Spatial and Temporal Properties of Stereoscopic Surface Interpolation

Perception ◽  
10.1068/p5437 ◽  
2005 ◽  
Vol 34 (11) ◽  
pp. 1325-1338 ◽  
Author(s):  
Laurie M Wilcox ◽  
Philip A Duke
Keyword(s):  
Exposure Duration ◽  
Critical Value ◽  
Stereoscopic Vision ◽  
Interpolation Process ◽  
Temporal Constraints ◽  
Shape Discrimination ◽  
Surface Interpolation ◽  
Temporal Properties ◽  
Texture Density ◽  
Wide Range

It is well established that under a wide range of conditions when a sparse collection of texture elements varies smoothly in depth, the spaces between the elements are assigned depth values. This disparity interpolation process has been studied in an effort to define some of its fundamental spatial and temporal constraints. To assess disparity interpolation we employed two tasks: a novel task that relies on the bisection of illusory boundaries created when subjective stereoscopic surfaces intersect, and one that relies on a 3-D shape discrimination. The results of both experiments show that there is no improvement in performance when texture density is increased from near 0.20 to 0.85 or when exposure duration is increased from 50–100 to 1000 ms. This lack of dependence on the addition of features that define the interpolated surface, along with the abrupt decline in performance below a critical value, is consistent with the view that surface interpolation is an important function of human stereoscopic vision.

Visual hyperacuity: spatiotemporal interpolation in human vision

1981 ◽  
Vol 213 (1193) ◽  
pp. 451-477 ◽  
Keyword(s):  
Constant Velocity ◽  
Receptive Fields ◽  
Spatial Separation ◽  
Human Vision ◽  
Interpolation Process ◽  
Vernier Acuity ◽  
Optimal Velocity ◽  
Temporal Properties ◽  
Wide Range ◽  
Temporal Offset

Stroboscopic presentation of a moving object can be interpolated by our visual system into the perception of continuous motion. The precision of this interpolation process has been explored by measuring the vernier discrimination threshold for targets displayed stroboscopically at a sequence of stations. The vernier targets, moving at constant velocity, were presented either with a spatial offset or with a temporal offset or with both. The main results are: (1) vernier acuity for spatial offset is rather invariant over a wide range of velocities and separations between the stations (see Westheimer & McKee 1975); (2) vernier acuity for temporal offset depends on spatial separation and velocity. At each separation there is an optimal velocity such that the strobe interval is roughly constant at about 30 ms; optimal acuity decreases with increasing separation; (3) blur of the vernier pattern decreases acuity for spatial offsets, but improves acuity for temporal offsets (at high velocities and large separations); (4) a temporal offset exactly compensates the equivalent (at the given velocity) spatial offset only for a small separation and optimal velocity; otherwise the spatial offset dominates. A theoretical analysis of the interpolation problem suggests a computational scheme based on the assumption of constant velocity motion. This assumption reflects a constraint satisfied in normal vision over the short times and small distances normally relevant for the interpolation process. A reasonable implementation of this scheme only requires a set of independent, direction selective spatiotemporal channels, that is receptive fields with the different sizes and temporal properties revealed by psychophysical experiments. It is concluded that sophisticated mechanisms are not required to account for the main properties of vernier acuity with moving targets. It is furthermore suggested that the spatiotemporal channels of human vision may be the interpolation filters themselves. Possible neurophysiological implications are briefly discussed.

scholarly journals Drops bouncing off macro-textured superhydrophobic surfaces

2017 ◽  
Vol 824 ◽  
pp. 866-885 ◽  
Author(s):  
Ali Mazloomi Moqaddam ◽  
Shyam S. Chikatamarla ◽  
Iliya V. Karlin
Keyword(s):  
Contact Time ◽  
Numerical Study ◽  
Three Dimensional ◽  
Superhydrophobic Surfaces ◽  
Nonlinear Behaviour ◽  
Textured Surfaces ◽  
Texture Density ◽  
Wide Range ◽  
Quantitative Manner ◽  
The Impact

Recent experiments with droplets impacting macro-textured superhydrophobic surfaces revealed new regimes of bouncing with a remarkable reduction of the contact time. Here we present a comprehensive numerical study that reveals the physics behind these new bouncing regimes and quantifies the roles played by various external and internal forces. For the first time, accurate three-dimensional simulations involving realistic macro-textured surfaces are performed. After demonstrating that simulations reproduce experiments in a quantitative manner, the study is focused on analysing the flow situations beyond current experiments. We show that the experimentally observed reduction of contact time extends to higher Weber numbers, and analyse the role played by the texture density. Moreover, we report a nonlinear behaviour of the contact time with the increase of the Weber number for imperfectly coated textures, and study the impact on tilted surfaces in a wide range of Weber numbers. Finally, we present novel energy analysis techniques that elaborate and quantify the interplay between the kinetic and surface energy, and the role played by the dissipation for various Weber numbers.

