From: Brandon Van Every Subject: TECH: Optical motion tracking for a Rave? Date: 27 Apr 1997 19:39:00 GMT Message-ID: <01bc52dd$12bc1f60$099f72ce@hammurabi.blarg.net> Organization: Blarg! Online Services - 206/441-9109 This group called the Pangaea Project is looking to put together an all-ages "Rave" in Seattle. Essentially, this will be like a nightclub which is mostly dark, but might have some flashing lights or other things going on. I'm thinking about doing some optical motion tracking in this environment. The idea would be to give people in the audience a fluorescent orange tag that they can wave around. A digital camera grabs image frames from the audience at 60 Hz, and a scanline algorithm is run on the input data to detect the orange blots within some range of tolerance. Just like a classical scanline rendering algorithm, only detecting instead of rendering. Construct a graph of the blot positions, attempt to relate blot positions between frames, and hey presto! you have some cheesy motion tracking. It's not essential for the motion tracking to get everything "right," or to record any depth info, as this data is only going to be used for artistic purposes. I guess it's not really motion tracking... it's more like the audience rendering 2D blots onto the camera surface. Well, 2D motion tracking. Problem: while at a club tonight, I realized just how much light interference there really can be. Sometimes someone strobes a white light. Other times there's ambient colored lights. Or else there are bright light sources like candles, or strobes coming from different directions. Mostly things are either "light" or "dark," but still, there's a good deal of interference going on. Although ideally I could help design the lighting so as to minimize interference, I expect Murphy's Law to operate in full. Consequently, I'd like to make the tag detection "robust." Anyone have any suggestions as to how to do this in a "noisy" lighting environment? Particular colors? Special reflective materials? Infrared? Thanks in advance, -- Brandon J. Van Every DEC Commodity Graphics http://www.blarg.net/~vanevery Windows NT Alpha OpenGL ------------------------------------------------------------------------ Seattle! Join the <<>> Monthly meetings at the Speakeasy. E-mail me for details....