What Is The Resolution Of The Eye?

Summary

In this video, Michael from Vsauce explores the comparison between human vision and camera resolution. He explains that while cameras capture static images, human sight is a dynamic process, involving the brain's constant processing of data from the eyes. Although our eyes can differentiate fine details, human vision isn't as digital as pixels. Michael also discusses the limits of human vision, using the example of foveal resolution and blind spots. He concludes with a philosophical reflection on how life doesn't follow the structured narrative of movies, emphasizing life's continuous, unresolved nature.

Takeaways

• 🎥 Hollywood doesn't produce the most films annually—India does, followed by Nigeria.
• 👀 The human eye's resolution isn't comparable to a camera; it uses a complex process to perceive the world.
• 🧠 Our brain processes the information from our eyes, often filling in gaps like blind spots and filtering out unimportant details.
• 🎨 The fovea, which only covers 2 degrees of your field of view, provides optimal vision, with the rest being lower in resolution.
• 📸 Roger N. Clark estimated that the human eye can resolve up to 576 megapixels, but only around 7 megapixels are needed for the fovea's sharp focus.
• 🖼️ Human vision isn't digital, and perception isn't stored as a perfect snapshot like a digital camera file.
• 📺 Technologies like Retina Displays can already fool our eyes, showing that certain pixel densities are beyond what we can differentiate.
• 🎞️ Real life isn't like a movie; conflicts don't have neatly resolved endings, and life is continuous without a narrative resolution.
• 📐 Our visual system is more about continuous perception and top-down processing than discrete pixel resolution.
• 🔄 Life moves on after events in ways that movies can't portray, showing the difference between cinematic and real-life experiences.

Q & A

What countries produce the most feature films annually?

India produces the most feature films annually, followed by Nigeria. Hollywood in the United States, though famous, does not produce the most.

How does human eye resolution compare to camera or screen resolutions?

The human eye doesn't function like a camera. While camera resolutions are measured in pixels, the eye processes information differently, combining signals from various parts of the field of view. An estimate suggests the human eye has a resolution of about 576 megapixels, but this analogy is crude.

What is spatial resolution, and how does it affect how we see details?

Spatial resolution refers to the ability to distinguish between nearby pixels or fine details. The more distinct adjacent pixels are, the more details can be resolved. Factors like lighting, sensor size, and how close the subject is all affect resolution.

Why do we not see our noses or glasses in our field of vision?

The brain filters out unchanging stimuli, such as our noses or glasses, because they are not important for processing new visual information.

What is the role of the fovea in vision?

The fovea is a small pit in the retina that handles central vision, providing optimal color vision and 20/20 acuity. It only covers about two degrees of our field of view.

How does the brain process blind spots in our vision?

The brain fills in details and merges information from both eyes, compensating for the blind spots caused by where the optic nerve connects to the retina.

How many megapixels would be required to display an image indistinguishable from reality?

If we consider the entire field of view, around 576 megapixels would be needed to create an image that the average human eye can't differentiate from reality. However, for the central vision processed by the fovea, only about 7 megapixels are required.

Why doesn't human vision work like a digital camera?

Unlike a camera that captures static frames, our eyes constantly move, and the brain merges all the visual inputs into a processed perception. The resulting image is not made of pixels but is a dynamic, top-down interpretation of our surroundings.

Can humans have photographic memory?

No scientific evidence supports the existence of photographic memory. Human memory is not stored with the same accuracy as a digital camera file.

What is the difference between life and movies in terms of narrative resolution?

Unlike movies that often have clear beginnings, conflicts, and resolutions, life is continuous and doesn't resolve in neat, discrete ways. Life keeps going even after key moments pass.

