Questions tagged [vision]

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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0answers
26 views

Do animals with very small eyes see microscopic objects?

I understand that many small creatures have very elementary eyes: they are not scaled-down versions of the human eye but as I understand it often just light-sensitive organs for detecting movement. ...
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Are humans more adapted to “light mode” or “dark mode”?

I was discussing with a colleague about using dark-mode vs. light mode and remembered an article arguing that humans vision is more adapted to light-mode rather than dark-mode: I know that the trend “...
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1answer
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Is chromatic aberration related to the spectral sensitivity of the human eye and can it cause “relative myopia” and “relative farsightedness”?

in the text below, the authors equate chromatic aberration and the spectral sensitivity of the human eye. Aren't these two very different phenomena though? They also propose a so-called "relative ...
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Why do the “most sensitive photoreceptors” of insects consume so much energy it exerts evolutionary pressure to minimize receptor number?

The video Wireless Steerable Vision for Live Insects and Insect-scale Robots from the University of Washington's Paul G. Allen School of Computer Science begins with the following: Vision is an ...
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2answers
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Are 2 eyes necessary for 3D vision?

To start off: I'm not a biology student, but a computer science major It has always been my understanding that humans have 2 eyes so that we can have 3D vision: the left eye see more of the left side ...
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Which animals can see (or feel) the Moon’s infrared radiation?

The luminosity (bolometric) of the Moon in infrared is several times greater that its luminosity in visible light. Moreover, it may be rather possible for the Moon to be obscured by some fog or haze ...
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Eye Optics/Emmert's law: Where to place scaled copies of an object so they have identical images on the retina?

I read that the center of projection of the human eye is the entrance pupil. So given a light ray which intersects the objects position and the center of the aperture stop, all copies of said object ...
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1answer
5k 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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1answer
909 views

What would happen if you “rewired” your eyes with your nose?

The nose sends sensory input through transduction of chemicals in the air via the olfactory nerves/tracts to the primary olfactory cortex. The eyes send sensory input through transduction of light via ...
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1answer
74 views

How do big cats perceive objects, specifically vehicles?

Right so we have been on safari in South Africa recently and before encountering big cats (lions) we have been told to hold still and not reach out beyond the boundaries of our safari vehicle because ...
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Understanding David Chalmers claims on direct mappings between our vision and visual awareness systems

I am reading the popular 1995 paper "Facing Up to the Problem of Consciousness" by David Chalmers [PDF] as part of my philosophy course. I am only asking about the relevant vision related ...
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768 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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Why do I see different hues of colors between each of my eyes?

Frequently, I see colors with a slightly different hue when looking through my eyes individually. The right eye is more red-tinted ('warmer' hued) and the left is typically more blue-tinted ('cooler' ...
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1answer
27 views

Term for a prey animal's recognition that something potentially threatening is looking at it?

On my daily walks I frequently see individual or small groups of cattle egrets. At first I would try to photograph them but they would fly away. This vexed me because they ignored everyone else ...
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1answer
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How much percent of image does our eyes focus at any instant?

I learned in highschool that even thought we have a wide view, we only observe a tiny fraction of that view through our eyes. So at any instant we are not really looking at all the objects infront of ...
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Why is human vision restricted to 400-700 nm?

Across the electromagnetic spectrum, 400-700 nm is a narrow spectrum of frequencies and focused in the region of short wavelengths. For example, radio waves cover a large range of frequencies ...
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1answer
61 views

Why does our visible range not include infrared or UV radiation? [duplicate]

As the radiation peak of the sun is in the UV region and since at around room temperature materials emit radiation at IR, I wonder why our eyes are not capable of using these wavelengths. I guess ...
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69 views

Why do we get tunnel vision during fight or flight response?

I have a question regarding tunnel vision during the fight or flight response. I believe that during fight or flight high levels of adrenaline are released which causes the pupils to dilate allowing ...
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Why do we have both on and off bipolar cells?

I have a question regarding the reason behind the 2 bipolar cells. So, from my understanding we have both on and off bipolar cells and from the numerous diagrams I have seen, I find that most show a ...
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21 views

Why does Cyan appear bluish rather than greenish, when the phototopic eye sensitivity is highest in green (and Cyan contains blue and green equally)?

Cyan contains blue and green equally. Phototopic eye sensitivity is highest in green. Why, then, does Cyan appear bluish to most of us, rather than greenish?
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Why is 450 nm monochromatic light perceived as blue or violet depending on its intensity?

Trying to do some color matching I purchased a 450 nm laser. I expected monochromatic light of this laser to have similar properties to those of all others I've already played with — 808, 640, 520, ...
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1answer
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Why are eyes more sensitive to flicker in periphery — contradictory answers

In terms of the perception of flickering by CRT monitors, This answer suggests that peripheral vision has faster response and is thus more sensitive to flicker due to being provided by rod cells. ...
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1answer
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What is the smallest visual unit perceptible to the human eye, like a pixel? (esp. in visual static)

If you close your eyes, you can often see visual static, where individual pixel-like things are much more visible than with the more smooth, crisp images one gets with open eyes. This led me to wonder ...
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How does the human eye generate spikes?

Disclaimer: I have an academic background in computer vision but not biological vision. Background: Classical computer vision is concerned with images from cameras that have a fixed exposure time for ...
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1answer
39 views

Visual receptive fields

What I know about centre-surround type receptive fields is that depending on whether the region is on or off, the response to being stimulated is either excitatory or inhibitory respectively. So if a ...
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2answers
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Is Brain Eye connections reversed in all animals or just Humans?

