Types of Size Disparity and the Perception of Surface Slant

Perception ◽  
1997 ◽  
Vol 26 (12) ◽  
pp. 1503-1517 ◽  
Author(s):  
Byron J Pierce ◽  
Ian P Howard
Keyword(s):  
Vertical Axis ◽  
Textured Surface ◽  
Curved Boundary ◽  
Surface Slant ◽  
Size Disparity ◽  
Horizontal Size ◽  
Depth Contrast ◽  
Depth Enhancement ◽  
Vertical Size

We examined (i) perceived slant of a textured surface about a vertical axis as a function of disparity magnitude for horizontal-size disparity, vertical-size disparity, and overall-size disparity; and (ii) interactions between patterns with various types and magnitudes of size disparity and superimposed or adjacent zero-disparity stimuli. Horizontal-size disparity produced slant which increased with increasing disparity, was enhanced by superimposed zero-disparity stimuli, and induced contrasting slant in superimposed or adjacent zero-disparity stimuli. Vertical-size disparity produced opposite slant (induced effect) which was reduced to near zero by a superimposed zero-disparity pattern and both patterns appeared as one surface. Adjacent vertical-size-disparity and zero-disparity patterns appeared as separate surfaces with a wide curved boundary. Overall-size disparity produced slant which was enhanced by a superimposed zero-disparity pattern and less so by a zero-disparity line, and induced more slant in a zero-disparity line than in a zero-disparity pattern. The results are discussed in terms of depth underestimation of isolated surfaces, depth enhancement, depth contrast, and the processing of deformation disparity.

Types of Shear Disparity and the Perception of Surface Inclination

Perception ◽  
1998 ◽  
Vol 27 (2) ◽  
pp. 129-145 ◽  
Author(s):  
Ian P Howard ◽  
Byron J Pierce
Keyword(s):  
Opposite Direction ◽  
Horizontal Axis ◽  
Vertical Shear ◽  
Wide Area ◽  
Textured Surface ◽  
Horizontal Shear ◽  
Curved Boundary ◽  
Surface Inclination ◽  
Depth Contrast ◽  
Depth Enhancement

A study is reported of (i) the perceived inclination of a textured surface in depth about a horizontal axis as a function of disparity magnitude for horizontal-shear disparity, vertical-shear disparity, and rotation disparity; and (ii) interactions between patterns with shear or rotation disparity and superimposed or adjacent patterns or lines with zero disparity. Horizontal-shear disparity produced strong inclination which was enhanced by superimposed or adjacent zero-disparity stimuli. It produced little or no inclination contrast in superimposed or adjacent zero-disparity stimuli. Vertical-shear disparity produced inclination in the opposite direction (induced effect) which was reduced to near zero by a superimposed zero-disparity pattern. Adjacent vertical-shear and zero-disparity patterns appeared inclined at slightly different angles with a wide curved boundary. This suggests that vertical-shear disparities are averaged over a wide area. Rotation disparity produced minimal inclination. A superimposed or adjacent zero-disparity line appeared strongly inclined. A superimposed or adjacent zero-disparity pattern appeared vertical and caused the pattern with rotation disparity to appear inclined. Four mechanisms are proposed to account for the results: depth contrast, depth enhancement, deformation-disparity processing, and disparity transfer arising from cyclovergence.

Depth Interactions between Inclined and Slanted Surfaces in Vertical and Horizontal Orientations

Perception ◽  
1998 ◽  
Vol 27 (1) ◽  
pp. 87-103 ◽  
Author(s):  
Byron J Pierce ◽  
Ian P Howard ◽  
Catina Feresin
Keyword(s):  
Vertical Shear ◽  
Test Surface ◽  
Horizontal Shear ◽  
Frontal Surface ◽  
Horizontal Orientation ◽  
Size Disparity ◽  
Horizontal Size ◽  
Depth Contrast ◽  
Effects Of Rotation ◽  
Vertical Size

Depth interactions between a frontal test surface and an adjacent induction surface were measured as a function of the type of disparity in the induction surface and of the vertical/horizontal orientation of the boundary between the surfaces. The types of disparity were 4° horizontal-shear disparity, 4° vertical-shear disparity, and 4° rotation disparity; 4% horizontal-size disparity, 4% vertical-size disparity, and 4% overall-size disparity. Depth contrast in a frontal surface was produced by surfaces containing horizontal-size disparity but not by those containing horizontal-shear disparity. Vertical-shear and vertical-size disparities produced induced effects in both the induction and the test surface, which is here explained in terms of deformation-disparity processing. Effects of rotation disparity on the test surface can be accounted for in terms of cyclovergence, deformation disparity, and perhaps also depth contrast. The fact that horizontal-size disparity produced more depth contrast than horizontal-shear disparity is due to an anisotropy of disparity processing rather than the relative orientation of the surfaces. Ground surfaces appeared more slanted than ceiling surfaces. Surfaces containing horizontal disparities produced a sharp boundary with the test surface because horizontal disparities are processed locally. Surfaces with vertical disparities produced a gradual boundary with the test surface because vertical disparities are processed over a wider area.

