It's a way of taking taking a picture really quickly, by using information from the

Let's start with getting just one row of the picture.

To light up your subject, you shine a pulse of white light through a prism, so that the subject is lit up with a rainbow. So purple would be on the left edge of the subject, and red on the right edge.

The reflective parts of the subject would shine back the color more brightly, so a bump all the way on the left side would reflect a bright purple, and a hole at that spot would reflect a darker purple.

The rainbow pulse of light bounces off the subject, and is re-integrated into a pulse of white light by another prism. That pulse of white light is recorded.

So far, you only have a recording of a single pulse of a single dot of light. But that light has encoded in its colors the spatial information of the scene.

If you played back the white dot through a prism, you'd see the row of the subject reproduced. It would still be in a rainbow, but there'd be a bright purple spot on the left if there was a bump on the left of the subject. If you only pay attention to the values, you'll have reconstructed one row of an image of the scene in black-and-white.

Since you only sent out and recorded a single pulse of light, you were able to do it really quickly. So you can get a movie with a lot of frames per second by generating a sequence of the pulses.

To get more rows, you split up the spectrum you can deal with over the number of rows you want. So if you want two rows and you're using the spectrum of visible light, the first row would be lit up from purple to green, and the second row would be lit up from green to red. The color of the light you get back then tells you about the reflectivity of the subject not just from left to right, but also from top to bottom.

Now you have a whole 2d movie encoded as just single pulses of a single dot of light, with a huge framerate. If you want to digitize the information, rather than play it back through a prism steampunk style you conduct a Fourier analysis on the frequency distribution within each white dot to get a histogram.