The Observational Soundscape is a series of interactive sound installations developed by Zach Poff and me . 'Observe' in this context means both to sense through careful attention and to celebrate through practice. Each installation is designed to be spontaneous audio accompaniment for a public place, and each is adapted its location.

Using input from a video camera, a computer converts the activity of a space into a soundscape whose form and content reflect the visual and aural phenomena observed in the area. Every detected change in the space impacts the piece in some way: sometimes generating audio material and sometimes creating structural variation. The software translates the trends of color, density and motion from the video camera into the timing, pitch, and spatial characteristics of an audio composition. The result is broadcast through multiple speakers back into the space.

See Zach's thorough documentation here.