Disparity Limit for Binocular Fusion in Fovea

Qin, Damin; Takamatsu, Mamoru; Nakashima, Yoshio

doi:10.1007/s10043-006-0034-5

Cited by 15 publications

(20 citation statements)

References 10 publications

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“…However, not all of these stereo matches will be fusible. In particular, there are limits on disparity gradients for stereopsis (Burt & Julesz, 1980;Tyler, 1975) and limits on the vertical offsets between matched features (Qin, Takamatsu, & Nakashima, 2006;Van Ee & Schor, 2000). In order to visualize those disparities that fall within these limits, in Figure 6 we show the subset of matches that are likely to be fusible by the human visual system.…”

Section: Virtual Illumination Mappingmentioning

confidence: 97%

“…This created a correlation map centered on the epipolar line (Figure 7a). By default we searched for correspondence by applying a tolerance of 612 arcmin (648 pixels) around the epipolar line based on experimental results on human fusibility limits for vertical offsets between the two eyes (Qin et al, 2006;Van Ee & Schor, 2000). We selected corresponding points as the peak of the correlation landscape in the right image for point P L , which typically gave rise to a close match between the subimages from the left and right images (Figure 7b).…”

Section: Correspondence Is Not Limited To Epipolar Linesmentioning

confidence: 99%

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Key characteristics of specular stereo

2014

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Because specular reflection is view-dependent, shiny surfaces behave radically differently from matte, textured surfaces when viewed with two eyes. As a result, specular reflections pose substantial problems for binocular stereopsis. Here we use a combination of computer graphics and geometrical analysis to characterize the key respects in which specular stereo differs from standard stereo, to identify how and why the human visual system fails to reconstruct depths correctly from specular reflections. We describe rendering of stereoscopic images of specular surfaces in which the disparity information can be varied parametrically and independently of monocular appearance. Using the generated surfaces and images, we explain how stereo correspondence can be established with known and unknown surface geometry. We show that even with known geometry, stereo matching for specular surfaces is nontrivial because points in one eye may have zero, one, or multiple matches in the other eye. Matching features typically yield skew (nonintersecting) rays, leading to substantial ortho-epipolar components to the disparities, which makes deriving depth values from matches nontrivial. We suggest that the human visual system may base its depth estimates solely on the epipolar components of disparities while treating the ortho-epipolar components as a measure of the underlying reliability of the disparity signals. Reconstructing virtual surfaces according to these principles reveals that they are piece-wise smooth with very large discontinuities close to inflection points on the physical surface. Together, these distinctive characteristics lead to cues that the visual system could use to diagnose specular reflections from binocular information.

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Section: Virtual Illumination Mappingmentioning

confidence: 97%

Section: Correspondence Is Not Limited To Epipolar Linesmentioning

confidence: 99%

Key characteristics of specular stereo

2014

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“…Disparities up to 30 arcmin were included to provide sufficient operational space to the staircase, in particular at the lowest adaptation luminance level. Such horizontal disparity is still within the fusion range [Qin et al 2006]. No convergence to disparity thresholds higher than 15 arcmin was observed in practice.…”

Section: Disparity Detection Threshold (Exp 3)mentioning

confidence: 80%

Stereo Day-for-Night

Kellnhofer

Ritschel

Vangorp

et al. 2014

ACM Trans. Appl. Percept.

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Several approaches attempt to reproduce the appearance of a scotopic low-light night scene on a photopic display ("day-fornight") by introducing color desaturation, loss of acuity and the Purkinje shift towards blue colors. We argue that faithful stereo reproduction of night scenes on photopic stereo displays requires manipulation of not only color but also binocular disparity. To this end, we performed a psychophysics experiment to devise a model of disparity at scotopic luminance levels. Using this model, we can match binocular disparity of a scotopic stereo content displayed on a photopic monitor to the disparity that would be perceived if the scene was actually scotopic. The model allows for real-time computation of common stereo content as found in interactive applications such as simulators or computer games.

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“…One possibility is that the unusual properties of specular disparities outlined above act as an intrinsic marker that the underlying binocular information should therefore be rejected when estimating 3D shape. To test this idea, we applied a "disparity detectability constraint (DDC)," using performance limits of the human visual system on outliers, horizontal disparity gradients, and the magnitude of vertical disparities (19)(20)(21) to identify and remove unreliable portions of the virtual surface. We then considered participants' estimated depth judgments by separating settings from the "specular" condition into two classes: (i) those that come from reliable portions of the virtual surface, and (ii) those that come from portions that are identified as unreliable by the DDC criteria.…”

Section: Resultsmentioning

confidence: 99%

“…To define the DDC, we used thresholds for vertical disparities of 12 arcmin (20,21) and thresholds of horizontal disparity gradients of one (19). A disparity was identified as unreliable on the basis of passing either threshold.…”

Section: Methodsmentioning

confidence: 99%

Specular reflections and the estimation of shape from binocular disparity

Muryy

Welchman

Blake

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Binocular stereopsis is a powerful visual depth cue. To exploit it, the brain matches features from the two eyes' views and measures their interocular disparity. This works well for matte surfaces because disparities indicate true surface locations. However, specular (glossy) surfaces are problematic because highlights and reflections are displaced from the true surface in depth, leading to information that conflicts with other cues to 3D shape. Here, we address the question of how the visual system identifies the disparity information created by specular reflections. One possibility is that the brain uses monocular cues to identify that a surface is specular and modifies its interpretation of the disparities accordingly. However, by characterizing the behavior of specular disparities we show that the disparity signals themselves provide key information ("intrinsic markers") that enable potentially misleading disparities to be identified and rejected. We presented participants with binocular views of specular objects and asked them to report perceived depths by adjusting probe dots. For simple surfaces-which do not exhibit intrinsic indicators that the disparities are "wrong"-participants incorrectly treat disparities at face value, leading to erroneous judgments. When surfaces are more complex we find the visual system also errs where the signals are reliable, but rejects and interpolates across areas with large vertical disparities and horizontal disparity gradients. This suggests a general mechanism in which the visual system assesses the origin and utility of sensory signals based on intrinsic markers of their reliability.psychophysics | perception | gloss | texture | computational analysis S hiny objects such as sports cars, jewelry, and consumer electronics can be beautiful to look at. However, such objects pose a difficult challenge to the visual system: if all (or most) of the light reaching the eye comes from the reflections of other nearby objects, how does the viewer discern the object itself? This problem becomes more acute when viewing with two eyes. Unlike shading or texture markings, the positions of reflections relative to a specular (shiny) surface depend on the observer's viewpoint. This means that when the surface is viewed binocularly (i.e., from two viewpoints at the same time), corresponding reflections fall on different surface locations. In consequence, the binocular disparities created by specular reflections indicate depth positions displaced from the object's physical surface (1, 2) and the 3D shape specified by disparity can be radically different from the true shape of the object. For special cases, such as an ideal planar mirror, the visual system could not, even in principle, estimate the true depths of the surface from the reflections. However, for more complex shapes, such as a polished metal kettle, we rarely encounter problems judging shape. Most models of biological vision place heavy weight on binocular disparity cues, whereas artificial systems often rely almost exclusively ...

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Disparity Limit for Binocular Fusion in Fovea

Cited by 15 publications

References 10 publications

Key characteristics of specular stereo

Key characteristics of specular stereo

Stereo Day-for-Night

Specular reflections and the estimation of shape from binocular disparity

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