterotropia. Monocular visual acuity was assessed in both eyes using Keeler Crowded LogMAR visual acuity test for children aged 4 and over. RESULTS Testability was very high: 65% in two-year-olds, 92% in three-year-olds and ~100% in older children. Normative values: In 389 children aged 2-5 with apparently normal vision, 6% of children scored nil (stereoblind). In those who obtained a threshold, the mean log threshold was 2.06 log10 arcsec, corresponding to 114 arcsec, and the median threshold was 100 arcsec. Most older children score 40 arcsec, the best available score. We found a small sex difference, with girls scoring slightly but significantly better. Test/retest reliability: ~99% for obtaining any score vs nil. Agreement between stereo thresholds is poor in children aged 2-5; 95% limit of agreement = 0.7 log10 arcsec: five-fold change in stereo threshold may occur without any change in vision. In children over 5, the test essentially acts only as a binary classifier since almost all non-stereoblind children score 40 arcsec. Specificity (true negative rate): >95%. Sensitivity (true positive rate): poor, <50%, i.e. around half of children with a demonstrable binocular vision abnormality score well on the Randot Preschool. CONCLUSIONS The Randot Preschool is extremely accessible for even very young children, and is very reliable at classifying children into those who have any stereo vision vs those who are stereoblind. However, its ability to quantify stereo vision is limited by poor repeatability in children aged 5 and under, and a very limited range of scores relevant to children aged over 5.
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Affiliation(s)
- Jenny C. A. Read
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Sheima Rafiq
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Jess Hugill
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Therese Casanova
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Carla Black
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Adam O’Neill
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Vicente Puyat
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
| | - Helen Haggerty
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, England, United Kingdom
| | - Kathryn Smart
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, England, United Kingdom
| | - Christine Powell
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, England, United Kingdom
| | - Kate Taylor
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, England, United Kingdom
| | - Michael P. Clarke
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, England, United Kingdom
| | - Kathleen Vancleef
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, England, United Kingdom
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7
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Assessment of stereovision with digital testing in adults and children with normal and impaired binocularity. Vision Res 2019; 164:69-82. [DOI: 10.1016/j.visres.2019.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 07/10/2019] [Accepted: 07/24/2019] [Indexed: 11/20/2022]
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Vancleef K, Serrano-Pedraza I, Sharp C, Slack G, Black C, Casanova T, Hugill J, Rafiq S, Burridge J, Puyat V, Enongue JE, Gale H, Akotei H, Collier Z, Haggerty H, Smart K, Powell C, Taylor K, Clarke MP, Morgan G, Read JCA. ASTEROID: A New Clinical Stereotest on an Autostereo 3D Tablet. Transl Vis Sci Technol 2019; 8:25. [PMID: 30834173 PMCID: PMC6396686 DOI: 10.1167/tvst.8.1.25] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/20/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose To describe a new stereotest in the form of a game on an autostereoscopic tablet computer designed to be suitable for use in the eye clinic and present data on its reliability and the distribution of stereo thresholds in adults. Methods Test stimuli were four dynamic random-dot stereograms, one of which contained a disparate target. Feedback was given after each trial presentation. A Bayesian adaptive staircase adjusted target disparity. Threshold was estimated from the mean of the posterior distribution after 20 responses. Viewing distance was monitored via a forehead sticker viewed by the tablet's front camera, and screen parallax was adjusted dynamically so as to achieve the desired retinal disparity. Results The tablet must be viewed at a distance of greater than ∼35 cm to produce a good depth percept. Log thresholds were roughly normally distributed with a mean of 1.75 log10 arcsec = 56 arcsec and SD of 0.34 log10 arcsec = a factor of 2.2. The standard deviation agrees with previous studies, but ASTEROID thresholds are approximately 1.5 times higher than a similar stereotest on stereoscopic 3D TV or on Randot Preschool stereotests. Pearson correlation between successive tests in same observer was 0.80. Bland-Altman 95% limits of reliability were ±0.64 log10 arcsec = a factor of 4.3, corresponding to an SD of 0.32 log10 arcsec on individual threshold estimates. This is similar to other stereotests and close to the statistical limit for 20 responses. Conclusions ASTEROID is reliable, easy, and portable and thus well-suited for clinical stereoacuity measurements. Translational Relevance New 3D digital technology means that research-quality psychophysical measurement of stereoacuity is now feasible in the clinic.
