Questions tagged [vision]
For questions regarding the visual system, which serves to transduce light energy into neural impulses, or regarding visual perception, how we interpret such incoming visual information.
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Is there any evidence for a bias towards perceiving darker surfaces as 'figure' rather than 'ground'?
Given that surfaces which capture attention are more likely to be perceived as figures (or figures attract attention more than ground does?), is there a bias associated with the luminance of a surface?...
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Does the retina contribute in distinguishing lines and borders?
I think there is a phenomenon behind the way which our eyes judge between lines of contrast, like black lines on a white page, by just recognizing the contrast areas at the level of the rods and cones....
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When your two eyes disagree sharply
Now and then, the image from each eye is so different from the other that it seems the brain has trouble combining them into a coherent image. You can create this situation by putting a hand or sheet ...
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Convolutional Operations in the Visual Cortex
One of the fundamental operations in image neural networks is the operation of convolution, where a filter slides across the receptive field, activating on particular features. This is incredibly ...
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If the color black reflects no light, how are we able to see it?
If color as we perceive it is dependent on the wave lengths that are reflected by an object, with white reflecting all hues and black absorbing all, how do we detect a black object?
I do understand ...
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Ability to identify an "average" vs a maximum (or minimum)?
I have a hypothesis that humans are better able to identify the largest (or smallest) in a set of objects, compared to their ability to identify an average object, i.e. the one closest to the mean.
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What is the cause of differences that are too small to see?
Consider two identical pieces of paper.
Scenario 1: On both something is drawn in black ink. If the difference between the areas covered in black ink is sufficiently small, I cannot see the ...
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Mental rotation test in a virtual environment
Parsons et al. (2004) found that the widely reported sex difference in performance in the pen-and-paper mental rotation test could not be reproduced in a virtual environment:
The visuospatial ...
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How do different emotional intensity ratings within a condition influence the comparison across different conditions in an event-related fMRI task?
I'm planning an event-related fMRI-experiment to investigate the difference in processing natural and computer-generated expressions. For this, we recorded videos of 4 different actors posing fearful ...
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To what extent is face-detection achieved in peripheral vision?
I'm trying to find out to what extent mere detection of faces (i.e. determining that something is a face, as opposed to recognition of specific individuals) is favored in the central vision vs ...
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How can schemas be applied to website design? [closed]
If a "schema is a cognitive framework or concept that helps organize and interpret information. Schemas can be useful because they allow us to take shortcuts in interpreting the vast amount of ...
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Is V1 involved in visual imagery?
It's well known that mental imagery shares the neural substrates of its respective modality, despite dissociable multivariate patterns. For example, visual imagery can be decoded across the ventral ...
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Is the Rubin Vase illusion an example of inattentional blindness?
Generally, people looking at an example of a Rubin Vase see either the vase, or the faces. The brain seems to make a decision on which one is being viewed, but both cannot be focused-on at the same ...
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Region of Interest Proposal in Vision
In machine learning, Region of Interest (ROI) proposal is a method for subsampling an image to identify "interesting" subregions. A canonical example is from Region Convolutional Neural Networks, ...
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What electrical stimuli do brain implants use?
I was reading about artificial eyes and came to think about how the brain works. More specifically, what "signals" it uses in the case of cortical visual prosthetics in blind people? Cortical ...
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Learning In Retina
Most of the sources studying retina seem to suggest that retinal connectome is hardwired and species dependent (like specialized vertical movement detector in small rodents). I couldn't find a single ...
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What are the definitions of 'multi-channel coding' and 'opponent channel coding'?
I am looking for the definitions of
Multi-channel coding
Opponent-channel coding
And specifically in the context of visual adaptation. I have searched for information on the web and in books, but ...
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Is there a waterfall visual after-effect with discrete inputs?
If you watch a waterfall for several seconds and then suddenly change your gaze to a fixed object it appears to briefly move upward.
But if instead you're looking at a scrolling LED marquee sign, ...
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Are the receptive fields of bipolar and retinal ganglion cells directly stimulated by light?
I know this is a basic question, but I can't find the answer anywhere. How can a cell that is not photoreceptive (eg LGN and retinal gangion cells) have a receptive field that is stimulated by "light" ...
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Use of the visual cortex in mathematical thinking?
In modern computers (and programming) one makes alienated use of the high powers of graphical processing units (GPU) for non-graphics-related tasks, enhancing drastically the power of the general ...
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How bright must a light bulb to be noticed in a room?
If one has say an 800 lumen bulb, how many lux are necessary in order for a human to detect when it's suddenly turned on in a room with brightness levels of
30 Lux
50 Lux
100 Lux
1.-How many Lux ...
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Grating orientation & frequency which induces highest gamma
I am doing some research on perception and gamma activity in V1 area.
To check some of my results I need to find an experimental result, from which I would know which orientations and frequencies of ...
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Random-dot kinematograms implementation in javascript/HTML
I am looking for a "random-dot kinematograms" implementation in javascript/HTML that I can use in web-based experiments. Something like this, where the user can specify the direction using a mouse or ...
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Progress on Arnheim's perceptual forces in vision
In the second edition of Rudolf Arnheim's Art and Visual Perception: A Psychology of the Creative Eye, published in 1974, (Google Books Preview available here) the opening chapter on "balance&...
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What explains the characteristics of the receptive fields of simple cells in V1?
Here is a YouTube video of a Hubel & Wiesel experiment from 1965 in the visual cortex. The video shows the experimenters outlining the receptive field of a simple cell in the first part of the ...
