How many PIXELS is the Human Eyeball?

Carl Merritt · March 11th, 2005, 10:31 AM

But a human eye is not videotape. We're talking about the perception of actual light energy, which I think is essentially an infinite resolution spectrum.
Though I suppose one could define light by photons and show where there is actually a "digital" aspect to light energy.

My only point was that you will never be able to perceive more than your own eye, so for all intents and purposes it's infinite, imho.

Graeme Nattress · March 11th, 2005, 10:36 AM

Well, you can set up test cards, and keep moving them nearer until you can see the pixels so to speak, on the test card. Then you can use trigonometry to calculate the angles and distances and work to figure out the size of the eye's pixels.

Or as I say, you can get a microscope and count them - they're small, but not so small as to be invisible.

There's a world of difference between a large, finite number and an infinite number.

Just because you cannot percieve more than the limits of your own perception does not make your perception infinite.

Graeme

Christopher C. Murphy · March 11th, 2005, 11:07 AM

We're forgetting that no two moments of visual images captured by our brain are the same! Even in complete darkness we actually "see" too.

In addition, we have two eyes and each one is unique on how it translate light into images in our brain. It's very interesting!

Carl Merritt · March 11th, 2005, 11:32 AM

<<<-- Originally posted by Graeme Nattress :
There's a world of difference between a large, finite number and an infinite number.

Just because you cannot percieve more than the limits of your own perception does not make your perception infinite.

Graeme -->>>

But if you cannot perceive the difference, is there a difference? :)

I understand the point that there is a limit to detail perception for each person.

I have not seen an 8K image projected, but I can imagine it would be perceptibly similar to 35mm for most people. Surely 35k imagery would be above and beyond requriements.

Christopher C. Murphy · March 11th, 2005, 11:50 AM

Online about a year ago somewhere I read this article about the Japanese...they created a super-HD camera. It was like 8k or something and they took it out and shot on the street while driving. They weaved through traffic and tried to give a real life like ride.

They projected it for people sitting in chairs in a room and they all started barfing! Apparently, the "motion" made them sick because their bodies weren't moving. That's going to be some really cool stuff when they figure out how to get it all together.

Steven White · March 11th, 2005, 12:30 PM

>>We're talking about the perception of actual light energy, which I think is essentially an infinite resolution spectrum. <<

GAH!!!! What the heck is a "resolution spectrum"?

As I've heard thus far (you never, know the profs could still be lying to me) space is NOT quantized... However, the quantum nature of light dictates the ultimate resolution of the visible spectrum. The resolution of light is limited by its wavelength/energy (related by Plank's constant), with visible light on the order of 100's of nm, and hence light can't accurately be used to resolve structures much smaller than 0.1 μm without incurring significant undersampling artifacts (otherwise known as diffraction).

I have no respect for the whole "if I can't see it, it doesn't matter" approach. We build cameras to be better than our eyes, so that our intrinsic frame of reference is not the limiting case in our perception of what's happened.

Joe Carney · March 11th, 2005, 01:20 PM

Think abot those spy cameras that can read license plates at 60k feet. Much better than the human eye.

Carl Merritt · March 11th, 2005, 02:05 PM

<<<-- Originally posted by Steven White :
GAH!!!! What the heck is a "resolution spectrum"?-->>>

Answer:

<<<-- Originally posted by Steven White :
However, the quantum nature of light dictates the ultimate resolution of the visible spectrum.-->>>

So you're saying it's not infinite - fine with me.

<<<-- Originally posted by Steven White :
I have no respect for the whole "if I can't see it, it doesn't matter" approach. We build cameras to be better than our eyes, so that our intrinsic frame of reference is not the limiting case in our perception of what's happened. -->>>

But your visual perception is the limit of your visual frame of reference. If you had the ability to capture and display xrays, sure your camera is doing more than an eye is capable of perceiving, but you'd never know - unless you measured the xrays coming off of your screen.

But you wouldn't see them.

Plus, isn't the whole point of this thread to guess at what is the limit of perception?
The question being how much resolution is required to match what one can perceive?

If people literally cannot perceive more than 35k resolution image, what would be the point of making it 36k?

I would say, if one cannot perceive more than 35k, then it doesn't matter if the image is 36k.

Carl Merritt · March 11th, 2005, 02:18 PM

<<<-- Originally posted by Joe Carney : Think abot those spy cameras that can read license plates at 60k feet. Much better than the human eye. -->>>

But that's the lens is it not?

