Binocular fusion in Panum’s limiting case of stereopsis obeys the uniqueness constraint

2001 ◽  
Vol 44 (1) ◽  
pp. 40-48 ◽  
Author(s):  
Zhihong Wang ◽  
Xinnian Wu ◽  
Rui Ni ◽  
Yunjiu Wang
Keyword(s):  
Binocular Fusion ◽  
Uniqueness Constraint ◽  
Limiting Case

Modifications of the Classical Notion of Panum's Fusional Area

Perception ◽  
1980 ◽  
Vol 9 (6) ◽  
pp. 671-682 ◽  
Author(s):  
Peter Burt ◽  
Bela Julesz
Keyword(s):  
Visual Field ◽  
Angular Separation ◽  
Critical Value ◽  
Binocular Fusion ◽  
Classical Notion ◽  
Disparity Gradient ◽  
The Absolute ◽  
The Difference ◽  
The Individual ◽  
Limiting Case

It is generally believed that there is an absolute disparity limit for binocular fusion; objects with disparities within this limit, known as Panum's fusional area, will appear fused and single, while objects with disparities outside the limit appear double. It is demonstrated, however, that the disparity gradient, rather than the disparity magnitude, dictates binocular fusion when several objects occur near one another in the visual field. The disparity gradient is defined as the difference between the disparities of neighboring objects divided by their angular separation. If this ratio exceeds a critical value (∼1) then fusion does not occur, even though the absolute disparities of the individual objects may be well within the classical Panum's area. This discovery leads to the reinterpretation of several enigmatic phenomena in stereopsis, including Panum's limiting case.

How We See the World in Depth

2021 ◽  
pp. 370-403
Author(s):  
Stephen Grossberg
Keyword(s):  
Necker Cube ◽  
Critical Role ◽  
Boundary Surface ◽  
Simulated Data ◽  
Natural Scenes ◽  
Binocular Fusion ◽  
3D Vision ◽  
Random Dot Stereograms ◽  
Boundary Grouping ◽  
Limiting Case

This chapter explains how 3D vision and figure-ground perception occur in our brains. It shows how the 2D boundary and surface processes that are described in earlier chapters naturally generalize to 3D via both the FACADE (Form-And-Color-And-DEpth) theory of 3D vision and figure-ground perception, and the 3D LAMINART model that generalizes the laminar cortical circuits of Chapter 10 to 3D and naturally embodies and generalizes FACADE. Contrast-specific binocular fusion and contrast-invariant boundary formation are explained in terms of identified cells in specific layers of cortical areas V1 and V2. The correspondence problem is solved using a disparity filter that eliminates false binocular matches in layer 2/3 of V2, while it chooses the 3D binocular boundary grouping that is best supported by scenic cues. The critical role of monocular boundary information in figure-ground perception is explained and used to simulate DaVinci stereopsis percepts, along with surface-to-boundary surface contour signals and a fixation plane bias due to life-long experiences with fixated scenic features. Simulated data include the Venetian blind effect, Panum’s limiting case, dichoptic masking, 3D Craik-O’Brien-Cornsweet effect, Julesz random dot stereograms, 3D percepts of 2D pictures of shaded ellipses and discrete textures, simultaneous fusion and rivalry percepts when viewing Kulikowski and Kaufman stereograms, stimulus rivalry and eye rivalry, and bistable percepts of slanted surfaces, including the Necker cube. The size-disparity correlation enables signals from multiple scales to cooperate and compete to generate boundary representations at multiple depths. 3D percepts of natural scenes from stereograms are also simulated with these circuits.

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

Suppression of γ’ Precipitation in a Laser-Melted Nickel-Base Alloy

1977 ◽  
Vol 35 ◽  
pp. 270-271
Author(s):  
J. M. Walsh ◽  
J. C. Whittles ◽  
B. H. Kear ◽  
E. M. Breinan
Keyword(s):  
Cooling Rate ◽  
Base Alloy ◽  
Material Surface ◽  
Intimate Contact ◽  
Absorbed Power ◽  
Perfect Contact ◽  
Nickel Base ◽  
Rapidly Solidified ◽  
Limiting Case ◽  
The Heat Transfer Coefficient

Conventionally cast γ’ precipitation hardened nickel-base superalloys possess well-defined dendritic structures and normally exhibit pronounced segregation. Splat quenched, or rapidly solidified alloys, on the other hand, show little or no evidence for phase decomposition and markedly reduced segregation. In what follows, it is shown that comparable results have been obtained in superalloys processed by the LASERGLAZE™ method.In laser glazing, a sharply focused laser beam is traversed across the material surface at a rate that induces surface localized melting, while avoiding significant surface vaporization. Under these conditions, computations of the average cooling rate can be made with confidence, since intimate contact between the melt and the self-substrate ensures that the heat transfer coefficient is reproducibly constant (h=∞ for perfect contact) in contrast to the variable h characteristic of splat quenching. Results of such computations for pure nickel are presented in Fig. 1, which shows that there is a maximum cooling rate for a given absorbed power density, corresponding to the limiting case in which melt depth approaches zero.

