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Attention, Perception & Psychophysics Aug 2021The hypothesis that perspective foreshortening leads to errors in the visual perception of angles, was tested in four experiments. An oblique to a z-dimension line was...
The hypothesis that perspective foreshortening leads to errors in the visual perception of angles, was tested in four experiments. An oblique to a z-dimension line was presented (a) on the ground in Experiments 1 and 2, and (b) on a wall in Experiments 3 and 4. Observers judged the acute angle between the oblique and the z-line. Foreshortening increased with the oblique's distance along the z-line and, in Experiments 2 and 4, shorter distances from the eye to the ground or wall. As distance and eye-height vary, so does the target's slant to the line of sight. We argue the apparent angles between the lines increased with foreshortening because vision underestimates the fast rate of foreshortening with elevation compared with the slower rates in azimuth.
Topics: Depth Perception; Distance Perception; Humans; Visual Perception
PubMed: 33904152
DOI: 10.3758/s13414-021-02299-w -
Journal of Vision Nov 2021When an object casts a shadow on a background surface, both the offset of the shadow and the blur of its penumbra are potential cues to the distance between the object...
When an object casts a shadow on a background surface, both the offset of the shadow and the blur of its penumbra are potential cues to the distance between the object and the background. However, the shadow offset and blur are also affected by the direction and angular extent of the light source and these are often unknown. This means that the observer must make some assumptions about the illumination, the expected distribution of depth, or the relation between offset and depth in order to use shadows to make distance judgments. Here, we measure human judgments of perceived depth over a range of shadow offsets, blurs, and lighting directions to gain insight into this internal model. We find that distance judgments are relatively unaffected by blur or light direction, whereas the shadow offset has a strong and linear effect. The data are consistent with two models, a generic shadow-to-depth model and a Bayesian model.
Topics: Bayes Theorem; Cues; Depth Perception; Humans; Lighting; Photic Stimulation
PubMed: 34842901
DOI: 10.1167/jov.21.12.15 -
BMC Ophthalmology Dec 2021To evaluate depth perception in Primary open angle glaucoma (POAG), glaucoma suspects compared to controls and to determine the association between depth perception and...
BACKGROUND
To evaluate depth perception in Primary open angle glaucoma (POAG), glaucoma suspects compared to controls and to determine the association between depth perception and severity of glaucoma.
METHODS
This was a hospital based, comparative, cross-sectional study. The ethical clearance was taken from institutional review committee of Institute of Medicine [Reference no.399 (6-11) E 077-078]. Agematched, equal number of participants in each group (N=20) were evaluated with both Titmus and Frisby stereoacuity tests to measure depth perception as stereopsis threshold in seconds of arc. The participants were selected using the purposive sampling technique.
RESULTS
There was no differences in age, sex, or best corrected visual acuity, intraocular pressure, central corneal thickness (CCT), found among the three groups (POAG, Glaucoma Suspects and Control) respectively. However, there was significant difference in cup disc ratio (CDR) between the groups. Equal number of male and female were there in each group, while in POAG group male to female ratio was 3:2. The mean stereoacuity threshold in control group was 53.5±23.23 seconds of arc with Titmus test and 38.75±18.83 seconds of arc with Frisby stereoacuity test. The difference in threshold was significant between control and glaucoma suspect with Titmus (t=1.991, p=0.05) and with Frisby (t=2.114, p=0.04). The difference was also significant in POAG group by Titmus (t=3.135, p=0.0033) and by Frisby (t=3.014, p=0.004). More so, with increasing severity of glaucoma, the mean threshold of stereopsis increased as seen with both Titmus and Frisby Tests (ANOVA, p < 0.001) CONCLUSION: Primary open angle glaucoma patients and glaucoma suspects, showed significant reduction in depth perception. Decreased stereoacuity was associated with greater glaucomatous visual field loss.
Topics: Cross-Sectional Studies; Depth Perception; Female; Glaucoma; Glaucoma, Open-Angle; Humans; Intraocular Pressure; Male; Visual Field Tests
PubMed: 34911486
DOI: 10.1186/s12886-021-02198-6 -
Investigative Ophthalmology & Visual... Jan 2022We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction.