I know that Brain Eye connections are reversed in Humans, Left Hemisphere controls the Right eye/Right side of the body Right Hemisphere Controls the Left eye/Left side of the body Is it true in ...
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1answer
105 views

Vitamin A Deficiency

I have a quick question regarding Vitamin A deficiency. The photoreceptor molecules in both rods and cones have the same general structure which is retinal which is bound to a protein called opsin ...
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1answer
245 views

Multiple numbers in the Ishihara test?

When I was in high school (30 years ago), I took a biology class, and the instructor showed us an Ishihara color test for color-blindness. (This is the "hidden numbers" test.) What I thought I saw ...
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1answer
145 views

Why did we lose our fourth type of cone cell (in the eye)?

Most species of birds, reptiles and fish have four types of cone cells in their retina, thus they have four independent channels for conveying color information. They are: short-wave (S) cones: ...
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1answer
961 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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Do L cone cells have a secondary peak?

I found some pictures on the internet suggesting that L cone cells (an in some M type too) have a secondary peak in the blue part of the spectrum. Is that so? Why would that be? (As if there is not ...
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3answers
1k views

Advantage of opponent color?

Opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner (source). What is ...
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1answer
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Does opponent process happen in the retina or in the brain?

I understand that both the Trichromatic Process and the Opponent Process take place in human vision. Trichromatic Process is widely accepted to happen in the retina, however I heard differing accounts ...
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2answers
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Do octopuses have better eyes than humans?

I've read that unlike humans, octopuses have eyes "designed" the "right way", i.e. with the nerve fibers behind the retina, thus getting rid of the blind spot we humans have as well as theoretically ...
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58 views

Does the human eye see things at twice the distance in a mirror?

If I'm standing 3ft away from a mirror and looking at something in it that is behind me but 5ft away from the mirror, do my eyes see that object as 3ft? Or 8?
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1answer
132 views

How are the images of both eyes combined to form one image?

When you see an object by one eye, ex.right eye, you see it from the right direction and the opposite if you see it by your left eye, but when you open both eyes, the image appears somehow centric in ...
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1answer
2k views

Can a color-blind person see color with filter glasses?

Why does color vision improve in color-blind persons using these filter glasses from Enchroma? Will a color blind person be able to see the same colors on a television? I'm asking, because the colors ...
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1answer
55 views

Vision: what is the difference between on-off ganglion cells and lateral inhibition?

Is 'lateral inhibition' just a term for the biological basis of the functioning of the on-center (or off-center) ganglion cells? Or do these terms describe separate processes?
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151 views

Is it possible to simulate tetrachromatic vision in a trichromat?

Suppose we are able to stimulate the whole matrix of cones of a human retina, targeting each cone individually¹. Normally we would project an image in the LMS color space onto the cones, in such a way ...
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Predatory animal tracking methods

As far as I know, humans are the only animals that use visual references to track prey that is not immediately visible to them. Do any other animals do this? I'm not referring to stalking prey ...
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7answers
53k views

Does red light preserve your night vision?

A number of companies have started marketing LED lamps that can be switched to a red mode. The claim is that red light is less harmful to one's night vision. Given that our eyes are less sensitive to ...
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2answers
8k views

Is it possible that by mutation a human could see infrared or other 'colours'?

Incoming light reacts with the several types of cone cells in the eye. In humans, there are three types of cones sensitive to three different spectra, resulting in trichromatic color vision. Each ...
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2answers
770 views

How far can a human see at night?

I am not talking about seeing in total darkness, which I understand is not possible. I am looking more about a question how far can a human see during starry night or with half moon/full moon. I tried ...
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Do pale skinned people show other low light adaptations?

So, pale skin is, fundamentally, an adaptation to living in low light conditions. Pros: reduce energy spent on producing melanin, increase vitamin D production. Cons: more vulnerable to sunburns and ...
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Farsightedness and the eye

When a farsighted person looks at a distant object and sees it clearly, what is the state of their eye lens? Is it relaxed? Rationale: It is something we read about in class that is confusing.I know ...
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1answer
61 views

Comparion between machine vision & human vision

I hope this is the correct Stackexchange to ask this question. I am trying to know : What is the current status of knowledge regarding human vision and pattern recognition. More specifically, How ...
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1answer
238 views

Can any organisms see non-electromagnetic radiation?

Some examples would be cosmic rays, neutron radiation, alpha radiation, beta radiation, muon radiation, and antimatter radiation. Some related questions: How is non-electromagnetic radiation detected,...
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2answers
199 views

Understanding the “Waterfall Illusion”

Motion after-effect illusions, such as the waterfall illusion, refer to illusions where fixating a screen which shows stimuli moving in a particular direction elicits the perception of motion in the ...
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596 views

Would a VR headset exacerbate myopia or could it be used to retrain the eyes?

I've learned that there are two primary hypotheses to explain myopia: not enough use of distance vision or not enough sunlight If the distance between an eye and what it's focusing on is the primary ...
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Is there benefit of use of red light over dim white light when interacting with rodents in the dark phase?

I've come across some "percieved wisdom" that rats and mice do not "see" red visible light and so use of this wavelength will allow humans to interact with rats in their active nocturnal phase without ...

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