Outlines

00:00

🎥 Human Vision vs. Camera Resolution: A Deep Dive

Michael from Vsauce begins by discussing the filmmaking industry, comparing production in Hollywood, Nigeria, and India. He transitions to examining how the human eye's resolution compares to that of cameras and screens, referencing formats like VHS, DVD, and IMAX. He explores the idea that pixel dimensions alone don't define resolution, emphasizing other factors like light, sensor size, and proximity. Using Salvador Dali's optical illusions and spatial resolution as examples, he explains how the human eye perceives and processes visual details differently from cameras. Michael raises the question of how many pixels would be needed for a screen to match human vision without noticeable pixelation, though he notes the complexity due to the brain’s processing of sight, which differs from the static frame capture of a camera.

05:04

👁️ The Human Eye's Pixel Power and Visual Processing

Michael continues his investigation into the resolution of human vision. He references Roger N. Clark’s estimate that the human eye can distinguish up to 576 megapixels when considering the full field of view. However, he clarifies that this number assumes perfect acuity across the entire visual field, which is unrealistic due to the fovea—a small part of the retina responsible for sharp central vision. During a single glance, the fovea processes only about 7 megapixels worth of information, with the peripheral vision needing just 1 additional megapixel. He highlights how modern technologies like Retina Displays already surpass the pixel density the human eye can distinguish at common viewing distances. Ultimately, Michael underscores that human vision is far more fluid and dynamic than digital resolution, as the brain processes visual input in a continuous, adaptive manner rather than capturing it in a pixel-based format.

Keywords

💡Resolution

Resolution in this context refers to the ability to distinguish fine details in an image. In the video, resolution is discussed in terms of both digital screens and human vision. It emphasizes that while pixel dimensions are important, resolution also depends on factors like light, sensor size, and proximity. The comparison highlights that the human eye processes images differently from a camera.

💡Fovea

The fovea is a small pit on the retina that is responsible for sharp central vision. It covers only about two degrees of the field of view, where optimal color vision and acuity are possible. In the video, the fovea's role is crucial in explaining why humans don't perceive the entire visual field with the same clarity.

💡Megapixels

Megapixels represent a measure of resolution, indicating how many millions of pixels an image contains. The video uses this term to compare digital camera resolution to human vision, suggesting that the human eye can resolve about 576 megapixels across its entire field of view, although this figure is much lower when considering the fovea’s central area.

💡Blind spots

Blind spots are areas in the human visual field where no image is perceived because the optic nerve meets the retina, and no visual information is received. The video highlights that unlike cameras, human vision has these blind spots, but our brain compensates by filling in the gaps, creating a seamless image.

💡Spatial resolution

Spatial resolution refers to the ability to distinguish between different objects or points that are close together. The video explains how, even if the number of pixels remains constant, details can become indistinguishable if an image is out of focus, emphasizing that spatial resolution is more complex than just pixel count.

💡Neon color spreading illusion

This illusion demonstrates how human perception can be tricked, showing that what we see is not always based on objective reality. The video uses this illusion to show how our brain processes visual stimuli and how the perception of color and shapes can be altered, unlike a camera, which captures images without such subjective adjustments.

💡Cinematic resolution

Cinematic resolution is a metaphor used to contrast how life and movies handle the progression of events. The video suggests that while movies have neatly resolved narratives with clear beginnings and endings, real life is continuous and unresolved, lacking the clear-cut resolution often seen in films.

💡Photographic memory

Photographic memory is the hypothetical ability to remember images in perfect detail, like a camera. The video states that no evidence exists for such a memory in humans, emphasizing that human memory and vision are processed and imperfect, unlike digital storage in cameras.

💡Field of view

Field of view refers to the extent of the observable world seen at any given moment. In the video, the field of view is used to calculate how many pixels human vision can appreciate, with Roger N. Clark estimating that 576 megapixels would be required to match human vision across the entire field of view.

💡Top-down processing

Top-down processing refers to how the brain interprets sensory information based on prior knowledge, expectations, and experiences. The video explains that human vision involves this type of processing, where the brain creates a final perception from incomplete or imperfect visual input, rather than simply recording reality like a camera.

Highlights

Michael introduces the location—The White House in Washington, D.C.

