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Why we're blind to the color blue

calebkruse.com

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Re: Why we're blind to the color blue

#131

Post by cgufus »

Interesting article and discussion.

I always wondered how the focusing actually works. It happens „automatically“, but what is involved? Are all cone types used for the focusing, or mostly the green-type ones? Or are there even special, dedicated cells for the focusing only? Does the control ober the muscle controlling the lens shape goes via the brain, or is there a more direct mechanism?

Is there an expert around to explain or give some links to explanations?

(as a side comment: as a teenager I learned to control the focus point to a certain degree. There were these pattern-3D images, „Magic Eye“, and since the perceived depth does not correspond to the actual distance of the image, they eye needs to correct. I guess the same applies to 3D cinema, and may well cause the eye strain reported by many)

Re: Why we're blind to the color blue

#132

Post by ywain »

mrob wrote: post #33
crazygringo wrote: post #19

I don't believe the blurred images at the end have anything to do with eye focus, as the author suggests. After all, chromatic aberration is blurring of only a very, very small amount. The demonstrated seemingly negligible perceptual effect of blurring blue to a huge degree in a multicolor image doesn't seem to have anything to do with that, but rather the fact that we perceive primary blue as a much darker color tha…

See the very low coefficients for the blue channel when converting (gamma-compressed) RGB to luma. E.g. the common Rec. 709 standard assigns only 0.0722 weight to blue. Y' = 0.2126R' + 0.7152G' + 0.0722B'

This is basically the same as the Y component used in JPEG, right? Could the phenomenon described in the article be caused by the fact that they used JPEG images? I.e. would we observe the same thing happen with raw/uncompressed images?

Re: Why we're blind to the color blue

#133

Post by sgtnoodle »

crazygringo wrote: post #19

I don't believe the blurred images at the end have anything to do with eye focus, as the author suggests. After all, chromatic aberration is blurring of only a very, very small amount. The demonstrated seemingly negligible perceptual effect of blurring blue to a huge degree in a multicolor image doesn't seem to have anything to do with that, but rather the fact that we perceive primary blue as a much darker color tha…

I dunno, but when I look at glowing blue signs and blue Christmas lights at night, they look significantly more fuzzy than other color lights.

Re: Why we're blind to the color blue

#134

Post by munificent »

pionar wrote: post #86
smusamashah wrote: post #65

Earlier quoted context omitted.

I got dry eyes some time ago. Dryness gone but now I see starburst at night in headlights, neon signs and stars. Being unable to see stars as flickering dots anymore hurts me the most. Neon signs in particular if blue are totally whacky and unreadable until I go too close. I went to optometrist recently and they didn't understand why blue in particular and recommended a color blindness test which I obviously passed.…

Wait, stars are flickering dots for most people?

Yes, stars typically twinkle slightly.

Stars are unimaginably small point lights in the sky. They look like larger dots because of imperfect focus in our eyes [1]. But since they are in fact so tiny, it means very small atmospheric variation and obstruction—heat shimmer, floating dust, etc.—can significantly momentarily occlude the star. That causes its perceived brightness to vary over time.

[1]: https://en.wikipedia.org/wiki/Airy_disk

Re: Why we're blind to the color blue

#136

Post by soheil »

This is incredible on two grounds.

First, personal. I always thought something was wrong with my eyes because I couldn't focus on blue LEDs at night. I always thought either the LEDs have done irreversible damage to my eyes since some are so bright or that my eye is damaged some other way.

Second. This means we're missing so much about the world that we're not seeing. To be exact 33% or maybe even more if Earth has more blue than red and green, which I suspect it does last time I looked up.

Re: Why we're blind to the color blue

#137

Post by eurasiantiger »

pionar wrote: post #86
smusamashah wrote: post #65

Earlier quoted context omitted.

I got dry eyes some time ago. Dryness gone but now I see starburst at night in headlights, neon signs and stars. Being unable to see stars as flickering dots anymore hurts me the most. Neon signs in particular if blue are totally whacky and unreadable until I go too close. I went to optometrist recently and they didn't understand why blue in particular and recommended a color blindness test which I obviously passed.…

Wait, stars are flickering dots for most people?

What are they for you?

Re: Why we're blind to the color blue

#138

Post by eurasiantiger »

nimish wrote: post #15
atishay811 wrote: post #6

This is amazing to see. We should use this for image optimization. When we compress channels, we should compress the blue channel to like 30% while keeping others at fairly large 80% and it might appear better than a 60% compressed image.

That's chroma subsampling, most commonly 4:4:4 4:2:2 and 4:2:0 where this principle is used

I guess we can call it lossy compression ;)

Re: Why we're blind to the color blue

#139

Post by soheil »

abeppu wrote: post #36

There's an optometry place in my neighborhood with a back-lit sign with big, blue block letters. And every time I walk by at night I note how fuzzy it looks. I'm convinced this is an intentional troll. This optometrist knowingly picked a sign to make people momentarily question their vision.

Epic! Trolling or genius marketing while a bit misleading. At the same time if people can't clearly read the sign how do they know it's an optometry and that they need to go there?

Re: Why we're blind to the color blue

#140

Post by eurasiantiger »

emerged wrote: post #37
fotta wrote: post #20

Blue is my favorite color. Has my whole life been a lie?

Blue is my favorite color and it seems like whenever I call something blue somebody tells me it’s green. I don’t like green. I have no idea what to make of that.

If you can’t find a way to teal with it, try cyan turquoise?
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