KINEMATICS - Biomechanics and Motor Control of Human Movement - page 59

Figure 3.12 Typical infrared television camera mounted permanently in a clinical gait
laboratory. The infrared lights form a “donut” shape around the lens and are pulsed for
a short time each frame to freeze the image prior to scanning. (Courtesy of the Gait
Analysis Laboratory, Connecticut Children's Medical Center, Hartford, CT.)
This camera is one of six to twelve cameras that could be mounted around
the gait laboratory. Thus, the reflected infrared light from the markers is the
only light that is picked up by the camera, and since it is a pulsed source,
the marker images are “frozen” in time. Figure 3.13 depicts such an arrange-
ment in a clinical gait laboratory along with the spherical reflective markers
mounted on a young patient.