Binocular fusion time in sleep-derived subjects.

1969 ◽  
Author(s):  
C. E. Melton ◽  
Marlene Wicks
Keyword(s):  
Binocular Fusion

Cartesian Fingerprints in Beckett's Imagination Dead Imagine

2012 ◽  
Vol 21 (2) ◽  
pp. 223-243
Author(s):  
Irit Degani-Raz
Keyword(s):  
The Self ◽  
Levels Of Abstraction ◽  
The Media ◽  
The Mind ◽  
Limiting Case

The idea that Beckett investigates in his works the limits of the media he uses has been widely discussed. In this article I examine the fiction Imagination Dead Imagine as a limiting case in Beckett's exploration of limits at large and the limits of the media he uses in particular. Imagination Dead Imagine is shown to be the self-reflexive act of an artist who imaginatively explores the limits of that ultimate medium – the artist's imagination itself. My central aim is to show that various types of structural homologies (at several levels of abstraction) can be discerned between this poetic exploration of the limits of imagination and Cartesian thought. The homologies indicated here transcend what might be termed as ‘Cartesian typical topics’ (such as the mind-body dualism, the cogito, rationalism versus empiricism, etc.). The most important homologies that are indicated here are those existing between the role of imagination in Descartes' thought - an issue that until only a few decades ago was quite neglected, even by Cartesian scholars - and Beckett's perception of imagination. I suggest the use of these homologies as a tool for tracing possible sources of inspiration for Beckett's Imagination Dead Imagine.

Mathematical modelling of salt purification by recrystallization. Countercurrent arrangement

1986 ◽  
Vol 51 (11) ◽  
pp. 2481-2488
Author(s):  
Benitto Mayrhofer ◽  
Jana Mayrhoferová ◽  
Lubomír Neužil ◽  
Jaroslav Nývlt
Keyword(s):  
Steady State ◽  
Simple Model ◽  
Mathematical Modelling ◽  
Distribution Coefficient ◽  
Mother Liquor ◽  
Equilibrium Temperature ◽  
Operating Conditions ◽  
Limiting Case

The paper presents a simple model of recrystallization with countercurrent flows of the solution and the crystals being purified. The model assumes steady-state operating conditions, an equilibrium between the outlet streams of each stage, and the same equilibrium temperature and distribution coefficient for all stages. With these assumptions, the model provides the basis for analyzing the variation in the degree of purity as a function of the number of recrystallization stages. The analysis is facilitated by the use of a diagram constructed for the limiting case of perfect removal of the mother liquor from the crystals between the stages.

Five Modes of Scepticism

2019 ◽  
Author(s):  
Stefan Sienkiewicz
Keyword(s):  
Sextus Empiricus ◽  
Theoretical Assumptions ◽  
Limiting Case ◽  
Do So

This book offers an account of the functioning of the five Agrippan modes of scepticism as presented in the works of Sextus Empiricus. These five modes (of disagreement, hypothesis, infinite regression, reciprocity, and relativity) are analysed, individually, in the book’s first five chapters, and, collectively, in its sixth. Two perspectives on these modes are distinguished from one another—a dogmatic perspective which considers how a dogmatic philosopher might come to suspend judgement on the basis of these modes and a sceptical perspective which considers how a sceptic might come to do so. It is argued that the standard way in which these modes have been understood has been from a dogmatic perspective. The book opens up an alternative sceptical perspective on the modes according to which mode of disagreement (or one version of it) is equivalent to the sceptic’s method of equipollence, and the modes of hypothesis, infinite regression, and reciprocity are different instances of that method (with the mode of hypothesis being a limiting case of the method). It is also argued that the mode of relativity is inconsistent with the mode of disagreement and should be discarded when considering how the modes work together in a combined sceptical strategy. The final chapter offers an account of four different ways in which the modes might be combined together and concludes that each of these ways turns on a number of theoretical assumptions which the sceptic is not in a position to make.

scholarly journals On the flow of MHD generalized maxwell fluid via porous rectangular duct

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 989-1002
Author(s):  
Aamir Farooq ◽  
Muhammad Kamran ◽  
Yasir Bashir ◽  
Hijaz Ahmad ◽  
Azeem Shahzad ◽  
...  
Keyword(s):  
Fluid Model ◽  
Maxwell Fluid ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Rectangular Duct ◽  
Modified Darcy’S Law ◽  
Initial Boundary Value ◽  
Generalized Maxwell Fluid ◽  
Limiting Case ◽  
The Impact

Abstract The purpose of this proposed investigation is to study unsteady magneto hydrodynamic (MHD) mixed initial-boundary value problem for incompressible fractional Maxwell fluid model via oscillatory porous rectangular duct. Considering the modified Darcy’s law, the problem is simplified by using the method of the double finite Fourier sine and Laplace transforms. As a limiting case of the general solutions, the same results can be obtained for the classical Maxwell fluid. Also, the impact of magnetic parameter, porosity of medium, and the impact of various material parameters on the velocity profile and the corresponding tangential tensions are illuminated graphically. At the end, we will give the conclusion of the whole paper.

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