Projection-based registration of radiological images1

This paper introduces a projection-based method for registration of radiological images. The proposed method estimates the scale, translation and rotation parameters which define the global affine motion of an image with respect to a reference image. Using these estimated parameters, radiological images can be properly re-aligned to help diagnosis. The proposed method tries to match the horizontal and vertical projections of the image to be registered with the corresponding projections of the reference image in a hierarchical manner. After coarse estimates of the parameters are obtained using low resolution images, higher resolution images are utilized for the refinement of the parameter estimates. The experiments carried out on Computed Tomography (CT) and Magnetic Resonance (MR) images show that the performance of the algorithm in estimating the affine motion parameters is encouraging.