Thread

1. vermarish · 1785859472 · focus · HN ↗

   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 executed by hand.

   Lastly, I love the presentation of sampling from different r values. Whether you sample from a fixed r value or a range of r values, I bet this has great applications in game design or animation.

   I still don't quite get the manual data labeling process at the beginning? It seems like it would encode some bias, but the consistency of the first point cloud and the results certainly speak for themselves.

   1. dr_scully · 1785860437 · focus · HN ↗

      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.

      <a href="https:&#x2F;&#x2F;discovery.ucl.ac.uk&#x2F;id&#x2F;eprint&#x2F;10093345&#x2F;" rel="nofollow">https:&#x2F;&#x2F;discovery.ucl.ac.uk&#x2F;id&#x2F;eprint&#x2F;10093345&#x2F;

      1. dTal · 1785861922 · focus · HN ↗

         Oh goody, an expert in a question I&#x27;ve always wanted to ask.

         Once upon a time, I encountered a sort of interactive museum book called &quot;Earthsearch&quot;. One of its &quot;exhibits&quot; was a color wheel, made of two spinnable pieces of tinted acetate, that purported to be able to generate any skin tone. I suppose this is three degrees of freedom, since for any position of the two wheels you could access a range of colors around the edge - but the printed page underneath was simply a grayscale gradient, so one degree of freedom was simply luminance.

         The book was released in 1994, and was very confident. It even went as far as to encourage the reader to see a doctor, should their skin tone not be achievable! What color model were they using?

         1. mhink · 1785863489 · focus · HN ↗

            Oh man, that&#x27;s a blast from the past, I think I had that book! Was that the one with an aluminum cover?

            1. dTal · 1785864912 · focus · HN ↗

               That&#x27;s it! They (rather dubiously) claimed it came from a recycled Russian coke can, if I recall.

               1. vector_spaces · 1785892871 · focus · HN ↗

                  I had that one too. I remember I used to crunch on the rice from the bag it came with (I was like 8).

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