Free data set of the month: Imaging Spectroscopy

There's a lot of free data sets floating around the internet, and while things like funny cat videos and the results of color-naming surveys get a lot of play, many others don't get used for much. Recently I've been playing around with one such data set: images from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS).

I've always found it interesting that the way we perceive color is very different from how light actually works. Most of us have three different types of cones in our eyes and we perceive different colors as different combinations of stimuli to these three types of cones. In a very rough sense, when we look at a color, our brain gets three different numbers to figure out what it is. Light, on the other hand, is a bunch of photons with some distribution of wavelengths. To fully describe the light coming from an object you need a function that shows how many photons are at any given wavelength, which is way more complicated than just the three numbers we get.

So what about all that information that gets thrown away on the way to our brain? Are we missing out on a magical world of super-duper colors and wonder? Not really, but skip past the break anyways to find out more.

My Pepsi* Challenge

The basement of the Physics building has a Pepsi machine.  Over the course of two semesters Alemi and I have deposited roughly the equivalent of the GDP of, say, Monaco to this very same Pepsi machine (see left, with most of Landau and Lifshitz to scale).  It just so happens that Pepsi is now having a contest, called "Caps for Caps," in which it is possible to win a baseball hat.  There are several nice things about this contest.  Firstly, I drink a lot of soda.  Secondly, I like baseball hats.  So far so good.  Lastly (and most important for this post), is that it is fairly straightforward to calculate the statistics of winning (or at least simulate them).