scholarly journals Spatial frequency spectra of random dynamic glass patterns predict perceived motion direction

2010 ◽  
Vol 7 (9) ◽  
pp. 1008-1008
Author(s):  
L. Bowns ◽  
H. Barlow
Keyword(s):  
Spatial Frequency ◽  
Motion Direction ◽  
Frequency Spectra ◽  
Glass Patterns ◽  
Perceived Motion

scholarly journals The interaction between orientation and motion signals in moving oriented Glass patterns

2017 ◽  
Vol 34 ◽  
Author(s):  
ANDREA PAVAN ◽  
LUCY M. BIMSON ◽  
MARTIN G. GALL ◽  
FILIPPO GHIN ◽  
GEORGE MATHER
Keyword(s):  
Excitatory Input ◽  
Motion Sensors ◽  
Motion Information ◽  
Spatial Motion ◽  
Dipole Orientation ◽  
Motion Direction ◽  
Oriented Texture ◽  
Orientation Information ◽  
Glass Patterns ◽  
Perceived Motion

AbstractPrevious psychophysical evidence suggests that motion and orientation processing systems interact asymmetrically in the human visual system, with orientation information having a stronger influence on the perceived motion direction than vice versa. To investigate the mechanisms underlying this motion-form interaction we used moving and oriented Glass patterns (GPs), which consist of randomly distributed dot pairs (dipoles) that induce the percept of an oriented texture. In Experiment 1 we varied the angle between dipole orientation and motion direction (conflict angle). In separate sessions participants either judged the orientation or motion direction of the GP. In addition, the spatiotemporal characteristics of dipole motion were manipulated as a way to limit (Experiment 1) or favor (Experiment 2) the availability of orientation signals from motion (motion streaks). The results of Experiment 1 showed that apparent GP motion direction is attracted toward dipole orientation, and apparent GP orientation is repulsed from GP motion. The results of Experiment 2 showed stronger repulsion effects when judging the GP orientation, but stronger motion streaks from the GP motion can dominate over the signals provided by conflicting dipole orientation. These results are consistent with the proposal that two separate mechanisms contribute to our perception of stimuli which contain conflicting orientation and motion information: (i) perceived GP motion is mediated by spatial motion-direction sensors, in which signals from motion sensors are combined with excitatory input from orientation-tuned sensors tuned to orientations parallel to the axis of GP motion, (ii) perceived GP orientation is mediated by orientation-tuned sensors which mutually inhibit each other. The two mechanisms are revealed by the different effects of conflict angle and dipole lifetime on perceived orientation and motion direction.

scholarly journals Theory of the perceived motion direction of equal-spatial-frequency plaid stimuli.

2020 ◽  
Vol 127 (3) ◽  
pp. 305-326
Author(s):  
George Sperling ◽  
Peng Sun ◽  
Dantian Liu ◽  
Ling Lin
Keyword(s):  
Spatial Frequency ◽  
Motion Direction ◽  
Perceived Motion

scholarly journals Theoretical predictions of the perceived motion-direction of same-spatial-frequency plaids

2019 ◽  
Vol 19 (10) ◽  
pp. 167a
Author(s):  
George Sperling ◽  
Dantian T. Liu ◽  
Peng Sun ◽  
Ling Lin
Keyword(s):  
Spatial Frequency ◽  
Motion Direction ◽  
Theoretical Predictions ◽  
Perceived Motion

scholarly journals A new variant of the barberpole effect: Psychophysical data and computer simulations

Psihologija ◽  
2002 ◽  
Vol 35 (3-4) ◽  
pp. 209-223
Author(s):  
Dejan Todorovic
Keyword(s):  
Receptive Fields ◽  
Vertical Component ◽  
Parallel Line ◽  
Random Fluctuation ◽  
Final State ◽  
Motion Direction ◽  
Weak Preference ◽  
New Variant ◽  
Direction Sensitivity ◽  
Perceived Motion

The classic barberpole effect shows that perceived direction of motion of parallel line segments depends on the orientation of the frame defined by segment end points. A stimulus configuration was created by crossing two oblique barberpoles. Perceived motion in the crossed portion of the configuration is bi-stable, alternating between two oblique directions defined by the two component barberpoles. Ratings of dominance of perceived motion direction in the crossed portion of two barberpoles of different width and orientation revealed a strong preference for the wider component barberpole and a weak preference for the nearer-to-vertical component barberpole. A network model is presented in which each unit inhibits units with different direction sensitivity and co-extensive receptive fields, and excites units with equal direction sensitivity and neighboring receptive fields. Simulations of the temporal evolution of the spatial activity profile exhibit the effect of barberpole width and the bi-stability of percepts. Fatigue of highly adapted units enables the gradual emergence of non-adapted units. Small initial variations can lead to profound differences in the final state of the system, explaining the quasi-random fluctuation between the two perceptual variants.

scholarly journals Two-Dimensional Spatial Frequency Content and Confusions among Dot Matrix Characters

1979 ◽  
Vol 23 (1) ◽  
pp. 384-388
Author(s):  
Michael E. Maddox
Keyword(s):  
Spatial Frequency ◽  
Similarity Measure ◽  
Similarity Measures ◽  
Final Analysis ◽  
Second Phase ◽  
Two Dimensional ◽  
Two Phase ◽  
Frequency Spectra ◽  
Character Size ◽  
Point Fast Fourier Transform

A two-phase study was conducted which related the confusions among dot matrix characters to the two-dimensional spatial frequency similarity of these characters. During the first phase of the study, subjects were shown single alphanumeric characters from four different dot matrix fonts and five matrix size/character sub-tense combinations. Data from this phase of the research were analyzed in terms of both correctness and character confusion frequencies. The second phase of the study consisted of digitizing and analyzing all characters from two of the fonts used in the first phase. The fonts chosen represent the most and least confusable of the four, based on the performance data obtained. These characters were scanned photometrically using a computer-controlled X-Y stage and subjected to a 512 × 512 point fast Fourier transform (FFT). The Fourier coefficients were correlated for all possible character pairs within each font-matrix/character size cell. These correlations provided an objective similarity measure among characters based upon their 2-D spatial frequency spectra. In addition to the spatial frequency similarity measure, a simple digital Phi coefficient was calculated for each character pair. The final analysis performed in this study was the correlation of observed performance (confusions) with objective similarity measures (2-D spectra and Phi coefficients).

Resolving Power and the Detection of Linear Detail

1965 ◽  
Vol 19 (2) ◽  
pp. 190-205 ◽  
Author(s):  
W. N. Charman
Keyword(s):  
Transfer Function ◽  
Spatial Frequency ◽  
Resolving Power ◽  
Optical Transfer Function ◽  
Simple Relationship ◽  
Frequency Spectra ◽  
Optical Transfer

The ability of a photographic system to resolve and detect linear details is discussed in terms of the spatial frequency spectra of the details, the optical transfer function of the system and the threshold of the detector used with the system. It is shown that there is no simple relationship between the resolving power of the system and the size of the linear detail that the system is capable of detecting.

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