PURPOSE
We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction.
METHODS
In this study, we quantified normal adults' static and dynamic (i.e., laterally moving) stereoscopic performance using a psychophysical task, where we dichoptically presented randomly arranged, limited lifetime Gabor elements at two depth planes (one plane was at the fixation plane and the other at an uncrossed disparity relative to the fixation plane). Each plane contained half of the elements. For the dynamic condition, all elements were vertically oriented and moved to the left in one plane and to the right in another plane; for the static condition, the elements were horizontally oriented in one plane and vertically oriented in another plane.
RESULTS
For the range of motion speed that we measured (from 0.17°/s to 5.33°/s), we observed clear speed tuning of the stereo sensitivity (P = 3.0 × 10-5). The shape of this tuning did not significantly change with different spatial frequencies. We also found a significant difference in stereo sensitivity between stereopsis with static and laterally moving stimuli (speed = 0.67°/s; P = 0.004). Such difference was not evident when we matched the task between the static and moving stimuli.
CONCLUSIONS
We report that lateral motion modulates human global depth perception. This motion/stereo constraint is related to motion velocity not stimulus temporal frequency. We speculate that the processing of motion-based stereopsis of the kind reported here occurs in dorsal extrastriate cortex.
Topics: Adult; Depth Perception; Female; Humans; Male; Motion Perception; Psychophysics; Reference Values; Vision Disparity; Vision, Binocular; Visual Cortex; Young Adult
PubMed: 35077551
DOI: 10.1167/iovs.63.1.32 -
Vision Research Mar 2021We describe a new unified model to explain both binocular fusion and depth perception, over a broad range of depths. At each location, the model consists of an array of...
We describe a new unified model to explain both binocular fusion and depth perception, over a broad range of depths. At each location, the model consists of an array of paired spatial frequency filters, with different relative horizontal shifts (position disparity) and interocular phase disparities of 0, 90, ±180, or -90°. The paired filters with different spatial profiles (non-zero phase disparity) compute interocular misalignment and provide phase-disparity energy (binocular fusion energy) to drive selection of the appropriate filters along the position disparity space until the misalignment is eliminated and sensory fusion is achieved locally. The paired filters with identical spatial profiles (0 phase disparity) compute the position-disparity energy. After sensory fusion, the combination of position and possible residual phase disparity energies is calculated for binocular depth perception. Binocular fusion occurs at multiple scales following a coarse-to-fine process. At a given location, the apparent depth is the weighted sum of fusion shifts combined with residual phase disparity in all spatial-frequency channels, and the weights depend on stimulus spatial frequency and stimulus contrast. To test the theory, we measured disparity minimum and maximum thresholds (Dmin and Dmax) at three spatial frequencies and with different intraocular contrast levels. The stimuli were Random-Gabor-Patch (RGP) stereograms consisting of Gabor patches with random positions and phases, but with a fixed spatial frequency. The two eyes viewed identical arrays of patches except that one eye's array could be shifted horizontally and could differ in contrast. Our experiments and modeling reveal two contrast normalization mechanisms: (1) Energy Normalization (EN): Binocular energy is normalized with monocular energy after the site of binocular combination. This predicts constant Dmin thresholds when varying stimulus contrast in the two eyes; (2) DSKL model Interocular interactions: Monocular contrasts are normalized before the binocular combination site through interocular contrast gain-control and gain-enhancement mechanisms. This predicts contrast dependent Dmax thresholds. We tested a range of models and found that a model consisting of a second-order pathway with DSKL interocular interactions and a first-order pathway with EN at each spatial-frequency band can account for both the Dmin and Dmax data very well. Simulations show that the model makes reasonable predictions of suprathreshold depth perception.
Topics: Contrast Sensitivity; Depth Perception; Humans; Vision Disparity; Vision, Binocular
PubMed: 33359897
DOI: 10.1016/j.visres.2020.11.009 -
Psychonomic Bulletin & Review Apr 2022Humans constantly use depth information to support perceptual decisions about object size and location in space, as well as planning and executing actions. It was...