Conflicts with Extraretinal and Monocular Cues Cause the Small Range of the Induced Effect

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 79-79
Author(s):  
M S Banks ◽  
B T Backus
Keyword(s):  
Retinal Images ◽  
Eye Position ◽  
Small Range ◽  
Geometric Effect ◽  
Apparent Rotation ◽  
Surface Slant ◽  
Horizontal Size ◽  
Vertical Size

A vertical magnifier before one eye causes the induced effect: an apparent rotation of frontal surfaces toward that eye. The rotation required to restore apparent frontoparallelism grows linearly up to ∼4% magnification, but plateaus at 8%. We examined the cause of the plateau. Horizontal disparities (quantified by horizontal size ratios, HSRs) are ambiguous indicators of surface slant. Various retinal and nonretinal signals can allow veridical slant estimation from HSR, sensed eye position, vertical disparities (vertical size ratios, VSRs), and monocular cues. Vertical or horizontal magnification of one eye's image alters the natural relationships among HSR, VSR, eye position, and monocular cues. We argue that the induced-effect plateau is caused by conflicts between these means of estimating slant. A plateau is not observed in the geometric effect because some of the conflicts do not occur with horizontal magnification. Two experiments were designed to test this hypothesis. When strong monocular cues were present, plateaux occurred at ∼8% magnification in the induced, but not the geometric effect. When monocular slant cues were made useless, induced-effect plateaux were abolished. Even with strong monocular cues present, plateaux in the induced effect were eliminated when eye position was consistent with the vertical magnification in the retinal images. The smaller range of the induced effect can only be understood from consideration of all the signals involved in slant estimation.

scholarly journals Spatial limitation of vertical-size disparity processing

1997 ◽  
Vol 37 (20) ◽  
pp. 2871-2878 ◽  
Author(s):  
Hirohiko Kaneko ◽  
Ian Howard
Keyword(s):  
Size Disparity ◽  
Vertical Size ◽  
Spatial Limitation

scholarly journals Сomputed tomography anatomy of the orbital apex

2015 ◽  
Vol 8 (2) ◽  
pp. 28-34
Author(s):  
Oleg Yur’yevich Yatsenko
Keyword(s):  
Differential Diagnosis ◽  
Optic Nerve ◽  
Soft Tissues ◽  
Standard Technique ◽  
Section Thickness ◽  
Orbital Apex ◽  
Horizontal Size ◽  
External Part ◽  
Volume Characteristics ◽  
Vertical Size

The apex of the bony orbit and its soft tissues are most difficult to investigate. Meanwhile just pathological processes in this area cause several serious conditions which could lead to blindness and in many cases to disability. Purpose: to study linear and volume indices of the bony orbital apex and its soft content in normal conditions. Material and methods: 210 patients (266 orbits) are examined. Both orbits were investigated in 56 patients (112 orbits) with no orbital pathology. In patients with unilateral orbital involvement, the normal orbit was investigated (154 orbits). Among examined patients, 86 were men and 124 women. Mean age was 41.2 ± 10.4 years. The CT scan according to the standard technique obtaining axial and frontal sections was carried out in all patients (section thickness was 1.0 mm; interval - 1.0 mm). Results and discussions: The average horizontal size of the external part of an orbit in men was 22.2 ± 0.41 mm (range 17-28 mm). The same size in women was 21.4 ± 0.23 mm (17-26 mm). The vertical size of the external part of the orbit in men is equal to 23.12 ± 0.38 mm, in average and at women - 23.4 ± 0.31 mm. Orbital apex length is 16-24 mm (average 20.1 ± 0.47 mm) in men, in women it is 15-23 mm (average 19,2 ± 0,35 mm). In the article, normal volume of the orbital apex, of the optic nerve, extraocular muscles and orbital fat are presented. Ratios of volume characteristics of studied structures of the orbital apex are displayed. Conclusions: Volume characteristics of the orbital apex and its soft content could be useful to understand the pathogenesis of pathological processes in this area. They could be also used to carry out the differential diagnosis between true and false proptosis, and for surgery planning.

Asymptotic model of the mobile interface between two liquids in a thin porous stratum

2002 ◽  
Vol 473 ◽  
pp. 59-81 ◽  
Author(s):  
M. PANFILOV ◽  
M. BUÈS
Keyword(s):  
Asymptotic Model ◽  
Immiscible Liquids ◽  
Fluid Medium ◽  
Flow Rates ◽  
Mobile Interface ◽  
Equilibrium Processes ◽  
Apparent Diffusion ◽  
Horizontal Size ◽  
Rayleigh Taylor Instability ◽  
Vertical Size

We propose a new generalized model to describe deformations of the mobile interface separating two immiscible liquids in a porous medium. The densities and the viscosities of the fluids can have any value. The horizontal size of the interface is much greater than the vertical size of the domain. Unlike the classical theory, the new model describes gravitational non-equilibrium processes, including the Rayleigh–Taylor instability which appears in the form of a negative apparent diffusion parameter. Several flow regimes are established depending on the ratio between gravity and the elastic fluid/medium forces, and between the vertical and horizontal flow rates. The model is used to analyse the evolution of the interface during the free spreading of one liquid over another. This is characterized by the presence of interface degeneration points. The explicit solution to the problem of oil and water flow towards a well is presented as an application to oil reservoirs.

