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dr_scully

95 karma · joined February 9, 2022

https://www.linkedin.com/in/timothy-scully
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dr_scully··on Tao: Open math problems being non-renewably mined by AI
I think the main point is the ubiquity of AI intelligence. If there is a human far surpassing me, but unavailable to me, then I have to work through it myself. If the answer is a prompt away, then why bother.
dr_scully··on GPT-6 Astra
He also made a video on the same topic for Big Think: https://news.ycombinator.com/item?id=49551848
dr_scully··on Show HN: Simple algorithm and color space to generate diverse skin tones
In theory, you can construct a skin model of any condition you want. It would be a case of knowing the concentration, scattering profiles and reflectance spectra of any chromophores. For the thesis, I wrote a Monte Carlo skin simulator using OpenCL, when it has just come out. You could plug anything in there.
dr_scully··on Show HN: Simple algorithm and color space to generate diverse skin tones
That’s sounds very interesting. I’m not sure. In the thesis, I generated spectral curves and transformed them using the light and camera sensitivity curves. So, in theory it could be used in any color space.

But I can’t vouch for the accuracy of the book, but I suspect it was an approximation.

The haemoglobin and melanin are roughly in separate layers of the skin. There is an approximation known as Beer-Lambert that models the skin as two semi-transparent layers. This ignores subsurface scattering, but is roughly correct.

So, in theory two acetate sheets might replicate this. That’s my intuitive opinion. It has been many years since I did this work.

dr_scully··on Show HN: Simple algorithm and color space to generate diverse skin tones
We used the approximation that the hypodermis was a perfectly white reflector; so the thickness wouldn’t matter. The collagen fibrills scatter light in such a way to create a yellower tint. So a person’s skin might appear this way in the absence of melanin and haemoglobin. I’m not an expert on population statistics, and so cannot give an opinion on specific skin types. Everything was based on ranges.

There is a separate effect of increased bilirubin content, that would appear if someone was ill.

dr_scully··on Show HN: Simple algorithm and color space to generate diverse skin tones
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/

dr_scully··on GPT Unicorn: A Daily Exploration of GPT-4's Image Generation Capabilities
If you ask it to write GLSL code implementing Signed Distance Fields, it can generate a 3D rendering of a unicorn as well. Just paste it into ShaderToy. I asked it to implement animation as well, for the legs, and it manage to do something although incorrect.