Ron Fischer reports on Virtual Sets, Digital Actors, Motion Capture, etc. There's not much new under the sun as regards basic technology for motion capture. While software has benefited greatly from cheap increases in processing power, hardware has not changed very much. However, the Reactor motion capture system, developed in the UK and now marketed by Ascension Technologies, has managed a novel approach to real-time optical capture.
Reactor is an active marker optical motion capture system.
Small discs covered with infrared LEDs are attached to significant points on a performer's body. He or she wears a small belt pack which flashes the discs sequentially at a rate of 900 flashes per second. Determining where the pulses are in 3D space is the task of the remainder of the system. To explain how Reactor is different, we'll summarize the way popular passive optical systems determine marker position. A number of modified video cameras observe the markers and correlate their 2D images to determine 3D positions.