1999 Volume 43 Issue 6 Pages 1056-1066
We developed a kinematic method of calculating virtual points that could not be observed directly, such as condyle, molars, and the body of mandible, utilizing a motion capture system (Vicon 370, Oxford Metrics). In this study, the accuracy of the system was examined and kinematic data from test subjects were presented.
Methods: Retro-reflective markers were placed on digital vernier calipers (Digimatic Caliper: CD-15 C, Mitutoyo). In addition, marker frames on which 3 markers were arranged spatially were attached to the slider of the calipers to provide a measured value of virtual points that were indicated by a stick on which 2 markers were aligned (pointers). Markers on the calipers were located and automatically tracked using six video cameras (V-133, nac) while the slider was displaced within the range of 150 mm in random directions and intervals. The video data were collected with a datastation and the three-dimensional (3 D) coordinated data were transferred to a computer. Measurements of virtual points, which were calculated from displacement of the marker frame attached to the slider, were combined with the video data of the markers.
Results: High linearity was observed both in markers and virtual points during displacement of the slider. Error that was calculated from discrepancy between measurements on the calipers and the Vicon were 0.11%(marker points) and 0.35%(virtual points) respectively.
