Calibration and performance of a 3-dimensional television system for kinematic analysis.

A three-dimensional television system for kinematic analysis has been developed using television cameras connected to a digital computer. Reflective markers on the limbs of the subject are illuminated by stroboscopes, and show up as bright spots in the television image. A television/computer interface generates the two-dimensional coordinates of these spots, and stores them on disk for later analysis. A three-dimensional calibration procedure has been developed which requires an initial survey to be made of the measurement area, but thereafter takes only a few minutes to perform on a day-to-day basis. The television system has been in routine use for over a year, and it has proved rapid, reliable and easy to use, both for purely kinematic studies, and together with a pair of forceplates for combined kinetic/kinematic studies.