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Your eyes suck at blue

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Re: Your eyes suck at blue

#21

Post by sliverstorm »

corysama wrote: post #14
bradleyland wrote: post #7

Ugh. We don't have an entirely clear picture of how our eyes physically detect color, much less how we perceive it, but there are serious problems with the argument the author makes here. You cannot simply take a color photograph of a scene, split it in to three channels, then point out that the blue channel is "dark and contains less detail" as evidence of our inability to perceive the color blue. The fact is that t…

I do know a little about human color perception. Although the author's example is flawed, his argument does stand. Human eyes are much less sensitive to details in blue compared to green and red. Here's the best illustration I can find in a minute's googling: http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWEN... from http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWEN... This shows up in the Red-vs…

> Human eyes are much less sensitive to details in blue compared to green and red

IIRC our strength with green is why many night-vision systems use only green. It has other benefits such as not killing your night vision, but when you take the darkness of the night and remove the red and blue components, you can see better. Once again, IIRC.

Re: Your eyes suck at blue

#22

Post by ajg1977 »

Trivia: DXT compression (the texture compression used in virtually all modern games) uses a 5:6:5 format for end channels giving the green channel the extra bit of precision, for exactly this reason.

Re: Your eyes suck at blue

#23

Post by jkic47 »

DrStalker wrote: post #18

Does the article mention that images taken with a digital camera (with a few exceptions) only sample 1/2 the green pixels and 1/4 each of the red and blue ones? http://en.wikipedia.org/wiki/Bayer_filter There will be more information in the green channel because that is how the camera is built. I'm sure somewhere there is proper research that was was used in developing the Bayer filter that indicates the human eye is…

To add to your point, a typical imager pixel can only sense one color - red, green or blue (caveat: there are now some imagers that can simultaneously sense multiple colours). The green value of a non-green pixel is interpolated from the surrounding pixels capable of sensing green. Thus, only 1/3 of your RGB image is "real" - the remaining 2/3 is interpolated.

Re: Your eyes suck at blue

#24

Post by mynameishere »

icegreentea wrote: post #4
olalonde wrote: post #2

I wouldn't have thought so given that blue is the favorite color of most people[1]. [1] http://www.joehallock.com/edu/COM498/preferences.html

Not really. Favourite colours have to do more with social and cultural features than your ability to finely distinguish between different shades of said colour. I strongly believe that the proper phrasing for the results should not be "blue is the favorite color of most people" but rather "blue is the favourite colour of most White North Americans/Western Europeans". I bet if this was done in China, it would be more…

I think this is why people like blue.

http://www.flickr.com/photos/lighthearted/37225804/

Re: Your eyes suck at blue

#25

Post by corysama »

sliverstorm wrote: post #21
corysama wrote: post #14

Earlier quoted context omitted.

I do know a little about human color perception. Although the author's example is flawed, his argument does stand. Human eyes are much less sensitive to details in blue compared to green and red. Here's the best illustration I can find in a minute's googling: http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWEN... from http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWEN... This shows up in the Red-vs…

> Human eyes are much less sensitive to details in blue compared to green and red IIRC our strength with green is why many night-vision systems use only green. It has other benefits such as not killing your night vision, but when you take the darkness of the night and remove the red and blue components, you can see better. Once again, IIRC.

While looking for the illustration above, I also found this page http://starizona.com/acb/ccd/advtheorycolor.aspx with this illustration of "Spectral response of the dark-adapted human eye. Note the lack of red sensitivity." http://starizona.com/acb/ccd/advimages/eyeqenight.jpg

Compared to the daylight-adapted eye: http://starizona.com/acb/ccd/advimages/eyeqe.jpg

This is interesting news to me.

Re: Your eyes suck at blue

#26

Post by jemfinch »

bradleyland wrote: post #7

Ugh. We don't have an entirely clear picture of how our eyes physically detect color, much less how we perceive it, but there are serious problems with the argument the author makes here. You cannot simply take a color photograph of a scene, split it in to three channels, then point out that the blue channel is "dark and contains less detail" as evidence of our inability to perceive the color blue. The fact is that t…

You're wrong.

No, you can't just split a picture into three channels and say "Hey, blue looks dark," because blue might actually be dark.

You can, however, make a picture grayscale, then turn that same grayscale picture into redscale, greenscale, and bluescale. The luminance would be exactly the same for every pixel, the only difference would be the pixel's color.

I did that, in fact, and you know what? Your eyes really do suck at blue: http://www.flickr.com/photos/jemfinch/sets/72157617048178001...

We do have a clear enough picture of how our eyes work to know that the blue receptors are far fewer than the red and green receptors. Your eyes suck at blue. My eyes suck at blue. All of our eyes suck at blue.

Every time this story comes up, someone brings up this point. That's why I did it right: so I could reply to arrogant comments like yours that assume because an experiment is flawed that the theory it tried to prove must be wrong.

