Investigation of a new single projection technique for determination of 3D positions and orientations

We have developed a technique that can determine the three-dimensional (3D) position and orientation of an object from a single projection. In the iterative versions of this technique, a computer model of the known object is translated and rotated so as to align it optimally in a least-squares sense with the projection lines connecting the image points with the focal spot by using a modification of the projection-Procrustes technique. In previous studies, we found that the technique can determine the position and orientation of an object containing points distributed in x, y, and z to within approximately 0.3 degrees and 0.2 cm for RMS input image errors of 0.03 cm. In the current studies of this technique, we varied the distribution of points in our object along one dimension. We discovered that our technique can determine the position and orientation to within approximately 4 degrees and 0.2 cm for an object containing a distribution of points, even when the range in the distribution is only 0.5 cm. We believe that this technique will facilitate medical procedures by providing accurate 3D analysis of large as well as flat and narrow objects, such as catheters.