Early Motion Processes and the Kinetic Depth Effect

1989 ◽  
Vol 41 (1) ◽  
pp. 183-198 ◽  
Author(s):  
George Mather
Keyword(s):  
Depth Perception ◽  
Short Range ◽  
Three Dimensional ◽  
Visual Display ◽  
Depth Effect ◽  
Temporal Properties ◽  
Early Motion ◽  
Wide Range ◽  
Dimensional Object ◽  
Inter Frame

It has been known for over 30 years that motion information alone is sufficient to yield a vivid impression of three-dimensional object structure. For example, a computer simulation of a transparent sphere, the surface of which is randomly speckled with dots, gives no impression of depth when presented as a stationary pattern on a visual display. As soon as the sphere is made to rotate in a series of discrete steps or frames, its 3-D structure becomes apparent. Three experiments are described which use this stimulus, and find that depth perception in these conditions depends crucially on the spatial and temporal properties of the display: 1. Depth is seen reliably only for between-frame rotations of less than 15°, using two-frame and four-frame sequences. 2. Parametric observations using a wide range of frame durations and inter-frame intervals reveal that depth is seen only for inter-frame intervals below 80 msec and is optimal when the stimulus can be sampled at intervals of about 40–60 msec. 3. Monoptic presentation of two frames of the stimulus is sufficient to yield depth, but the impression is destroyed by dichoptic presentation. These data are in close agreement with the observed limits of direction perception in experiments using “short-range” stimuli. It is concluded that depth perception in the motion display used in these experiments depends on the outputs of low-level or “short-range” motion detectors.

Wide‐Range Pulse‐Shape Discrimination System

1968 ◽  
Vol 39 (2) ◽  
pp. 165-168 ◽  
Author(s):  
C. E. Hollandsworth ◽  
W. P. Bucher
Keyword(s):  
Pulse Shape ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Wide Range

Fluctuating forces on a rigid circular cylinder in confined flow

1976 ◽  
Vol 78 (3) ◽  
pp. 561-576 ◽  
Author(s):  
A. Richter ◽  
E. Naudascher
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Reynolds Numbers ◽  
Critical Value ◽  
Experimental Information ◽  
Rectangular Duct ◽  
Wide Range ◽  
Confined Flow ◽  
The Mean ◽  
Lift And Drag

The fluctuating lift and drag acting on a long, rigidly supported circular cylinder placed symmetrically in a narrow rectangular duct were investigated for various blockage percentages over a wide range of Reynolds numbers around the critical value. The data obtained permit a full assessment of the effect of confinement on the mean-drag coefficient, the root-mean-square values of both the drag and the lift fluctuations, the Strouhal number of the dominant vortex shedding, and the Reynolds number marking transition from laminar to turbulent flow separation. Besides experimental information on a subject on which little is known so far, the paper provides a basis for the deduction of better correction procedures concerning the effects of blockage.

On the Onset of Dynamic Recrystallization in Steels

2011 ◽  
Vol 409 ◽  
pp. 431-436 ◽  
Author(s):  
Gonzalo Varela-Castro ◽  
Jose María Cabrera ◽  
J.M. Prado
Keyword(s):  
Dynamic Recrystallization ◽  
Critical Strain ◽  
Flow Behavior ◽  
Constitutive Models ◽  
Constant Strain Rate ◽  
Critical Value ◽  
Hot Forming ◽  
Wide Range ◽  
Precise Time ◽  
State Of Art

The knowledge of the flow behavior of metallic alloys subjected to hot forming operations is of particular interest for designers and engineers in the practice of industrial forming processes simulations (i.e. rolling mill). Nowadays dynamic recrystallization (DRX) is recognized as one of the most relevant and meaningful mechanisms available for the control of microstructure. This mechanism occurs during hot forming operations over a wide range of metals and alloys and it is known to be as a powerful tool which can be used to the control of the microstructure and properties of alloys. Therefore is important to know, particularly in low stacking fault energy (SFE) materials, the precise time for which DRX is available to act. At constant strain rate such time is defined by a critical strain, εc. Unfortunately this critical value is not directly measurable on the flow curve; as a result different methods have been developed to derive it. Focused on steels, in the present work the state of art on the critical strain for the initiation of DRX is summarized and a review of the different methods and expressions for determining εc is included. The collected data is suitable to feeding constitutive models.