Discussion of global film industries, revealing India as the largest producer of feature films annually.

Insight into the differences between camera resolution and the resolution of the human eye.

Explanation of how pixel count alone doesn’t determine image quality—other factors like light and sensor size are crucial.

Demonstration of how resolution depends on spatial resolution—how different nearby pixels are from each other.

Introduction of the fovea, a small part of the retina responsible for high-detail vision.

Explanation of blind spots in human vision due to the optic nerve and how the brain compensates for them.

Clarification that the human eye does not function like a camera, as vision is a brain-generated, processed experience.

Roger N. Clark’s calculation that human vision can resolve up to 576 megapixels across a full field of view.

Only 7 megapixels are needed in the central two degrees of vision for optimal acuity, with about 1 megapixel for peripheral vision.

Reference to modern technologies like Apple’s Retina Displays, which already exceed human visual resolution.

Explanation of how human memory is not photographic and that no evidence exists for the existence of a truly photographic memory.

Contrast between cinematic narratives, which have clear beginnings and endings, and real-life, which is continuous and unresolved.

Comparison between the resolution of film narratives and the 'ear resolution' of real life, which lacks clear, cinematic closure.

Final philosophical reflection on how life doesn’t have a distinct end, but only a continuation—'the and.'

Transcripts

Hey, Vsauce. Michael here.

I am at the White House, in America's capital,

Washington, D.C. America makes a lot of feature films every year -

Hollywood. But they don't make the most feature films every year. Nigeria makes more.

But the country that makes the most films every single year is

India. Every two years, the country

of India fills up enough film with unique feature films

that stretch all the way from this city, Mumbai, to where I live,

in London. That's double what Hollywood produces in two years.

That is a lot of movies, but is

real-life a movie? I've discussed the frame rate of the human eye before but how

does the resolution

of the human eye compare to a camera or screen?

VHS, LaserDisc, DVD,

Blu-ray, IMAX. Numbers like these are pixel dimensions. When multiplied

they tell us the total number of picture elements an image is made up of.

A figure often used to describe digital cameras. It might sound like

more is better, but to be sure numbers like 1920 by 1080

are not resolutions per se. More pixels is only part

of the equation. Resolution is about distinguishing

fine details and that depends on a lot of other factors.

For instance, the amount of light, the size of the sensors,

what the millions of pixels are actually encoding and

how close the subject is. I mean, up close

Salvador Dali's painting of his wife looking at the Mediterranean can be

resolved into boxes. But from a far,

well, it's Abraham Lincoln. For crying out loud, on a small enough screen

from far enough away, low and high, so-called resolutions on screens, aren't

even resolved differently

from one another by your eye.

How different nearby pixels are from one another also matters. This is called

spatial resolution.

For instance, if I go out-of-focus

the number of pixels in the video frame stays the same but you can't resolve as much

detail. Now, with all this in mind we can still

compare human vision to a digital image, by asking a better question.

Assuming everything else is optimal, how many pixels would you need to make an

image on a screen large enough to fill your entire field of view

look like real life, without any detectable

pixelation? Now we are getting somewhere.

Kind of. The analogy is still crudy

because a camera snaps an entire frame at once, whereas

our eyes move around. The brain amalgamates

their constant stream of information into what we call vision -

sight. In fact, the image created by the eyeball alone during a single glance

would hardly even be acceptable on a broken TV screen. We think

our eyes create images like this picture Guy took of me with a camera.

But for one thing, unlike a camera, you've got some stuff

in the way. For instance, you are always

looking at your own nose, and maybe even glasses,

if you have them. Luckily, our brains process those stimuli out because they

don't matter

and they don't change. But thinking those are the only difference

is a pitfall, literally,

latinly. The fovea gets its name from the Latin for

'pitfall'. The fovea is the pit on your retina that receives light from the

central two degrees

of your field of view, about the area covered by both your thumbs

when held at arms length away. Optimal colour vision and 20/20 acuity are

only possible within that little area. When it comes to these limitations XKCD[.com]

has a brilliant illustration.

