Rigid-Body Motion Estimation Using Statistical Solid Dynamics Method and Dynamic Method

The most frequently used method in three dimensional human gait analysis involves placing markers on the skin of the analyzed segment. This introduces a significant artifact which strongly influences the bone position and orientation and joint kinematics estimates. The benefit in developing a method to reduce soft tissue artifacts is significant, resulting in the prevention, better diagnosis, and treatment of joint disorders and in the design of better prosthetic devices with longer mean times to failure. In this work we approached the problem of soft tissue artifacts from both a dynamic method and a statistical solid dynamics method. The dynamic method is based on the implementation of a Lagrangian approach to drive model based procedure for the estimation of the rigid body (bone) motion for the measurements of markers attached to the skin. The statistical solid dynamics method is a combination of several existent tools. It is based on a least squares optimization of markers position and orientation. Both methods were tested and evaluated using computer simulation and similar dynamics systems.