If you could put your eye on the end of that lens, I bet you could read the license plate too - or am i thinking of the wrong thing?

Steven White · March 11th, 2005, 02:32 PM

>>I would say, if one cannot perceive more than 35k, then it doesn't matter if the image is 36k.<<

My argument is the following:

If I had a camera that could capture x-rays, I could translate that information into something my eye COULD see. That is in fact the whole point of medical x-rays, which are surely useful. My point is that while your eyes are limited, capturing information you can't perceive is possible. It is further possible to translate those into things you can perceive.

>>If people literally cannot perceive more than 35k resolution image, what would be the point of making it 36k?<<

The answer is that people cannot perceive a 35k image instantly... however, given enough time on a single image, we COULD process all the information. If we took a 36k image, eventually we could process that too. This is the point of something like the gigapixel project.

The point of increasing resolution is to add "depth" to the experience. The world around us is significantly more detailed than we can perceive, and I think we find comfort in knowing that if we looked harder, we could find out more. This is what's so great about IMAX and other large-format images... or photography in general.

I hold that one of the reasons people find CG frustrating is that they can tell there's nothing more there than what they've been shown. If they go closer, you'll see detours from reality and engineering hacks to the render... and once you've cracked that, there's no where left to go. Litterally an empty shell.

It all comes down to philosophy I guess.

Carl Merritt · March 11th, 2005, 03:25 PM

Yes, it is very interesting. :)

Peter Moore · March 11th, 2005, 03:53 PM

I remember reading once, and I wish I knew the source, that a person with 20/20 can resolve approximately 1/60th of one degree of resolution. At 10 feet away, this would be 35/1000ths of an inch.

Now, we're told that the ideal picture size is 1/2 the viewing distance, right? The diagonal would be 60 inches, the horizontal would be 52" and the vertical would be 29".

So ideal viewing distance, and ideal 16x9 screen size. Let's make the pixels exactly as small as the human eye can see and no smaller.

52" / .0035" = 1490
29" / .0035" = 831

There you have it. A TV screen at ideal viewing distance needs to have 1490x831 resolution for the pixels to be invisible to the eye. As it happens, HDTV is 1920 x 1080 or 1280 x 720. So 720p and 1080i are slightly under what the eye would consider seamless, while 1080p is more than enough.

If we go the other way, and say how far should we sit from a certain TV set in order to have a seamless picture, that's easy.

For a screen width of 1920 pixels, take the screen width in inches, w. Pixel_size = w / 1920. tan(1/60 degrees) = pixel_size / viewing_distance. viewing_distance = pixel_size / .000291.

viewing_distance = (w / 1920) / .000291

viewing_distance = w / .56 = 1.8w

So for a 1080p display, multiply your screen width by 1.8 to get your ideal viewing distance.

For 720p, it's:

distance = w / (1280 * .000291)

viewing_distance = 2.7w

QED.

Colin Wyers · March 11th, 2005, 04:39 PM

The thing is, the eye doesn't resolve images along a plane, the way either film or digital does. There aren't actually "pixels" in a 3D image.

Carl Merritt · March 11th, 2005, 09:27 PM

@Peter Moore

So you'd need a 60" 1080p HD display 5' away to enjoy a perfect viewing experience!?
IT'D BE LIKE IMAX!!
lol!

Anhar Miah · March 18th, 2005, 07:41 PM

oh guys you are talking about my fav subject, i'd written about this here @ Dvinfo way back, and also at extreme in depth @ dvxuser.com about the exact Long long chemical reactions ...

Anyway that aside i Just couldnt resist to ask the age old question:

"To whom does the eye inside belong?"

please visit this excellent site for more info about this topic
(read all the pages, you will love it!)

http://www.secretbeyondmatter.com/ou...ourbrains.html

March 11th, 2005, 10:36 AM	#17
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	Well, you can set up test cards, and keep moving them nearer until you can see the pixels so to speak, on the test card. Then you can use trigonometry to calculate the angles and distances and work to figure out the size of the eye's pixels. Or as I say, you can get a microscope and count them - they're small, but not so small as to be invisible. There's a world of difference between a large, finite number and an infinite number. Just because you cannot percieve more than the limits of your own perception does not make your perception infinite. Graeme __________________ www.nattress.com - filters for FCP

