Need an idea for an awesome Node project?
Look no further.
A neural net is designed to work like a very very very basic human brain. It's made up of arrays and arrays of anywhere from a handful of neurons and synapses to thousands and thousands of them. The idea is that you have a 'neuron' for every individual input that you want to feed into the neural net. For a black and white 20x20 pixel image, that would be 400 pixels = 400 input 'neurons'. Then you also have output neurons that give you the neural net's response to the input. The end result is that you can draw a tree on your 20x20 grid, give it to the neural net, and tell it that the output for this pattern should be "tree".
And you train it with that image. Like 20k times. Then you give it other pictures of trees, and you tell it those are also "tree". Then you show it a house and tell it that's a "house". 20k times. Rinse and repeat. Cat, dog, fish, baseball, chair, flower. Every time you do this, the neural net adjusts (in human-speak) the level of neurotransmitters in the synapses, so that the next time the neurons around it fires, it knows how likely it is to be a certain picture.
Now you let someone draw an object in that 20x20 space. You ask the neural net what it is. And it tells you. It's a picture it's never seen before, but because it's been trained to recognize patterns and enough pixels are similar to what it's seen before, it knows.
This isn't limited to just image processing, of course -- you could feed it a user's purchasing history on an ecommerce site and get a prediction about what they'll buy next. You could give it identifying qualities of a song and have it tell you what song it is (this is, in fact, how many such services work). The list goes on.
If my description above was hard to follow, just hit that link and look at the API. It's (ironically enough) brainlessly easy. And the training is largely automated for you, which rocks.
I'd be playing with this constantly if I had the time... but I don't . So I want to see what you guys make with it xD