scholarly journals Influence of artificially generated interocular blur difference on fusion stability under vergence stress

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Miroslav Dostalek ◽  
Jan Hejda ◽  
Karel Fliegel ◽  
Michaela Duchackova ◽  
Ladislav Dusek ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Healthy Subjects ◽  
Luminance Contrast ◽  
Natural Scenes ◽  
Frequency Content ◽  
Binocular Fusion ◽  
Dominant Eye ◽  
Blurred Image ◽  
The Stability ◽  
Mode A

The stability of fusion was evaluated by its breakage when interocular blur differences were presented under vergence demand to healthy subjects. We presumed that these blur differences cause suppression of the more blurred image (interocular blur suppression, IOBS), disrupt binocular fusion and suppressed eye leaves its forced vergent position. During dichoptic presentation of static grayscale images of natural scenes, the luminance contrast (mode B) or higher-spatial frequency content (mode C) or luminance contrast plus higher-spatial frequency content (mode A) were stepwise reduced in the image presented to the non-dominant eye. We studied the effect of these types of blur on fusion stability at various levels of the vergence demand. During the divergence demand, the fusion was disrupted  with approximately half blur than during convergence. Various modes  of blur influenced fusion differently. The mode C (isolated reduction of higher-spatial frequency content) violated fusion under the lowest vergence demand significantly more than either isolated or combined reduction of luminance contrast (mode B and A). According to our results, the image´s details (i.e. higher-spatial frequency content) protects binocular fusion from disruption by the lowest vergence demand.

Neuronal response to texture- and contrast-defined boundaries in early visual cortex

2007 ◽  
Vol 24 (1) ◽  
pp. 65-77 ◽  
Author(s):  
YUNING SONG ◽  
CURTIS L. BAKER
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Cortical Neurons ◽  
Visual Cues ◽  
Neuronal Response ◽  
Luminance Contrast ◽  
Movement Direction ◽  
Natural Scenes ◽  
Neural Responses ◽  
Early Visual Cortex

Natural scenes contain a variety of visual cues that facilitate boundary perception (e.g., luminance, contrast, and texture). Here we explore whether single neurons in early visual cortex can process both contrast and texture cues. We recorded neural responses in cat A18 to both illusory contours formed by abutting gratings (ICs, texture-defined) and contrast-modulated gratings (CMs, contrast-defined). We found that if a neuron responded to one of the two stimuli, it also responded to the other. These neurons signaled similar contour orientation, spatial frequency, and movement direction of the two stimuli. A given neuron also exhibited similar selectivity for spatial frequency of the fine, stationary grating components (carriers) of the stimuli. These results suggest that the cue-invariance of early cortical neurons extends to different kinds of texture or contrast cues, and might arise from a common nonlinear mechanism.

From spatial frequency contrast to edge preponderance: the differential modulation of early visual evoked potentials by natural scene stimuli

2011 ◽  
Vol 28 (3) ◽  
pp. 221-237 ◽  
Author(s):  
BRUCE C. HANSEN ◽  
THEODORE JACQUES ◽  
AARON P. JOHNSON ◽  
DAVE ELLEMBERG
Keyword(s):  
Spatial Frequency ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Luminance Contrast ◽  
Systematic Investigation ◽  
Natural Scenes ◽  
Natural Scene ◽  
Sinusoidal Gratings ◽  
Edge Content ◽  
Visual Evoked

AbstractThe contrast response function of early visual evoked potentials elicited by sinusoidal gratings is known to exhibit characteristic potentials closely associated with the processes of parvocellular and magnocellular pathways. Specifically, the N1 component has been linked with parvocellular processes, while the P1 component has been linked with magnocellular processes. However, little is known regarding the response properties of the N1 and P1 components during the processing and encoding of complex (i.e., broadband) stimuli such as natural scenes. Here, we examine how established physical characteristics of natural scene imagery modulate the N1 and P1 components in humans by providing a systematic investigation of component modulation as visual stimuli are gradually built up from simple sinusoidal gratings to highly complex natural scene imagery. The results suggest that the relative dominance in signal output of the N1 and P1 components is dependent on spatial frequency (SF) luminance contrast for simple stimuli up to natural scene imagery possessing few edges. However, such a dependency shifts to a dominant N1 signal for natural scenes possessing abundant edge content and operates independently of SF luminance contrast.

