An optical system tracks the motion of objects, including the human body or portions thereof using a plurality of three-dimensional active markers based upon triangulation from data read via multiple linear CCDs through cylindrical lenses. Each marker is lit in sequence so that it is in sync with a frame capture using the imaging system positioned and oriented so as to provide a basis for computing three-dimensional location. In the preferred embodiment, the imaging system detects an infrared signal which is sent out by the tag controller as part of the tag/marker illumination sequence at the beginning of the first tag position capture time. The controller then traverses through the tags in time sync with each imaging system frame capture cycle. Thus, only one unique tag will be lit during each image capture of the cameras, thereby simplifying identification. Using linear CCD sensors, the frame time (i.e. point acquisition time) is very short, allowing very many markers to be sampled and located sequentially in real time.