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Affiliation(s)
- Kathleen Vancleef
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Ignacio Serrano-Pedraza
- Facultad de Psicología, Universidad Complutense de Madrid, Campus de Somosaguas, Madrid, Spain
| | - Craig Sharp
- School of Computing, Newcastle University, 1 Science Square, Newcastle upon Tyne, UK
| | - Gareth Slack
- School of Computing, Newcastle University, 1 Science Square, Newcastle upon Tyne, UK
| | - Carla Black
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Therese Casanova
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Jess Hugill
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Sheima Rafiq
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - James Burridge
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Vito Puyat
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Josee Ewane Enongue
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Henry Gale
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Hannah Akotei
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Zoe Collier
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
| | - Helen Haggerty
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Queen Victoria Road, Newcastle upon Tyne, UK
| | - Kathryn Smart
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Queen Victoria Road, Newcastle upon Tyne, UK
| | - Christine Powell
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Queen Victoria Road, Newcastle upon Tyne, UK
| | - Kate Taylor
- Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Queen Victoria Road, Newcastle upon Tyne, UK
| | - Michael P Clarke
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.,Newcastle Eye Centre, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Trust, Queen Victoria Road, Newcastle upon Tyne, UK
| | - Graham Morgan
- School of Computing, Newcastle University, 1 Science Square, Newcastle upon Tyne, UK
| | - Jenny C A Read
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
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Vancleef K, Read JCA, Herbert W, Goodship N, Woodhouse M, Serrano-Pedraza I. Two choices good, four choices better: For measuring stereoacuity in children, a four-alternative forced-choice paradigm is more efficient than two. PLoS One 2018; 13:e0201366. [PMID: 30059524 PMCID: PMC6066230 DOI: 10.1371/journal.pone.0201366] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/13/2018] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Measuring accurate thresholds in children can be challenging. A typical psychophysical experiment is usually too long to keep children engaged. However, a reduction in the number of trials decreases the precision of the threshold estimate. We evaluated the efficiency of forced-choice paradigms with 2 or 4 alternatives (2-AFC, 4-AFC) in a disparity detection experiment. 4-AFC paradigms are statistically more efficient, but also more cognitively demanding, which might offset their theoretical advantage in young children. METHODS We ran simulations evaluating bias and precision of threshold estimates of 2-AFC and 4-AFC paradigms. In addition, we measured disparity thresholds in 43 children (aged 6 to 17 years) with a 4-AFC paradigm and in 49 children (aged 4 to 17 years) with a 2-AFC paradigm, both using an adaptive weighted one-up one-down staircase. RESULTS Simulations indicated a similar bias and precision for a 2-AFC paradigm with double the number of trials as a 4-AFC paradigm. On average, estimated threshold of the simulated data was equal to the model threshold, indicating no bias. The precision was improved with an increasing number of trials. Likewise, our data showed a similar bias and precision for a 2-AFC paradigm with 60 trials as for a 4-AFC paradigm with 30 trials. Trials in the 4-AFC paradigm took slightly longer as participants scanned more alternatives. However, the 4-AFC task still ended up faster for a given precision. CONCLUSION Bias and precision were similar in a 4-AFC task compared to a 2-AFC task with double the number of trials. However, a 4-AFC paradigm was more time efficient and is therefore recommended.
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Affiliation(s)
- Kathleen Vancleef
- Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, United Kingdom
- * E-mail:
| | - Jenny C. A. Read
- Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - William Herbert
- Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Nicola Goodship
- Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Maeve Woodhouse
- Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne, United Kingdom
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Peterzell DH, Serrano-Pedraza I, Widdall M, Read JCA. Thresholds for sine-wave corrugations defined by binocular disparity in random dot stereograms: Factor analysis of individual differences reveals two stereoscopic mechanisms tuned for spatial frequency. Vision Res 2017; 141:127-135. [PMID: 29155009 DOI: 10.1016/j.visres.2017.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 11/02/2017] [Accepted: 11/13/2017] [Indexed: 01/05/2023]
Abstract
Threshold functions for sinusoidal depth corrugations typically reach their minimum (highest sensitivity) at spatial frequencies of 0.2-0.4 cycles/degree (cpd), with lower thresholds for horizontal than vertical corrugations at low spatial frequencies. To elucidate spatial frequency and orientation tuning of stereoscopic mechanisms, we measured the disparity sensitivity functions, and used factor analytic techniques to estimate the existence of independent underlying stereo channels. The data set (N = 30 individuals) was for horizontal and vertical corrugations of spatial frequencies ranging from 0.1 to 1.6 cpd. A principal component analysis of disparity sensitivities (log-arcsec) revealed that two significant factors accounted for 70% of the variability. Following Varimax rotation to approximate "simple structure", one factor clearly loaded onto low spatial frequencies (≤0.4 cpd), and a second was tuned to higher spatial frequencies (≥0.8 cpd). Each factor had nearly identical tuning (loadings) for horizontal and vertical patterns. The finding of separate factors for low and high spatial frequencies is consistent with previous studies. The failure to find separate factors for horizontal and vertical corrugations is somewhat surprising because the neuronal mechanisms are believed to be different. Following an oblique rotation (Direct Oblimin), the two factors correlated significantly, suggesting some interdependence rather than full independence between the two factors.