Spatial Interactions Modulate Stereoscopic Processing of Horizontal and Vertical Disparities

Perception ◽  
1997 ◽  
Vol 26 (6) ◽  
pp. 693-706
Author(s):  
Mark W Pettet
Keyword(s):  
Size Effect ◽  
Weighted Average ◽  
Vertical Axis ◽  
Spatial Interactions ◽  
Depth Contrast ◽  
Direction Opposite ◽  
Lines Of Evidence

Stereoscopic processing of horizontal and vertical disparities was assessed by measuring how the stereoscopic appearance of test dots near the fixation point was influenced by inducing stimuli in the near periphery. The inducing stimuli were differentially magnified in the two eyes and varied in horizontal eccentricity. As expected, when the inducers were horizontally magnified, the test dots exhibited depth contrast, slanting in depth in a direction opposite the slant of the inducing dots. When the inducers were vertically magnified, the test dots slanted in depth around a vertical axis toward the eye with the larger vertical image (the induced-size effect). However, two lines of evidence suggested that an eccentricity-dependent weighted average of horizontal and vertical components of inducer-dot magnification determined the slant of the test dots. First, as the horizontal eccentricity of the inducing dots was varied, the trend of test-dot slants measured with vertical inducer magnifications was predicted by the trend of test-dot slants measured with horizontal inducer magnifications. Second, test-dot slants measured with a combination of both horizontal and vertical inducer magnification could be predicted by simply adding test-dot slants measured with either horizontal or vertical inducer magnification alone.

scholarly journals Vertical size disparity pooling across attended color and contrast

2015 ◽  
Vol 15 (12) ◽  
pp. 833
Author(s):  
Benjamin Backus ◽  
Baptiste Caziot
Keyword(s):  
Size Disparity ◽  
Vertical Size

Method of Analyzing the Size of Voids Beneath Rigid Pavement Slabs

2011 ◽  
Vol 418-420 ◽  
pp. 1516-1519
Author(s):  
Yan Hui Zhong ◽  
Bei Zhang ◽  
Ming Ming Ren ◽  
Cheng Chao Guo ◽  
Chu Chu Xia
Keyword(s):  
Bearing Capacity ◽  
Wave Amplitude ◽  
Rigid Pavement ◽  
Advanced Method ◽  
Horizontal Size ◽  
Vertical Size

The size of voids beneath rigid pavement slabs is an important factor which influences the bearing capacity of roads. GPR is an advanced method for detecting voids beneath rigid pavement slabs. Combined with drilling and sampling, equations including parameters of GPR wave amplitude, horizontal size and vertical size of voids are established for analyzing the size of voids. Then, based on the equations, the horizontal size and vertical size of voids can be calculated according to the actual GPR wave amplitude.

Cue Conflict and Stereoscopic Surface Slant about Horizontal and Vertical Axes

Perception ◽  
1994 ◽  
Vol 23 (6) ◽  
pp. 645-658 ◽  
Author(s):  
Colin Ryan ◽  
Barbara Gillam
Keyword(s):  
Vertical Axis ◽  
Vertical Line ◽  
Planar Surface ◽  
Surface Configuration ◽  
Surface Slant ◽  
Cue Conflict ◽  
The Way

The way in which a planar surface is defined or configured may affect its apparent slant about a given axis, and the magnitude of slant-axis anisotropies. The authors have previously suggested that (i) these within-axis and between-axis configuration effects may be attributable, in part at least, to the perspective—disparity conflict generated when geometrically frontoparallel configured surfaces are slanted stereoscopically; and (ii) that implicit contours, defined by line endings or conjunctions, may have effects analogous to those seen with explicit contours. These possibilities were directly examined in two experiments. In experiment 1, slant-axis anisotropy was progressively induced by adding horizontal lines to a vertical-line (zero anisotropy) grid under conditions of cue conflict; slants about the vertical (but not the horizontal) were attenuated—demonstrating a clear and systematic nexus between surface configuration and slant-axis anisotropy. The presence of regular implicit horizontals similarly and selectively attenuated the slant perceived about the vertical. In experiment 2, cue conflict was seen to exacerbate slant-axis anisotropy, but clearly could not fully account for it. There was an axis asymmetry in the effect of degrading implicit contours: degradation had a marked impact on perceived slant about the horizontal but not the vertical axis.

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