For the final in my Nature of Code class, I created an interactive video installation called Particle Mirror. I compare the pixel data between incoming frames from a video camera to detect motion. Wherever the change from one frame to the next is above a threshold value, I apply a vector force to a grid of spring-connected particles (I used the toxiclibs verlet physics library, and the spring mesh is adapted from Toxi’s softbody square example). The resulting image stretches and deforms in response to the viewer’s movements. The glowing effect of the particles is accomplished with a few calls to OpenGL that enable additive blending (Adapted from Robert Hodgin’s tutorial on that topic).

Overall, I was pretty pleased with the results. One of the things that people liked, which I hadn’t anticipated, was the ability to “effect” other people, without touching them physically – meaning, that by moving and stretching the spring field, one person could distort the body/image of the person standing next to them.

For future iterations, I’d like to make the distortion algorithm more accurate, possibly using optical flow (if anyone knows of any implementations of optical flow in Processing, give me a shout!).

Particle Mirror will be in the upcoming ITP Spring Show. If you’re in NYC, stop by and check it out.

Update: Apologies for the delay, but here is the Processing sketch for those who were interested.