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.

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.

scholarly journals Stereopsis is adaptive for the natural environment

2015 ◽  
Vol 1 (4) ◽  
pp. e1400254 ◽  
Author(s):  
William W. Sprague ◽  
Emily A. Cooper ◽  
Ivana Tošić ◽  
Martin S. Banks
Keyword(s):  
Visual System ◽  
Natural Environment ◽  
Cortical Neurons ◽  
Three Dimensional ◽  
Retinal Images ◽  
Eye Position ◽  
Small Range ◽  
Natural Distribution ◽  
Natural Tasks ◽  
Correspondence Search

Humans and many animals have forward-facing eyes providing different views of the environment. Precise depth estimates can be derived from the resulting binocular disparities, but determining which parts of the two retinal images correspond to one another is computationally challenging. To aid the computation, the visual system focuses the search on a small range of disparities. We asked whether the disparities encountered in the natural environment match that range. We did this by simultaneously measuring binocular eye position and three-dimensional scene geometry during natural tasks. The natural distribution of disparities is indeed matched to the smaller range of correspondence search. Furthermore, the distribution explains the perception of some ambiguous stereograms. Finally, disparity preferences of macaque cortical neurons are consistent with the natural distribution.

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.

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.

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.

scholarly journals The increase of signal-to-noise ratio in the spatial separation of signals by the curvature of the wavefront

2018 ◽  
Vol 226 ◽  
pp. 05010 ◽  
Author(s):  
Aleksandr Okorochkov ◽  
Bogdan Malyutin ◽  
Gleb Khripkov
Keyword(s):  
Focal Spot ◽  
Signal To Noise Ratio ◽  
Spatial Separation ◽  
Signal To Noise ◽  
Focal Distance ◽  
Phased Antenna Array ◽  
Horizontal Size ◽  
Noise Ratio ◽  
Research Show ◽  
Vertical Size

The article presents the results of the research of the dependence of the signal-to-noise ratio in the focal spot of the reflecting passive phased antenna array (PPAA), made of planar diffraction elements, on the orientation of the PPAA relative to the structure of the interference field, its dimensions and distance from PPAA plane to the focal spot. The results of the research show that the signal-to-noise ratio mainly depends on the horizontal size of the PPAA. The increase of the vertical size of the array leads to the fact that the focal distance corresponding to the maximum of the signal-to-noise ratio increases with the practically unchanged value of this maximum.

New form of Transmission Cross Coefficient for High-Resolution Imaging

1990 ◽  
Vol 48 (1) ◽  
pp. 60-61
Author(s):  
Kazuo Ishizuka
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Function ◽  
Incident Beam ◽  
Optical Microscope ◽  
Strong Interactions ◽  
Small Range ◽  
Specimen Thickness ◽  
Beam Direction ◽  
Diffracted Waves

It is well known that taking into account spacial and temporal coherency of illumination as well as the wave aberration is important to interpret an image of a high-resolution electron microscope (HREM). This occues, because coherency of incident electrons restricts transmission of image information. Due to its large spherical and chromatic aberrations, the electron microscope requires higher coherency than the optical microscope. On an application of HREM for a strong scattering object, we have to estimate the contribution of the interference between the diffracted waves on an image formation. The contribution of each pair of diffracted waves may be properly represented by the transmission cross coefficients (TCC) between these waves. In this report, we will show an improved form of the TCC including second order derivatives, and compare it with the first order TCC.In the electron microscope the specimen is illuminated by quasi monochromatic electrons having a small range of illumination directions. Thus, the image intensity for each energy and each incident direction should be summed to give an intensity to be observed. However, this is a time consuming process, if the ranges of incident energy and/or illumination direction are large. To avoid this difficulty, we can use the TCC by assuming that a transmission function of the specimen does not depend on the incident beam direction. This is not always true, because dynamical scattering is important owing to strong interactions of electrons with the specimen. However, in the case of HREM, both the specimen thickness and the illumination angle should be small. Therefore we may neglect the dependency of the transmission function on the incident beam direction.

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