March 11th, 2005, 11:07 AM	#18
Christopher C. Murphy Trustee Join Date: Sep 2003 Location: Boston, MA Posts: 1,707	We're forgetting that no two moments of visual images captured by our brain are the same! Even in complete darkness we actually "see" too. In addition, we have two eyes and each one is unique on how it translate light into images in our brain. It's very interesting! __________________ Christopher C. Murphy Director, Producer, Writer

March 11th, 2005, 11:50 AM	#20
Christopher C. Murphy Trustee Join Date: Sep 2003 Location: Boston, MA Posts: 1,707	Online about a year ago somewhere I read this article about the Japanese...they created a super-HD camera. It was like 8k or something and they took it out and shot on the street while driving. They weaved through traffic and tried to give a real life like ride. They projected it for people sitting in chairs in a room and they all started barfing! Apparently, the "motion" made them sick because their bodies weren't moving. That's going to be some really cool stuff when they figure out how to get it all together. __________________ Christopher C. Murphy Director, Producer, Writer

March 18th, 2005, 07:41 PM	#30
Anhar Miah Major Player Join Date: Dec 2003 Location: United Kindom, England Posts: 290	Philosophical debate oh guys you are talking about my fav subject, i'd written about this here @ Dvinfo way back, and also at extreme in depth @ dvxuser.com about the exact Long long chemical reactions ... Anyway that aside i Just couldnt resist to ask the age old question: "To whom does the eye inside belong?" please visit this excellent site for more info about this topic (read all the pages, you will love it!) http://www.secretbeyondmatter.com/ou...ourbrains.html

March 11th, 2005, 10:31 AM	#16
Carl Merritt Regular Crew Join Date: Apr 2004 Posts: 60	But a human eye is not videotape. We're talking about the perception of actual light energy, which I think is essentially an infinite resolution spectrum. Though I suppose one could define light by photons and show where there is actually a "digital" aspect to light energy. My only point was that you will never be able to perceive more than your own eye, so for all intents and purposes it's infinite, imho.

March 11th, 2005, 11:32 AM	#19
Carl Merritt Regular Crew Join Date: Apr 2004 Posts: 60	<<<-- Originally posted by Graeme Nattress : There's a world of difference between a large, finite number and an infinite number. Just because you cannot percieve more than the limits of your own perception does not make your perception infinite. Graeme -->>> But if you cannot perceive the difference, is there a difference? :) I understand the point that there is a limit to detail perception for each person. I have not seen an 8K image projected, but I can imagine it would be perceptibly similar to 35mm for most people. Surely 35k imagery would be above and beyond requriements.

March 11th, 2005, 12:30 PM	#21
Steven White Major Player Join Date: Nov 2004 Location: Canada Posts: 547	>>We're talking about the perception of actual light energy, which I think is essentially an infinite resolution spectrum. << GAH!!!! What the heck is a "resolution spectrum"? As I've heard thus far (you never, know the profs could still be lying to me) space is NOT quantized... However, the quantum nature of light dictates the ultimate resolution of the visible spectrum. The resolution of light is limited by its wavelength/energy (related by Plank's constant), with visible light on the order of 100's of nm, and hence light can't accurately be used to resolve structures much smaller than 0.1 μm without incurring significant undersampling artifacts (otherwise known as diffraction). I have no respect for the whole "if I can't see it, it doesn't matter" approach. We build cameras to be better than our eyes, so that our intrinsic frame of reference is not the limiting case in our perception of what's happened.

March 11th, 2005, 01:20 PM	#22
Joe Carney Inner Circle Join Date: Jul 2002 Location: Centreville Va Posts: 1,828	Think abot those spy cameras that can read license plates at 60k feet. Much better than the human eye.

March 11th, 2005, 02:05 PM	#23
Carl Merritt Regular Crew Join Date: Apr 2004 Posts: 60	<<<-- Originally posted by Steven White : GAH!!!! What the heck is a "resolution spectrum"?-->>> Answer: <<<-- Originally posted by Steven White : However, the quantum nature of light dictates the ultimate resolution of the visible spectrum.-->>> So you're saying it's not infinite - fine with me. <<<-- Originally posted by Steven White : I have no respect for the whole "if I can't see it, it doesn't matter" approach. We build cameras to be better than our eyes, so that our intrinsic frame of reference is not the limiting case in our perception of what's happened. -->>> But your visual perception is the limit of your visual frame of reference. If you had the ability to capture and display xrays, sure your camera is doing more than an eye is capable of perceiving, but you'd never know - unless you measured the xrays coming off of your screen. But you wouldn't see them. Plus, isn't the whole point of this thread to guess at what is the limit of perception? The question being how much resolution is required to match what one can perceive? If people literally cannot perceive more than 35k resolution image, what would be the point of making it 36k? I would say, if one cannot perceive more than 35k, then it doesn't matter if the image is 36k.