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Affiliation(s)
- David H Peterzell
- College of Psychology, John F. Kennedy University, Pleasant Hill, CA, USA.
| | | | - Michael Widdall
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Jenny C A Read
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
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11
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Vancleef K, Read JCA, Herbert W, Goodship N, Woodhouse M, Serrano‐Pedraza I. Overestimation of stereo thresholds by the TNO stereotest is not due to global stereopsis. Ophthalmic Physiol Opt 2017; 37:507-520. [PMID: 28337792 PMCID: PMC5516234 DOI: 10.1111/opo.12371] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/09/2017] [Indexed: 11/29/2022]
Abstract
PURPOSE It has been repeatedly shown that the TNO stereotest overestimates stereo threshold compared to other clinical stereotests. In the current study, we test whether this overestimation can be attributed to a distinction between 'global' (or 'cyclopean') and 'local' (feature or contour-based) stereopsis. METHODS We compared stereo thresholds of a global (TNO) and a local clinical stereotest (Randot Circles). In addition, a global and a local psychophysical stereotest were added to the design. One hundred and forty-nine children between 4 and 16 years old were included in the study. RESULTS Stereo threshold estimates with TNO were a factor of two higher than with any of the other stereotests. No significant differences were found between the other tests. Bland-Altman analyses also indicated low agreement between TNO and the other stereotests, especially for higher stereo threshold estimates. Simulations indicated that the TNO test protocol and test disparities can account for part of this effect. DISCUSSION The results indicate that the global - local distinction is an unlikely explanation for the overestimated thresholds of TNO. Test protocol and disparities are one contributing factor. Potential additional factors include the nature of the task (TNO requires depth discrimination rather than detection) and the use of anaglyph red/green 3D glasses rather than polarizing filters, which may reduce binocular fusion.
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Affiliation(s)
| | - Jenny C. A. Read
- Institute of NeuroscienceNewcastle UniversityNewcastle‐upon‐TyneUK
| | - William Herbert
- Institute of NeuroscienceNewcastle UniversityNewcastle‐upon‐TyneUK
| | - Nicola Goodship
- Institute of NeuroscienceNewcastle UniversityNewcastle‐upon‐TyneUK
| | - Maeve Woodhouse
- Institute of NeuroscienceNewcastle UniversityNewcastle‐upon‐TyneUK
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12
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Serrano-Pedraza I, Vancleef K, Read JCA. Avoiding monocular artifacts in clinical stereotests presented on column-interleaved digital stereoscopic displays. J Vis 2017; 16:13. [PMID: 27846341 PMCID: PMC5114011 DOI: 10.1167/16.14.13] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
New forms of stereoscopic 3-D technology offer vision scientists new opportunities for research, but also come with distinct problems. Here we consider autostereo displays where the two eyes' images are spatially interleaved in alternating columns of pixels and no glasses or special optics are required. Column-interleaved displays produce an excellent stereoscopic effect, but subtle changes in the angle of view can increase cross talk or even interchange the left and right eyes' images. This creates several challenges to the presentation of cyclopean stereograms (containing structure which is only detectable by binocular vision). We discuss the potential artifacts, including one that is unique to column-interleaved displays, whereby scene elements such as dots in a random-dot stereogram appear wider or narrower depending on the sign of their disparity. We derive an algorithm for creating stimuli which are free from this artifact. We show that this and other artifacts can be avoided by (a) using a task which is robust to disparity-sign inversion—for example, a disparity-detection rather than discrimination task—(b) using our proposed algorithm to ensure that parallax is applied symmetrically on the column-interleaved display, and (c) using a dynamic stimulus to avoid monocular artifacts from motion parallax. In order to test our recommendations, we performed two experiments using a stereoacuity task implemented with a parallax-barrier tablet. Our results confirm that these recommendations eliminate the artifacts. We believe that these recommendations will be useful to vision scientists interested in running stereo psychophysics experiments using parallax-barrier and other column-interleaved digital displays.
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Affiliation(s)
- Ignacio Serrano-Pedraza
- Faculty of Psychology, Universidad Complutense de Madrid, Madrid, ://www.researchgate.net/profile/Ignacio_Serrano-Pedraza
| | - Kathleen Vancleef
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne,
| | - Jenny C A Read
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, ://www.jennyreadresearch.com/
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