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Is habituation responsible for inaccurate airport security screenings?
The U.S. Transportation Security Administration has "red teams" who try to sneak dangerous items through airport security. The security personnel often fail up to 95% of these tests. Is this high ...
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What happens in my retina if I press on my eyeballs?
If I press my eyes I can "see" all kind of things: sparkling blue dots (which sometimes seem random and sometimes there seems to be a pattern in them), growing or diminishing rings of all kinds of ...
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Is cortical magnification in the visual system related to synaptic pruning, or is it a separate developmental or learning process?
I'm primarily interested in learning about current computational models that explain cortical magnification in the visual system.
With this in mind, my specific questions are: (1) Is this phenomenon ...
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Can color blindness be treated with image filtering technology?
Using image color-filtering techniques we can simulate the way colorblind people see:
The aim of this question is to know whether the opposite process could be possible, namely can a colorblind ...
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What timing of visual emphasis paired with a spoken word provides the best cognition? [closed]
I am working on an animation in which there are three somewhat small font words (Environmental, Social, and Economic) together with three colored horizontal histogram bars on each side of the labels ...
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Can we learn to adapt to image-reversal when being intermittently exposed to them?
I know that human vision can get accustomed to reverse vision when wearing reverse glasses for several days. But does it work when we see the reverse image just in certain moments throughout the day? ...
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What is the neural adaptation underlying the habituation to reversed visual images? [closed]
When a person wears glasses that reverse the image upside-down, it is possible to adjust your vision in a matter of days. What are the suggestions behind the neurological process?
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How is the biological error signal in predictive coding computed?
I am quite inspired by the results obtained by PredNet, which implements a predictive coding model using artificial neural networks. They compute the prediction error as a simple subtraction, and then ...
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Why is white on black considered higher contrast than black on white?
While researching to answer Why are "Inverted Colors" considered an accessibility feature? I noticed the puzzling claim that "White text on a black background is a higher contrast to the opposite, so ...
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Do we perceive contrast colour patterns easily because of adaptation?
I can understand that colours are just manipulation of our brain to light rays of different wavelength and energy. We perceive patterns better at higher contrast. Do we perceive patterns better at ...
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How do mammals estimate the speed of moving objects?
Has there been any research on how mammals predict the speed of moving objects? In particular, how do they integrate top-down information? For instance, do they have greater difficulty estimating the ...
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Are we able to simulate pain through the brain?
I have like 0 experience or knowledge about brain signals and all that stuff but I'm curious about how much we know about the brain in terms of like tricking your brain that with simulation of pain. ...
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What do you call sensations without stimuli?
Sometimes, when you close your eyes in the dark, you see what looks like sparks or flashes. Sometimes when you are tired, your vision seems to shift sideways and realign, like someone bumped into a ...
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Do direct cortical pathways exist in the visual system, or do they all go via the thalamus?
Do visual cortical signals always go back and forth between the thalamus, or other subcortical structures, or can they travel directly from one region in the cortex to another?
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What is the difference between apparent motion and apparent movement?
A definition for apparent movement is:
The perception of movement produced by stimuli that are stationary but are presented first at one position and then, at an appropriate time interval, presented ...
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Does the strength of the simultaneous contrast illusion vary with the length of time it is viewed?
I have done several searches without finding any papers addressing this question..
I'd like to know if there is any evidence to suggest that the strength of the simultaneous contrast illusion (or any ...
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Model of human estimation of correlation tasks
I am looking for a model (bayesian or not) on how people would estimate the correlation between two variables from a given scatter plot. Any one knows of such model?
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How is the focal point determined when looking into a clear sky?
When looking into a clear blue sky, no cloud, birds, trees or any object to give a frame of reference. When a person is actively looking, as opposed to day dreaming or gazing.
The sky goes for a long ...
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How common is it for twins conjoined at the head to share thoughts and visual stimuli?
I've always been interested in the possibility of a pair of conjoined twins, joined at the head, being able to read each other's thoughts, react to stimuli that one of them can't see/hear/feel, and ...
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What are the effects of visual deprivation on mental health and the other senses?
How do blind people who haven't always been visually impaired deal with their day-to-day lives? I've heard rumors (very, very unreliable rumors) that once you stay in the dark for too long you'll ...
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How image orientation influences perception
Im a painter for many years. When I paint, I usually walk around and look at my painting for many hours. When painting session is long, it harder and harder to maintain a "fresh look".
By fresh look; ...
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What is the difference between 'stereoscopic depth' and 'crossed/uncrossed disparity'?
What is the difference between stereoscopic depth and crossed/uncrossed disparity, and specifically in terms of their use in the methods to manipulate visual stimuli to investigate depth-perception?
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Is prior experience necessary to perceive the Kanizsa triangle illusion?
We know the Kanizsa Triangle.
Kanizsa Triangle
I was socialized in a "western" world, where I learned mathematics for about 13 years; I have designed products surrounding me using geometric forms ...
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Why can't hemineglect patients be trained to actively pay attention to their neglected side?
I'm still having a hard time understanding the symptoms of hemineglect, mainly because perception and attention has been two peas of a pod for most of my experiences.
A Scholarpedia article states ...
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What is the relationship between visual attention network and visual stream (Two-streams hypothesis)?
There are two visual attention networks proposed by Maurizio Corbetta and Gordon L. Shulman (2002). These are top-down and bottom-up attention networks.
One system, which includes parts of the ...
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