Quantitative Studies of Some Dynamic Visual Effects

Perception ◽  
1980 ◽  
Vol 9 (3) ◽  
pp. 303-316 ◽  
Author(s):  
John L Barbur
Keyword(s):  
Visual Processing ◽  
Periodic Structures ◽  
Early Stage ◽  
Temporal Integration ◽  
Angular Speed ◽  
Physiological Data ◽  
One Dimensional ◽  
Quantitative Studies ◽  
Anticlockwise Rotation ◽  
Element Movement

The viewing of rotating or rapidly approaching one-dimensional periodic structures results in the perception of a high-contrast band on a uniform structureless surround. For rotating gratings, the width of the generated band is inversely proportional to the angular speed of rotation and the orientation of the band lags behind the direction perpendicular to the grating lines for both clockwise and anticlockwise rotation of the pattern. The amount of lag is proportional to the angular speed of rotation. The width of the band perceived during the viewing of an approaching or receding grating is inversely proportional to its speed, and the orientation of the generated band is along the direction of the lines in the grating. A model is proposed which explains and predicts the effects observed during the viewing of one-dimensional periodic structures in terms of temporal luminance integration in the visual system. The extent to which temporal luminance integration is responsible for the perception of frame or element movement in multielement stimulus frames is also examined. The results obtained with monocularly or dichoptically presented multielement stimulus frames, as well as other relevant psychophysical and physiological data, suggest that the temporal integration responsible for the observed effects is associated with mechanisms of early-stage visual processing which must be located prior to the lateral geniculate nucleus level.

Anomalous phase in one-dimensional, multilayer, periodic structures with birefringent materials

2004 ◽  
Vol 70 (16) ◽  
Author(s):  
A. Mandatori ◽  
C. Sibilia ◽  
M. Bertolotti ◽  
S. Zhukovsky ◽  
J. W. Haus ◽  
...  
Keyword(s):  
Periodic Structures ◽  
One Dimensional

Computing with Self-Excitatory Cliques: A Model and an Application to Hyperacuity-Scale Computation in Visual Cortex

1999 ◽  
Vol 11 (1) ◽  
pp. 21-66 ◽  
Author(s):  
Douglas A. Miller ◽  
Steven W. Zucker
Keyword(s):  
Visual Processing ◽  
Network Architecture ◽  
Early Stage ◽  
Cortical Cell ◽  
Pyramidal Cells ◽  
Direct Calculation ◽  
Formal Theory ◽  
Cortical Cells ◽  
Cell Counts ◽  
Spatiotemporal Response

We present a model of visual computation based on tightly inter-connected cliques of pyramidal cells. It leads to a formal theory of cell assemblies, a specific relationship between correlated firing patterns and abstract functionality, and a direct calculation relating estimates of cortical cell counts to orientation hyperacuity. Our network architecture is unique in that (1) it supports a mode of computation that is both reliable and efficent; (2) the current-spike relations are modeled as an analog dynamical system in which the requisite computations can take place on the time scale required for an early stage of visual processing; and (3) the dynamics are triggered by the spatiotemporal response of cortical cells. This final point could explain why moving stimuli improve vernier sensitivity.

The “Mosaic Stage” in Amodal Completion as Characterized by Magnetoencephalography Responses

2006 ◽  
Vol 18 (8) ◽  
pp. 1394-1405 ◽  
Author(s):  
Gijs Plomp ◽  
Lichan Liu ◽  
Cees van Leeuwen ◽  
Andreas A. Ioannides
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Early Stage ◽  
Amodal Completion ◽  
Peak Latency ◽  
Per Se

