Questions regarding how the brain interprets information from the eyes. Consider using the "eyes" tag for discussion of eye anatomy, physiology and evolution.

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Like size and colour constancy, why does the brain not maintain focus constancy?

I have progressive myopia. I grew up with perfectly normal eyes but slowly started getting myopic. The thing is, my brain knows (or should know) what the world looks like -- it knows that far away ...
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16 views

Dog with failing vision - how can we help [migrated]

Our border collie is getting old. Her eyes are beginning to fail and there are clear signs of cataracts. She seems to sometimes feel stressed when she encounters stripes of contrasting colours. ...
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0answers
28 views

Are some facial features more important than others in human facial recognition?

I'm often surprised by the human ability to correctly identify other individuals despite significant modifications due to ageing, hairstyle, injury etc. But, sometimes the addition of a beard and a ...
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3answers
213 views

Is human vision sensitive to frequency or wavelength?

In a vacuum, there is a one-to-one correspondence between light frequency ($\nu$) and wavelength ($\lambda$), ie. $\lambda=c/\nu$. But in a refractive medium, $\lambda=v/\nu$, so while the frequency ...
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1answer
62 views

How does myopia develop, exactly?

Recently I was reading about myopia and I understood a few basic facts about it: Its initial cause is a constant spasm in the ciliary muscle. To do less work, the eyeball elongates a tiny bit. ...
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1answer
40 views

Does Spinning dancer has anything to do with your eyesight

I came across the spinning dancer as part of the brain test to determine left brain vs right brain dominance. I saw the dancer is turning clockwise. The other people around me saw it turning ...
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1answer
2k views

What do you see when your eyes are closed?

If you are in pitch black and you close your eyes, you sometimes can see strange shapes of various colors. A lot of the time these shapes and colors change as you observe them. This phenomenon still ...
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2answers
64 views

Is mammalian vision processed as a sequence of frames?

I often read that people believe that human vision has an inherent frames-per-second rate (FPS) that causes stroboscopic effects - such as seeing the spokes of a rotating wheel apparently rotating at ...
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1answer
57 views

Can the negative afterimage appear only if there is light or is it possible in darkness?

Reading the following paragraph: After staring at the red and blue shamrock, you saw a green and yellow afterimage. Opponent-process theory proposes that as you stared at the red and blue ...
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1answer
890 views

Dark veil when getting up too fast

I was asking myself this weird question. When you get up or stand up too fast, sometimes, you see something like a dark veil, and you aren't able to see anything distinctly for 2 or 3 seconds, then ...
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1answer
87 views

How much energy is required to blind someone?

As I understand the ravages of sunlight upon the (human) eye; the cause of ocular damage and blindness is too much energy delivered to the cones and rods that ultimately make up our eyes; so the ...
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1answer
80 views

How does someone with red-green colorblindness see yellow on a monitor/television?

I recently watched the video This Is Not Yellow explaining how red, green, and blue pixels can be used to create images of all other colors. Since yellow is created with red and green pixels, how is a ...
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50 views

Are insects attracted to near infrared light?

Do insects see near infrared light? If yes, are they attracted to it at night, as they are to visible light sources? I am building something similar to a home-made trailcam with a Raspberry Pi ...
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1answer
30 views

What is the focus distance of a 3D screen?

I've thought long and hard about wheter this is the appropriate section for this question, because I guess it's kind of an interdisciplinary subject. My understanding of stereopsis (please, correct ...
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0answers
41 views

How well does the event-driven DVS sensor approximate the rods of the retina?

There is a neuromorphic vision sensor that is generating some interesting research these days that is called the Dynamic Vision Sensor. One of the claims of this sensor is good approximation of the ...
9
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1answer
164 views

Seeing strange things in light

I have noticed that if you look directly at tubelight (I have only white ones in my home) and close your eyes little, you see little random shaped colourless things sometimes with slow speed and ...
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2answers
75 views

Improving myopia

I have a friend who no longer needs glasses. He previously had myopia in both eyes but over the years it has improved until he no longer needs glasses clinically. He's had glasses for over 30 years ...
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0answers
54 views

Does our brain really “flip” images perceived by our eyes?