scholarly journals On the semantics of the Japanese infinitive/gerund-clause constructions: Polysemy and temporal constraints

2012 ◽  
Author(s):  
David Y. Oshima
Keyword(s):  
Temporal Sequence ◽  
Semantic Relations ◽  
Temporal Constraints ◽  
The Core ◽  
Pragmatic Enrichment ◽  
Wide Range ◽  
Distinct Sense ◽  
Core Meaning ◽  
State Interpretation

The Japanese infinitive-clause construction (InfCx) and gerund-clause construction (GerCx), which are the most basic subordination structures (considered as coordination structures by some) in the language, may convey a wide range of interclausal semantic relations, including ‘temporal sequence’, ‘cause’, and ‘manner’, largely due to pragmatic enrichment. This work addresses the question of what the core meaning(s) of the two constructions is (are), and demonstrates (i) that the InfCx and GerCx indicate either that the first-clause eventuality precedes or temporally subsumes the second-clause eventuality or that the two clauses stand in the rhetorical relation of contrast, and (ii) that the GerCx has a distinct sense that the InfCx lacks, which gives rise to the ‘resulting state’ interpretation.

Cold Rolling of Foil

1992 ◽  
Vol 206 (2) ◽  
pp. 119-131 ◽  
Author(s):  
N A Fleck ◽  
K L Johnson ◽  
M E Mear ◽  
L C Zhang
Keyword(s):  
Cold Rolling ◽  
Constant Coefficient ◽  
Coulomb Friction ◽  
Master Curve ◽  
Critical Value ◽  
Neutral Zone ◽  
Entry And Exit ◽  
Wide Range ◽  
Dimensional Parameters ◽  
Single Master Curve

A theory of cold rolling of thin gauge strip is presented which, within the idealizations of homogeneous deformation and a constant coefficient of Coulomb friction, rigorously models the elastic deformation of the rolls and the frictional traction at the interface. In contrast with classical theories (3) it is shown that, for gauges less than a critical value, plastic reduction takes place in two zones, at entry and exit, which are separated by a neutral zone in which the rolls are compressed fiat and there is no slip between the rolls and the strip. Roll load and torque are governed by five independent non-dimensional parameters which express the influence of gauge, reduction, friction and front and back tensions. Values of load and torque have been computed (for zero front and back tensions) for a wide range of thickness, reduction and friction and have been found to collapse approximately on to a single master curve.

Novel approach for simulating the elastic properties of porous rocks including the critical porosity phenomena

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. L37-L44 ◽  
Author(s):  
Mikhail Markov ◽  
Elena Kazatchenko ◽  
Aleksandr Mousatov ◽  
Evgeny Pervago
Keyword(s):  
Elastic Properties ◽  
Elastic Moduli ◽  
Phase 1 ◽  
Elastic Solid ◽  
Critical Value ◽  
Porous Rocks ◽  
Rock Falls ◽  
Critical Porosity ◽  
Type Phase ◽  
Wide Range

We tested an approach for calculating the effective elastic properties of rocks taking into account their critical porosity (the percolation threshold). The concept of critical porosity considers that when the porosity of a rock exceeds the critical value, the shear modulus of the rock tends to zero, making it lose its rigidity and the rock falls apart. The classical homogenization schemes do not describe the mechanical properties of a rock near the critical porosity. The approach proposed here is based on the generalized differential effective medium (GDEM) method. We introduce a model of porous elastic media composed of an elastic solid host containing ellipsoidal inclusions of two types. Inclusions of the first type (phase 1) represent pores, and inclusions of the second type (phase 2) contain elastic solid material described by the same elastic properties as the host (phase 0). In this model, with an increase in porosity, the concentration of the host decreased, and it tended to zero near the critical porosity. The model was used for simulation of rock elastic moduli. We compared the modeling results for elastic moduli and acoustic velocities with the experimental data and empirical petrophysical equations. The comparison showed that the GDEM model describes the elastic properties behavior in a wide range of porosity up to the critical value.

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