Ambient Lapse

"Ambient Lapse" is a simple technique for capturing the ambiance of spaces, especially their color and spectral characteristics. It operates on a principle similar to long-exposure time-lapse, but allows exposures to overlap. Instead of producing momentary bursts of specific images, individual objects and well-defined perspectives, we're given vague impressions.

The general setup requires a video capture device, visual time-averaging/long-exposure/persistence of vision, and time-lapse. Sound can be stretched using any algorithm that preserves pitch. The video capture device is time-averaged for some large number of frames, and the average is taken as a time-lapse every so often for some smaller number of frames.

My implementation uses a webcam and shock-mounted stereo mic for capturing video and audio. Both are plugged into an IBM T40 via USB (the audio through an external sound card). The laptop is kept in my backpack, the camera is tied to the backpack, and the microphone is handheld. The system can run for about four hours on an old battery if optimized. I capture approximately 24 frames per second from the camera, average the last 128, and save to file the averaged frame every 24 frames.

The first ambient lapse was a 45 minute long improvised path. A more "complete" hour and a half path was planned out around Troy starting at the Approach and ending at the Folsom Library. I don't mean this specific path to be "the project", the project is the setup — I plan on exploring it through different paths in the future, especially in different cities. (I was really inspired by Oskar Fischinger's "Walking from Munich to Berlin" (1927), where he took single frames on a film camera of various places and people he met over the 1000 km, totaling 4 minutes).

Some things I've noticed after seeing the results of the first ambient lapse walk:

• Your perspective on future walks is modified. You gain intuitions about visual and aural phenomena over a larger time scale.
• You feel free to talk knowing it will be unintelligible and probably not even show up in the environment because you're such a small part of it.
• The lossless JPEG codec I use for encoding the video does not use any dithering, so the slow gradients produce color isolines on each frame — reminiscent of more traditional cartography. "Color maps" of environments.