| The registration method presented in this thesis does not require an initial estimation of the transformation, and avoids problems of the classical iterative techniques by employing the multi-dimensional Fourier transform, which decouples the estimation of rotational parameters from the estimation of the translational parameters. Using the magnitude of the Fourier transform, an axis of rotation is estimated by determining the line that contains the minimal energy differential between two rotated 3-D images. By using a coarse to fine approach, the angle of rotation is determined from the minimal sum squared difference between the two rotated image. As the Fourier transform introduces hermitical symmetry in the rotation, the proper solution is identified through the use of a phase-correlation technique, and the estimate of translation is simultaneously obtained. Experimental results illustrate the accuracy that can be achieved by the proposed registration technique and performance is compared with that of the classical iterative closest point method. |
