Two-dimensional rigid-body kinematics using image contour registration.
A method for calculating two-dimensional rigid-body kinematic parameters using shape features is presented. Proposed applications include the noninvasive quantification of planar joint motion in vivo. By using digitized images (computed tomographs, radiographs, etc.) of a bone contour at two positions, the contour curvatures can be 'best-fit' to obtain a one-to-one mapping or registration of the bone images. This produces a dense field of displacement vectors from which planar rigid-body kinematic parameters can be estimated. Accuracy was studied using radiographic images of cadaveric femoral bone. The two motions of pure rotation with a fixed center of rotation and of pure translation were simulated. For pure rotation, error in rotation was independent of the rotation magnitude, with an average (n = 10) error of 0.3 +/- 0.8 degrees. The translation error averaged 0.9 +/- 0.5 mm. For pure translation, the error in rotation was -0.01 +/- 0.69 degrees and the error in translation was -0.62 +/- 0.98 mm (n = 10). This novel method has broad applications in the field of planar kinematics, especially in cases for which marker fixation is neither possible nor practical.
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06510.
J J
JJ
Crisco
K
K
Hentel
S W
SW
Wolfe
J S
JS
Duncan
D000465:Algorithms; D003198:Computer Simulation; D005269:Femur / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D005583:Fourier Analysis; D006621:Hip Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008954:Models, Biological; D009068:Movement; D011856:Radiographic Image Enhancement; D016059:Range of Motion, Articular / Q000502:physiology; D012399:Rotation