We investigated the process of amodal completion in a same-different experiment in which test pairs were preceded by sequences of two figures. The first of these could be congruent to a global or local completion of an occluded part in the second figure, or a mosaic interpretation of it. We recorded and analyzed the magnetoencephalogram for the second figures. Compared to control conditions, in which unrelated primes were shown, occlusion and mosaic primes reduced the peak latency and amplitude of neural activity evoked by the occlusion patterns. Compared to occlusion primes, mosaic ones reduced the latency but increased the amplitude of evoked neural activity. Processes relating to a mosaic interpretation of the occlusion pattern, therefore, can dominate in an early stage of visual processing. The results did not provide evidence for the presence of a functional “mosaic stage” in completion per se, but characterize the mosaic interpretation as a qualitatively special one that can rapidly emerge in visual processing when context favors it.

scholarly journals A Parameter Study of Localization

1996 ◽  
Vol 3 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sandor Stephen Mester ◽  
Haym Benaroya
Keyword(s):  
Periodic Structures ◽  
Numerical Study ◽  
Vibration Characteristics ◽  
Periodic Pattern ◽  
Parameter Study ◽  
Structural Damping ◽  
One Dimensional

Extensive work has been done on the vibration characteristics of perfectly periodic structures. Disorder in the periodic pattern has been found to lead to localization in one-dimensional periodic structures. It is important to understand localization because it causes energy to be concentrated near the disorder and may cause an overestimation of structural damping. A numerical study is conducted to obtain a better understanding of localization. It is found that any mode, even the first, can localize due to the presence of small imperfections.

scholarly journals Periodic and Near-Periodic Structures

1995 ◽  
Vol 2 (1) ◽  
pp. 69-95 ◽  
Author(s):  
S. S. Mester ◽  
H. Benaroya
Keyword(s):  
State Physics ◽  
Solid State ◽  
Periodic Structures ◽  
Vibration Characteristics ◽  
Aerospace Engineering ◽  
Structural Damping ◽  
Solid State Physics ◽  
One Dimensional ◽  
Fields Of Study ◽  
Effects Of Disorder

Extensive work has been done on the vibration characteristics of perfectly periodic structures. This article reviews the different methods of analysis from several fields of study, for example solid-state physics and civil, mechanical, and aerospace engineering, used to determine the effects of disorder in one-dimensional (1-D) and 2-D periodic structures. In the work examined, disorder has been found to lead to localization in 1-D periodic structures. It is important to understand localization because it causes energy to be concentrated near the disorder and may cause an overestimation of structural damping. The implications of localization for control are also examined.

scholarly journals Visual attention spreads broadly but selects information locally

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Satoshi Shioiri ◽  
Hajime Honjyo ◽  
Yoshiyuki Kashiwase ◽  
Kazumichi Matsumiya ◽  
Ichiro Kuriki
Keyword(s):  
Visual Attention ◽  
Spatial Attention ◽  
Visual Processing ◽  
Early Stage ◽  
Event Related Potential ◽  
Spatial Spread ◽  
Local Selection ◽  
Unified View ◽  
Behavioral Evidence ◽  
P3 Component

Abstract Visual attention spreads over a range around the focus as the spotlight metaphor describes. Spatial spread of attentional enhancement and local selection/inhibition are crucial factors determining the profile of the spatial attention. Enhancement and ignorance/suppression are opposite effects of attention, and appeared to be mutually exclusive. Yet, no unified view of the factors has been provided despite their necessity for understanding the functions of spatial attention. This report provides electroencephalographic and behavioral evidence for the attentional spread at an early stage and selection/inhibition at a later stage of visual processing. Steady state visual evoked potential showed broad spatial tuning whereas the P3 component of the event related potential showed local selection or inhibition of the adjacent areas. Based on these results, we propose a two-stage model of spatial attention with broad spread at an early stage and local selection at a later stage.

Pulsed second-harmonic generation in nonlinear, one-dimensional, periodic structures

1997 ◽  
Vol 56 (4) ◽  
pp. 3166-3174 ◽  
Author(s):  
M. Scalora ◽  
M. J. Bloemer ◽  
A. S. Manka ◽  
J. P. Dowling ◽  
C. M. Bowden ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Periodic Structures ◽  
Second Harmonic ◽  
One Dimensional
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