I know a similar question has been asked and this is closely related to cognitive science. However, I want to know whether is there any mechanism or structure in the visual cortex which is proved to ...
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0answers
313 views

The process of how you visually perceive objects?

Use the following terms to describe in detail how you visually perceive an object that you can see right now. Use the terms in order to correctly describe the sequence of events involved in your ...
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1answer
87 views

Dogs bark at familiar person in Santa costume. Why? Don't dogs trust smell over vision?

Last night 10 humans and 2 dogs spent Christmas together. At some point, one human dissappears for a few minutes and comes back wearing a full Santa outfit. Upon respawning, the dogs start barking ...
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0answers
80 views

How is color information transmitted from eye to brain?

Is it frequency-modualated or are different colors transmitted by different axons? I know that each ganglion cell is connected to multiple photoreceptors. How does it tell the brain which ...
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0answers
45 views

How well do we notice asynchronicity?

I'm stopped at a stoplight and, with nothing to do, my thoughts wander to the timed don't-walk sign that governs any pedestrians who might wish to cross the street I'm driving along. I can see two ...
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1answer
131 views

Why don't we have more cone cells (bigger fovea)?

Background Apart from being able to sense color, cone cells are able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. ...
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1answer
148 views

Haidinger's brush: Is this a by-product of the eye's physics, or are there any evolutionary grounds for it?

The human eye is, very subtly, sensitive to the polarization of light. This is an effect known as Haidinger's brush (see Wikipedia article of this name). What, if anything, is known or at least ...
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1answer
305 views

Is it safe to look at infrared LEDs?

What happens if one looks directly at infrared LEDs? Sometimes I see this kind of LED at night as red dots and I'm also courious about it. I was wondering what would happened if one looked directly ...
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1answer
63 views

Radial Basis Function Network (RBF Network)

In the Wikipedia article on radial basis function network, I didn't understand what was meant by "center vector for neuron i", in other words "center of the RBF units called also prototype".
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58 views

The Operation of tuning in the S1 layer of ventral model

According to my previous question in ventral Stream pathway and architecture, I want now to get a brief example about how the S1 layer is constructed. In other words, how all the simple units are ...
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1answer
179 views

Ventral stream pathway and architecture proposed by Poggio's group

Please can you give me a very brief explanation about all functions in the ventral stream architecture summarized in this figure: This figure is from Serre et al.'s A quantitative theory of ...
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3answers
2k views

What is the equivalent of shutter-speed in Human eye?

I just learned that in video cameras, every frame of the video has its own shutter speed. And I know how frame-rate in human eye works out, well, not completely, hence the question. ...
3
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2answers
142 views

Why do our eyes “wrap” hue from UV to IR?

On the high-wavelength side of things, we see almost-infrared as reddish, with a slight tinge of magenta. On the low side, we see violet fading into the same magenta color. Why is that? You can see ...
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1answer
134 views

Are there specific conditions that allow humans to see ultraviolet wavelengths

It is fairly common knowledge that the lens in its normal state absorbs ultraviolet (UV) radiation. An interesting notion has come up from time to time in my reading that suggests there are a small ...
4
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1answer
103 views

Was life less colorful before color vision evolved?

According to Wikipedia, we know that color-vision photopigments appeared in the common ancestors of tetrapods and fish at least 360 MY ago. Would life have been less colorful before the evolution of ...
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0answers
253 views

Reason for seeing grid-like patterns when strobing a solid black-white image?

I was trying to do some stimulation for SSVEPs by strobing a solid black square and a solid white square. Weird thing was, I ended up seeing weird grid like patterns that looked like this, always of ...
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1answer
148 views

If people with colorblindness lack one type of cone cells, shouldn't they be unable to recognize one particular color?