March 11th, 2005, 02:18 PM	#24
Carl Merritt Regular Crew Join Date: Apr 2004 Posts: 60	<<<-- Originally posted by Joe Carney : Think abot those spy cameras that can read license plates at 60k feet. Much better than the human eye. -->>> But that's the lens is it not? If you could put your eye on the end of that lens, I bet you could read the license plate too - or am i thinking of the wrong thing?

March 11th, 2005, 02:32 PM	#25
Steven White Major Player Join Date: Nov 2004 Location: Canada Posts: 547	>>I would say, if one cannot perceive more than 35k, then it doesn't matter if the image is 36k.<< My argument is the following: If I had a camera that could capture x-rays, I could translate that information into something my eye COULD see. That is in fact the whole point of medical x-rays, which are surely useful. My point is that while your eyes are limited, capturing information you can't perceive is possible. It is further possible to translate those into things you can perceive. >>If people literally cannot perceive more than 35k resolution image, what would be the point of making it 36k?<< The answer is that people cannot perceive a 35k image instantly... however, given enough time on a single image, we COULD process all the information. If we took a 36k image, eventually we could process that too. This is the point of something like the gigapixel project. The point of increasing resolution is to add "depth" to the experience. The world around us is significantly more detailed than we can perceive, and I think we find comfort in knowing that if we looked harder, we could find out more. This is what's so great about IMAX and other large-format images... or photography in general. I hold that one of the reasons people find CG frustrating is that they can tell there's nothing more there than what they've been shown. If they go closer, you'll see detours from reality and engineering hacks to the render... and once you've cracked that, there's no where left to go. Litterally an empty shell. It all comes down to philosophy I guess.

March 11th, 2005, 03:25 PM	#26
Carl Merritt Regular Crew Join Date: Apr 2004 Posts: 60	Yes, it is very interesting. :)

March 11th, 2005, 03:53 PM	#27
Peter Moore Trustee Join Date: Oct 2002 Location: Arlington VA Posts: 1,034	I remember reading once, and I wish I knew the source, that a person with 20/20 can resolve approximately 1/60th of one degree of resolution. At 10 feet away, this would be 35/1000ths of an inch. Now, we're told that the ideal picture size is 1/2 the viewing distance, right? The diagonal would be 60 inches, the horizontal would be 52" and the vertical would be 29". So ideal viewing distance, and ideal 16x9 screen size. Let's make the pixels exactly as small as the human eye can see and no smaller. 52" / .0035" = 1490 29" / .0035" = 831 There you have it. A TV screen at ideal viewing distance needs to have 1490x831 resolution for the pixels to be invisible to the eye. As it happens, HDTV is 1920 x 1080 or 1280 x 720. So 720p and 1080i are slightly under what the eye would consider seamless, while 1080p is more than enough. If we go the other way, and say how far should we sit from a certain TV set in order to have a seamless picture, that's easy. For a screen width of 1920 pixels, take the screen width in inches, w. Pixel_size = w / 1920. tan(1/60 degrees) = pixel_size / viewing_distance. viewing_distance = pixel_size / .000291. viewing_distance = (w / 1920) / .000291 viewing_distance = w / .56 = 1.8w So for a 1080p display, multiply your screen width by 1.8 to get your ideal viewing distance. For 720p, it's: distance = w / (1280 * .000291) viewing_distance = 2.7w QED.

March 11th, 2005, 04:39 PM	#28
Colin Wyers New Boot Join Date: Feb 2005 Location: Davenport, IA Posts: 13	The thing is, the eye doesn't resolve images along a plane, the way either film or digital does. There aren't actually "pixels" in a 3D image.

March 11th, 2005, 09:27 PM	#29
Carl Merritt Regular Crew Join Date: Apr 2004 Posts: 60	@Peter Moore So you'd need a 60" 1080p HD display 5' away to enjoy a perfect viewing experience!? IT'D BE LIKE IMAX!! lol!