[MUSIC]
So, I am Sergio Nascimento.
I work on color vision for many years at Minho University in Portugal.
And I've tried to understand how we perceive colors and specifically and
been interested in the last few years how we perceive colors in paintings.
So one of the things I've been interested in is trying to quantify as I said,
the colors of paintings and try to perceive or
measure information that is invisible light that we cannot see.
So actually, our color vision is limited because we sample the visible spectrum
only in three regions, in the red, green and blue region of the spectrum.
And this means that the result of information
in the visual spectrum that we cannot see.
So the techniques that we use that are called Spectral Imaging,
they allows us to see much more than that.
So because they sample the visible spectrum in many more spectral bands.
So it's like if we have a system that has ten times more resolution than our eye for
colors.
So and we use that to digitalize paintings and
then to get more information from paintings and
we actually can see with our eyes.
This technique allows us to have a very detailed information from the painting,
spectral information.
So from each pixel of the painting, so from each small area of the painting,
we have a spectrum, a full visible spectrum.
And that allows us to do a lot of things, for
example allows us to compute very precisely the colors of the paintings.
And these computations can give
estimates of how many colors
we see in the paintings.
And then we can compare it for example for
the same painter,different paintings and how they evolve or
they change the technique to produce a certain number of colors.
So for example, there are painters that statically using colors but
in very limited ways, just some colors, a few colors.
And then they evolve to use many more colors and
to create the perception of many more colors in their paintings.
So another thing that we can do with this kind of data is to simulate
the painting is going to be perceived in different light sources.
For example, how it;s going to be perceived with LED or with a specific LED.
And that is very important because in the museums when they have to select a light
source for their paintings, they need to know what is the effect that the light
source is going to have on the painting, on the appearance of the painting.
How does spectral vision work in practice?
So we have one painting here that is illuminated so
we can see all sorts of colors.
And we have the spectral imaging system here.
What it does is to take multiple pictures at different wavelength bands,
different chromatic bands.
And with that information it builds spectrum for
each big cell for a small bit of the debating.
For example, this part here that is that you can see that is red,
we have the spectral information here.
So you can see the spectrum here that there's more intensity in
the red part of the spectrum.
So we have this information for all pixels of the painting.
So in summary, we can say that we can build the spectral fingerprint of
the painting with this data.