Humans constantly use depth information to support perceptual decisions about object size and location in space, as well as planning and executing actions. It was recently reported that perceived depth modulates perceptual performance even when depth information is not relevant to the task, with faster shape discrimination for objects perceived as being close to the observer. However, it is yet to be determined if the observed "close advantage" reflects differences in psychophysical sensitivity or response bias. Moreover, it is unclear whether this advantage is generalizable to other viewing situations and tasks. To address these outstanding issues, we evaluated whether visual resolution is modulated by perceived depth defined by 2D pictorial cues. In a series of experiments, we used the method of constant stimuli to measure the precision of perceptual judgements for stimuli positioned at close, far, and flat perceived distances. In Experiment 1, we found that size discrimination was more precise when the object was perceived to be closer to the observers. Experiments 2a and 2b extended this finding to a visual property orthogonal to depth information, by showing superior orientation discrimination for "close" objects. Finally, Experiment 3 demonstrated that the close advantage also occurs when performing high-level perceptual tasks such as face perception. Taken together, our results provide novel evidence that the perceived depth of an object, as defined by pictorial cues, modulates the precision of visual processing for close objects.
Topics: Cues; Depth Perception; Humans; Judgment; Visual Perception
PubMed: 34585320
DOI: 10.3758/s13423-021-02006-8 -
Journal of Cataract and Refractive... Feb 2020The extended depth-of-focus (EDOF) intraocular lens (IOL) is an emerging technology that is designed to improve range of vision, especially at intermediate distances. In... (Review)
Review
The extended depth-of-focus (EDOF) intraocular lens (IOL) is an emerging technology that is designed to improve range of vision, especially at intermediate distances. In this review, we describe the clinical performance of 4 emerging EDOF IOL technologies; that is, small aperture, bioanalogic, diffractive optics, and nondiffractive optical manipulations. The American Academy of Ophthalmology generated a consensus statement for EDOF IOLs that provided benchmarks and recommendations for classifying an implant as an EDOF IOL as well as standardized testing criteria for evaluating performance. Although many types of EDOF technologies are being developed, there are important differences in their performance that require further testing and evaluation.
Topics: Biomedical Technology; Depth Perception; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Optics and Photonics; Patient Satisfaction; Phacoemulsification; Prosthesis Design; Pseudophakia; Refraction, Ocular; Visual Acuity
PubMed: 32126045
DOI: 10.1097/j.jcrs.0000000000000109 -
Perception Jun 2023The horopter's history may partly be responsible for its ambiguous psychophysical definitions and obscured physiological significance. However, the horopter is a useful...
The horopter's history may partly be responsible for its ambiguous psychophysical definitions and obscured physiological significance. However, the horopter is a useful clinical tool integrating physiological optics and binocular vision. This article aims to help understand how it could come to such different attitudes toward the horopter. After the basic concepts underlying binocular space perception and stereopsis are presented, the horopter's old ideas that influence today's research show their inconsistencies with the conceptualized binocular vision. Two recent geometric theories of the horopter with progressively higher eye model fidelity that resolve the inconsistencies are reviewed. The first theory corrects the 200-year-old Vieth-Müller circle still used as a geometric horopter. The second theory advances Ogle's classical work by modeling empirical horopters as conic sections in the binocular system with the asymmetric eye model that accounts for the observed misalignment of optical components in human eyes. Its extension to iso-disparity conics is discussed.
Topics: Humans; Eye Movements; Eye; Vision, Binocular; Depth Perception; Space Perception; Vision Disparity
PubMed: 37106522
DOI: 10.1177/03010066231170380 -
Current Biology : CB May 2021Depth perception helps animals interact with a three-dimensional world. A new study presents a novel paradigm for studying depth perception in naturally climbing mice...
Depth perception helps animals interact with a three-dimensional world. A new study presents a novel paradigm for studying depth perception in naturally climbing mice and links their behavior to binocular disparity signals in primary visual cortical neurons.
Topics: Animals; Mice; Neurons; Vision Disparity; Vision, Ocular; Visual Cortex
PubMed: 34033773
DOI: 10.1016/j.cub.2021.03.066 -
Journal of Optometry 2021
Topics: Depth Perception; Humans; Vision, Binocular
PubMed: 34176573
DOI: 10.1016/j.optom.2021.06.001