Your eyes suck at blue • Hacker News Board

Re: Your eyes suck at blue

#41

Post by bradleyland » Thu, Nov 11, 2010, 3:20 PM UTC

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?

I'm not arguing against for or against that fact. I'm arguing that these "testing" methodologies are flawed. I'm, apparently, doing a very poor job of expressing the distinction.

Let me state in as clearly as I can:

* A good test would ensure that the luminance values for all colors matched exactly throughout the test image.

* Said test would need to be displayed using a device that is calibrated to ensure displayed luminance matches encoded luminance.

* A test that pulls color data from a source image with mixed luminance values in each channel is flawed.

* This statement makes absolutely no claim as to the human ability perceive any of these colors.

Re: Your eyes suck at blue

#42

Post by bradleyland » Thu, Nov 11, 2010, 3:22 PM UTC

confuzatron wrote: post #36

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…

I'm sorry, but this is all irrelevant waffle. The issue is that the human eye is less able to distinguish detail in the blue spectrum, as the article (and a quick test) shows. (Blimey, I just noticed your first comment got 22 votes! Apparently irrelevant waffle gets upvoted on HN, if it sounds confident)

It's relevant because the testing method is flawed. Illustrating a fact using a flawed example/method is bad science.

Re: Your eyes suck at blue

#43

Post by confuzatron » Fri, Nov 12, 2010, 10:01 AM UTC

bradleyland wrote: post #42

confuzatron wrote: post #36

Earlier quoted context omitted.

I'm sorry, but this is all irrelevant waffle. The issue is that the human eye is less able to distinguish detail in the blue spectrum, as the article (and a quick test) shows. (Blimey, I just noticed your first comment got 22 votes! Apparently irrelevant waffle gets upvoted on HN, if it sounds confident)

It's relevant because the testing method is flawed. Illustrating a fact using a flawed example/method is bad science.

Sorry, no. You've really missed the point I'm afraid.

A little bit of knowledge, as they say...

Re: Your eyes suck at blue

#44

Post by punchagan » Sun, Nov 14, 2010, 4:47 AM UTC

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…

Here's a little experiment that I did. http://punchagan.muse-amuse.in/blog/do-our-eyes-suck-at-blue... I tried swapping channels, to cancel any unsymmetric effects like the use of Bayer filter etc. And still I find that the Green channel is always the most pixelated. The difference between Red and Blue channels is not all that perceivable.