The 3 types of cone cells in normal humans allow them to view 3 types of colors and any color made from mixing and matching those 3. So, 2 types of cone cells should only allow to view just 2 types ...
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2answers
108 views

Do people with colorblindness have less cones or no cones of a certain type?

https://en.wikipedia.org/wiki/Color_blindness#Red.E2.80.93green_color_blindness Protanopia (1% of males): Lacking the long-wavelength sensitive retinal cones, Deuteranopia (1% of males): ...
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4answers
351 views

Are there animals which can see movements better than shapes or colors?

I remember that in Michael Crichton's novel Jurassic Park, Tyrannosaurus Rex was supposed to have movement based vision. (Of course, that is a novel and not a scientific text.) I have also noticed ...
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3answers
194 views

What exactly is the neural receptive field?

Neural receptive fields map the spatial or temporal distribution of the data to individual neuron excitation, if I understand correctly, but I do not understand if receptive fields (especially in the ...
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1answer
143 views

Are these claims of “revolutionising” understanding of human vision and hearing valid?

I've started a hobby machine vision project (and posted some questions to this end on other SE sites) and on a side track, also been looking at relevant research in human vision (and partly, hearing). ...
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1answer
9k views

What is it called when one human eye is seeing brighter color than the other?

What is the name of a phenomenon where one of the human eyes is seeing brighter/more saturated color than the other? I can observe the same object from the same position while alternating which eye is ...
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1answer
74 views

Animal UV vision

It is reasonably well known that many species, such as bees and some types of birds as examples can see into the ultraviolet (UV). How is the structure of their eye different to humans to allow this? ...
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1answer
45 views

The Eye, and Camera Lenses

How do near sightedness, farsightedness, and normal sightedness work? If the eye is accustomed to one small focal point, how can it manage a wall of light? And also, how does it process the small ...
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0answers
35 views

What processes are responsible for focusing on an image only seen by one of the eyes?

When a person is spying from around a corner with only one eye, it's rather easy to ignore the other eye's image, since it's probably much darker, because one usually spies around a corner standing ...
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1answer
165 views

Why are trichromat cone cells unable to sense ultraviolet and infrared radiation?

I understand that cone cells vary in the color they sense, is this because of wavelength, frequency, something else, or a combination of the previous? I also understand that tetrachromats can see an ...
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2answers
148 views

What gives observable light its colors? [duplicate]

I know that difference between different colors of light is difference between their wave length but I don't know what gives beautiful colors (like rainbow colors) to different wave length of ...
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0answers
123 views

Perception of distant lights without glasses

I am fairly short-sighted and wear glasses pretty much all the time. Naively, I would expect that when I take my glasses off, the image I see should look very much the same as as a photograph that's ...
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3answers
168 views

Is it technically possible to make someone see something when their eyes are closed?

I'm writing a little article and need any information about how human vision works and latest technologies and discoveries around. Actually its not a professional article. Its for a group of my ...
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1answer
236 views

What is the brightest color a light source that only emits blue frequency light can achieve?

Let's say there is a luminous light bulb that only emits blue light, and you (or a camera if you prefer) look at it from a close distance. Will the maximum brightness perceived not have any "white" to ...
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1answer
73 views

Is there an optimal illumination level for human habitats/workplaces?

I know of melanopsin, a photo pigment in mammal eye that helps regulate circadian rhythms. It responds most strongly to blue spectrum light. There have been experiments that demonstrated that ...
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3answers
841 views

What is the difference between a circular and a cat's-eye pupil?

I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on ...
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1answer
56 views

HSL Lightness vs Eye sensitivity

In a monochromatic spectrum, is the human eye equally able to distinguish between lighter colors just as it is in distinguishing between darker colors? I mean is there really a linear relationship ...