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.
Crisco
J J
JJ
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06510.
Hentel
K
K
Wolfe
S W
SW
Duncan
J S
JS
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