It points out other problems, like blind spots - literal blank spaces

in our vision where the optic nerve meets up with the retina

and no visual information is received. If you bought

a camera that did this, you would return it.

You can find your own blind spot by closing

your right eye, fixating your left eye on a point in front of you,

extending your left thumb and then moving it

left-of-center slightly slowly carefully until

it's not there anymore. Crazy(!) But, of course,

we don't see the world horribly, like this, because our eyes are constantly moving,

dragging foveal resolution wherever we need it.

And our brains' complex visual system fills in details,

merges images from both eyes and makes a lot of gueses. What we actually see

is a processed image. Not computer-generated imagery, but,

well, meat-generated imagery. The neon color spreading illusion

is a great way to demonstrate this difference. There is no

blue circle in this picture. The white here

is the same as the white here. A camera

isn't fooled, a screen isn't fooled, only

you and the fleeting gumbo of ingredients you call perception

is fooled. Our vision

is not analogous to a camera. But our reformulated question can still be

answered because human anatomy allows us to resolve, to differentiate certain

angular distances. Famously, Roger N .Clark

used a figure of 0.59 arcminutes as the resolution of the human eye to calculate,

based on the size of our total field of view,

how many of these distinct elements could fit inside of it.

The result was an approximation of exactly what we want to know:

how many individual picture elements - pixels - our vision can appreciate.

His answer? 576 megapixels.

That many pixels, packed inside a screen large enough to fill

your entire field of view, regardless of proximity,

would be close enough to be undetectable by the average

human eye. But we should factor in the fovea,

because Clark's calculation assumes optimal acuity everywhere, it allows the

eye to move around.

But a single glance is more analogous to a camera snap, and, as it turns out,

only about 7 megapixels, packed into the two degrees of

optimal acuity the fovea covers during a fixed stare,

are needed to be rendered undetectable. It's been roughly estimated that the

rest of your field of view would only need about

1 megapixel more information. Now that might sound low but keep in mind that there

are plenty of modern technologies that already use pixel densities

better than we can differentiate. As Bad Astronomer deftly showed,

Apple's Retina Displays truly do contain pixels at a density

average eyesight can't differentiate from typical

reading distances. But the fact that there are screen sizes and pixel

densities that can fool the human eye

is not a sign that we see in

any kind of megapixelly way. Human vision just

isn't that digital. I mean, sure, like a camera sensor we only have a finite

and discrete number of cells in our retina.

But the brain adjusts our initial sensations into a final perception

that is a wishy-washy top-down processed blob

of experience. It's not made of pixels

and furthermore, unlike a camera, it's not saved in memory with veracity like a

digital camera file.

Absolutely no evidence has ever been found for the existence of a truly

photographic memory. And what's even cooler is that not only do we not

visually resolve the real world, like a movie camera,

we also don't narratively resolve conflict and drama in our lives

like most movie scripts. The point of all of this, what I'm getting at,

is an idea. An idea that initially drew me to this question.

We play roles in the movie of life,

but it's a special kind of movie. Cinematic victories and struggles are often

discrete, resolved, like pixels, with unbelievably perfect beginnings and endings,

whereas the real world is all about ear resolution.

I like how Jack Angstreich put it in 'Cinemania'.

In a movie, a character can make a decision and then walk away from the camera

across the street and have the credits roll, freezing life in a perfect happily ever after.

But in the real world, after you cross the street,

you have to go home. The world goes on.

Life doesn't appear in any particular pixel resolution

or narrative resolution. Things are

continuous. The world was running before you came around and it will continue running

after you are gone. Your life is a plot only in so far as it begins

and ends and occurs in medias res.

Damerish opens illustration for Charles McGrath's endings

without endings says it perfectly. In life, there rarely is

the end. There is only

the and.

And as always,

thanks for watching.