Re: Your eyes suck at blue

#27

Post by sliverstorm »

corysama wrote: post #25
sliverstorm wrote: post #21

Earlier quoted context omitted.

> Human eyes are much less sensitive to details in blue compared to green and red IIRC our strength with green is why many night-vision systems use only green. It has other benefits such as not killing your night vision, but when you take the darkness of the night and remove the red and blue components, you can see better. Once again, IIRC.

While looking for the illustration above, I also found this page http://starizona.com/acb/ccd/advtheorycolor.aspx with this illustration of "Spectral response of the dark-adapted human eye. Note the lack of red sensitivity." http://starizona.com/acb/ccd/advimages/eyeqenight.jpg Compared to the daylight-adapted eye: http://starizona.com/acb/ccd/advimages/eyeqe.jpg This is interesting news to me.

This caught up with me once as a young teenager; I was driving home on Halloween (totally sober) and I completely didn't see a stoplight. The red just blended in with the darkness.

Re: Your eyes suck at blue

#28

Post by jemfinch »

bradleyland wrote: post #13
confuzatron wrote: post #10

Earlier quoted context omitted.

Lots of text there, and you certainly sound confident, but I tried an experiment, and it confirmed the claims of the article. I used Paint.NET, loaded in an image, copied it to three layers. Adusted each layer to be a single colour channel, then changed each of the layers to 'Additive' mode. Pixellating the blue layer - I could perceive at most some 'colour blotching', but no real loss of 'sharpness' Pixellating the…

The additive color model isn't exactly the same as the layer modes you'll see in image editing apps. This "mode" affects how the values of the current layer are applied to the layers below it. The normal mode is to replace the values below. When you switch to additive, the RGB channels from the current layer are "added" to the values of the layer below. This is entirely different than the concept of the additive colo…

> On a properly calibrated display, the display of RGB[0,255,0] and RGB[0,0,255] should have identical luminance values.

It does, and your eyes still suck at blue.

Why do you fight so vehemently against the scientific fact that your eyes have fewer blue receptors?

Re: Your eyes suck at blue

#29

Post by tensor »

jemfinch wrote: post #26
bradleyland wrote: post #7

Ugh. We don't have an entirely clear picture of how our eyes physically detect color, much less how we perceive it, but there are serious problems with the argument the author makes here. You cannot simply take a color photograph of a scene, split it in to three channels, then point out that the blue channel is "dark and contains less detail" as evidence of our inability to perceive the color blue. The fact is that t…

You're wrong. No, you can't just split a picture into three channels and say "Hey, blue looks dark," because blue might actually be dark. You can, however, make a picture grayscale, then turn that same grayscale picture into redscale, greenscale, and bluescale. The luminance would be exactly the same for every pixel, the only difference would be the pixel's color. I did that, in fact, and you know what? Your eyes rea…

Actually, your conclusion is incorrect. While there are fewer receptors for blue, each is much more sensitive. All you demonstrated is that the sRGB color model is blue deficient. See http://en.wikipedia.org/wiki/Color_vision and http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-... for details.

In particular, I'd like to draw your attention to the CIE 1931 chromatic diagram in the wikipedia link. This is supposed to represent the visible spectrum that the eye can see. The triangle is the sRGB colour space, what your monitor can reproduce. Notice how little blue the triangle contains? This is why your blue image looks so dark.

From the second link, it also turns out that CIE 1931 actually underestimates blue sensitivity. The book chapter discusses a corrected version called CIE 1978. It also has a plot of the eye sensitivity to various wavelengths. It turns out that our eyes are about as good at both blue and red, but more sensitive to green and yellow.

Experimentation is difficult. There are often a lot of factors you need to consider. Also, may I ask that you be a little less confrontational in the future? It's quite unnecessary. The majority of people here have good intentions.

edit: upon further research, it turns out it's even more complicated than just the sensitivity and cone numbers. Here: http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.ht... it states that we should still have less sensitivity to blue. However, we do perceive it to be the same intensity despite this. It appears that we do have difficulty determining details from blue objects, though. The reason is that most of the blue receptors are on the outer areas of the retina. It is a complex topic apparently.

Re: Your eyes suck at blue

#30

Post by [deleted] »

jemfinch wrote: post #28
bradleyland wrote: post #13

Earlier quoted context omitted.

The additive color model isn't exactly the same as the layer modes you'll see in image editing apps. This "mode" affects how the values of the current layer are applied to the layers below it. The normal mode is to replace the values below. When you switch to additive, the RGB channels from the current layer are "added" to the values of the layer below. This is entirely different than the concept of the additive colo…

> On a properly calibrated display, the display of RGB[0,255,0] and RGB[0,0,255] should have identical luminance values. It does, and your eyes still suck at blue. Why do you fight so vehemently against the scientific fact that your eyes have fewer blue receptors?

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