Visual Memory for Objects in Natural Scenes: From Fixations to Object Files

2005 ◽  
Vol 58 (5) ◽  
pp. 931-960 ◽  
Author(s):  
Benjamin W. Tatler ◽  
Iain D. Gilchrist ◽  
Michael F. Land
Keyword(s):  
Real World ◽  
Visual Memory ◽  
Natural Scenes ◽  
Position Information ◽  
Object Property ◽  
Immediate Recall ◽  
Object Files ◽  
Stability Data ◽  
The Stability ◽  
Types Of Information

Object descriptions are extracted and retained across saccades when observers view natural scenes. We investigated whether particular object properties are encoded and the stability of the resulting memories. We tested immediate recall of multiple types of information from real-world scenes and from computer-presented images of the same scenes. The relationship between fixations and properties of object memory was investigated. Position information was encoded and accumulated from multiple fixations. In contrast, identity and colour were encoded but did not require direct fixation and did not accumulate. In the current experiments, participants were unable to recall any information about shape or relative distances between objects. In addition, where information was encoded we found differential patterns of stability. Data from viewing real scenes and images were highly consistent, with stronger effects in the real-world conditions. Our findings imply that object files are not dependent upon the encoding of any particular object property and so are robust to dynamic visual environments.

scholarly journals Laterality and (in)visibility in emotional face perception: Manipulations in spatial frequency content.

Emotion ◽  
2019 ◽  
Author(s):  
Markus Hausmann ◽  
Bobby R. Innes ◽  
Yan K. Birch ◽  
Robert W. Kentridge
Keyword(s):  
Spatial Frequency ◽  
Face Perception ◽  
Frequency Content ◽  
Emotional Face

scholarly journals The effect of spatial frequency content on parameters of eye movements

2008 ◽  
Vol 72 (6) ◽  
pp. 601-608 ◽  
Author(s):  
Marina T. Groner ◽  
Rudolf Groner ◽  
Adrian von Mühlenen
Keyword(s):  
Eye Movements ◽  
Spatial Frequency ◽  
Frequency Content

Natural scenes have matched amplitude-modulated sounds that systematically influence visual scanning

2012 ◽  
Vol 25 (0) ◽  
pp. 121
Author(s):  
Marcia Grabowecky ◽  
Aleksandra Sherman ◽  
Satoru Suzuki
Keyword(s):  
Eye Movements ◽  
Spatial Frequency ◽  
Memory Task ◽  
High Spatial Frequency ◽  
Visual Object ◽  
Natural Scenes ◽  
Scale Invariant ◽  
Visual Coding ◽  
Visual Spatial ◽  
Spatial Frequencies

We have previously demonstrated a linear perceptual relationship between auditory amplitude-modulation (AM) rate and visual spatial-frequency using gabors as the visual stimuli. Can this frequency-based auditory–visual association influence perception of natural scenes? Participants consistently matched specific auditory AM rates to diverse visual scenes (nature, urban, and indoor). A correlation analysis indicated that higher subjective density ratings were associated with faster AM-rate matches. Furthermore, both the density ratings and AM-rate matches were relatively scale invariant, suggesting that the underlying crossmodal association is between visual coding of object-based density and auditory coding of AM rate. Based on these results, we hypothesized that concurrently presented fast (7 Hz) or slow (2 Hz) AM-rates might influence how visual attention is allocated to dense or sparse regions within a scene. We tested this hypothesis by monitoring eye movements while participants examined scenes for a subsequent memory task. To determine whether fast or slow sounds guided eye movements to specific spatial frequencies, we computed the maximum contrast energy at each fixation across 12 spatial frequency bands ranging from 0.06–10.16 cycles/degree. We found that the fast sound significantly guided eye movements toward regions of high spatial frequency, whereas the slow sound guided eye movements away from regions of high spatial frequency. This suggests that faster sounds may promote a local scene scanning strategy, acting as a ‘filter’ to individuate objects within dense regions. Our results suggest that auditory AM rate and visual object density are crossmodally associated, and that this association can modulate visual inspection of scenes.

Three-dimensional stability analysis for a salt-finger convecting layer

2018 ◽  
Vol 841 ◽  
pp. 636-653
Author(s):  
Ting-Yueh Chang ◽  
Falin Chen ◽  
Min-Hsing Chang
Keyword(s):  
Stability Analysis ◽  
Three Dimensional ◽  
Longitudinal Mode ◽  
Transverse Mode ◽  
Solute Diffusion ◽  
Two Dimensional ◽  
Grashof Number ◽  
Significant Difference ◽  
The Stability ◽  
Mode A

A three-dimensional linear stability analysis is carried out for a convecting layer in which both the temperature and solute distributions are linear in the horizontal direction. The three-dimensional results show that, for $Le=3$ and 100, the most unstable mode occurs invariably as the longitudinal mode, a vortex roll with its axis perpendicular to the longitudinal plane, suggesting that the two-dimensional results are sufficient to illustrate the stability characteristics of the convecting layer. Two-dimensional results show that the stability boundaries of the transverse mode (a vortex roll with its axis perpendicular to the transverse plane) and the longitudinal modes are virtually overlapped in the regime dominated by thermal diffusion and the regime dominated by solute diffusion, while these two modes hold a significant difference in the regime the salt-finger instability prevails. More precisely, the instability area in terms of thermal Grashof number $Gr$ and solute Grashof number $Gs$ is larger for the longitudinal mode than the transverse mode, implying that, under any circumstance, the longitudinal mode is always more unstable than the transverse mode.

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