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Show HN: Simple algorithm and color space to generate diverse skin tones

toneyalexander.github.io

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Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#21

Post by compass_copium »

automatoney wrote: post #12
andai wrote: post #7

Nice. Most of these colors look right to me, but I'm also seeing green, blue and purple? If you're curating colors from the space manually then it's not a problem. "Only realistic colors" would be a different problem. And I'm not sure if there's a way to solve that problem without excluding some real colors too. (Maybe if the colour selector was a different shape? I don't know much about color spaces.)

Yes absolutely right on - I mention much deeper in the page that in a picker UI you can use a bigger range, but that in a generation context you might want to be a bit more selective. I go into it a bit more when I explain what R^2 is. "not sure if there's a way to solve that problem without excluding some real colors too" - 100% right on that too. A big part of this work was to define a way to tweak/improve the equa…

I would have "show sphere" on by default--this kind of threw me at first, too.

This is a really nice project. Great work and a great write-up. Thanks for sharing.

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#22

Post by 4848489449 »

Tossrock wrote: post #10
moralestapia wrote: post #6

[flagged]

...Did you read the article, or use the picker? It's a continuous (up to the limits of RGB quantization) space which includes thousands upon thousands of shades of black. The selected tones at the top of the article are random and change continuously.

[flagged]

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#23

Post by dr_scully »

vermarish wrote: post #11

This is beautiful work! First, I thought this would involve using PCA to go from 3D to 2D, which would result in an easier selector to use, but at the expense of representing every person. Then, I thought this would stop at using the U-space vectors (the ones that form the basis of the PCA image) and their corresponding ellipse to form our color space, but no, the function fitting is a very slick idea, even if it was…

If you look at my doctoral thesis, in fact skin colour can be parametrised using melanin and haemoglobin concentration; which it means it is indeed (roughly) two dimensional. This allows you to invert the colour of a pixel and identify someone’s chromophore concentration. This is based on previous work of others cited in the thesis.

https://discovery.ucl.ac.uk/id/eprint/10093345/

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#24

Post by ptsneves »

On the movie Dolemite by Eddy Murphy, they go over the fact that black people absorb light and white people reflect, and how that changes the motion picture shooting process totally. Also how one size does not fit all. Cool project! I am not much into the humanities part of the project. For me this is as natural as having a localization framework, just in this case for skin tones.

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#26

Post by GolDDranks »

dr_scully wrote: post #23
vermarish wrote: post #11

This is beautiful work! First, I thought this would involve using PCA to go from 3D to 2D, which would result in an easier selector to use, but at the expense of representing every person. Then, I thought this would stop at using the U-space vectors (the ones that form the basis of the PCA image) and their corresponding ellipse to form our color space, but no, the function fitting is a very slick idea, even if it was…

If you look at my doctoral thesis, in fact skin colour can be parametrised using melanin and haemoglobin concentration; which it means it is indeed (roughly) two dimensional. This allows you to invert the colour of a pixel and identify someone’s chromophore concentration. This is based on previous work of others cited in the thesis. https://discovery.ucl.ac.uk/id/eprint/10093345/

I've heard that the so-called "yellowish" skin color that non-tanned East Asians tend to have, is due to relative abundance of subcutaneous fat. If that's true, is that captured by the haemoglobin dimension or is it a yet another degree of freedom?

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#29

Post by bellowsgulch »

Skin is so interesting as a surface to think about how light passes through and bounces off of.

There is at least one article published by a technical artist at Pixar who describes modeling a skull within a human scan so that subsurface lighting is more accurately rendered.

I suspect you could combine this with dr_scully’s comment and GolDDranks’ to reach the nuance involved in long tail realism details.

Re: Show HN: Simple algorithm and color space to generate diverse skin tones

#30

Post by automatoney »

rrradical wrote: post #28

Very neat project. Could I use this code to generate skin tones in my own project? Or more meant to just be educational/inspirational? I guess I'm wondering if you've considered adding a license.

Good catch, added MIT license - feel free to use it! On top of that, my understanding is that math/equations are not subject to copyright, so the core part of this work (the equations/ideas) I think legally has 0 limitations - even if there were a restrictive license. But IANAL so might have some misconceptions.
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