A quick and accurate way to rotate and shift nuclear magnetic resonance (NMR) images using the two-dimensional chirp-z transform is presented. When the desired image grid is rotated and shifted from the original grid due to patient motion, the chirp-z transform can reconstruct NMR images directly onto the ultimate grid instead of reconstructing onto the original grid and then applying interpola...

A fast and accurate algorithm for the reinitialization of the signed distance function in two and three spatial dimensions is presented. The algorithm has computational complexity O(N logN) for the reinitialization of N grid points. The order of accuracy of the reinitialization is demonstrated to depend primarily on the interpolation algorithm used. Bicubic interpolation is demonstrated to resu...

In this paper we address the problem of producing an enlarged picture from a given digital image (zooming). We propose a method that tries to take into account information about discontinuities or sharp luminance variations while doubling the input picture. This is realized by a multiple scan of the zoomed image and could hence be implemented with limited computational resources. The algorithm ...

Assumptions about image continuity lead to oversmoothed edges in common image interpolation algorithms. A wavelet-based interpolation method that imposes no continuity constraints is introduced. The algorithm estimates the regularity of edges by measuring the decay of wavelet transform coefficients across scales and preserves the underlying regularity by extrapolating a new subband to be used i...

We present a novel feature-based image interpolation approach. Two continuous maps for the image domain are constructed via an L-gradient flow based on their multi-resolution representations so that the features of the given images are matched at multiple scales. The flow equation is efficiently solved using a finite element method in the bicubic B-spline vector-valued function space. The inter...

Several efficient constructions of smooth surfaces following the outlines of a polyhedral mesh are based on three-sided patches. To demonstrate that these constructions arc compatible with existing software based on tensor-product patches, the particular scheme in [3] is expressed in terms of linearly-trimmed bicubic patches. Explicit formulas relating the coefficients of the patches to the ver...

This paper describes a fast algorithm for scattered data interpolation and approximation. Multilevel B-splines are introduced to compute a C 2 -continuous surface through a set of irregularly spaced points. The algorithm makes use of a coarse-tofine hierarchy of control lattices to generate a sequence of bicubic B-spline functions whose sum approaches the desired interpolation function. Large p...

The various up-sampling techniques available in the literature produce blurring artifacts in the upsampled, high resolution images. In order to overcome this problem effectively, an image fusion based interpolation technique is proposed here to restore the high frequency information. The Discrete Cosine Transform interpolation technique preserves low frequency information whereas Discrete Sine ...