function [T,res]=soder(data)
Description: Program calculates the transformation matrix T containing
the rotation matrix (3x3) and the translation translation
vector d (3x1) for a rigid body segment using a singular
value decomposition method (Soederkvist & Wedin 1993).
Input: data: columns represent the XYZ positions and the rows
represent time.
Output: T: 4x4 Matrix containing the rotation matrix R and the
translation d: T = [R,d; 0 0 0 1]
res: norm of residuals (measure of fit; "rigidity" of body
References: Soderkvist I. and Wedin P. -A., (1993). Determining the
movements of the skeleton using well-configured markers.
Journal of Biomechanics, 26:1473-1477
Author: Christoph Reinschmidt, HPL, The University of Calgary
(Matlab code adapted from Ron Jacobs, 1993)
Date: February, 1995
Last Changes: December 09, 1996
Version: 3.1