Fred L. Fontaine

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We consider the problem of detection of edges in an the initial condition u(x , y , 0) and the variance of the smoothing image by solving an anisotropic diffusion equation, which has the Gaussian plays the role of the time variable t . The difficulties intrinsic property that low-contrast regions are smoothed and highassociated with discerning true edges(More)
Commercial receivers used for parallel MR imaging often present researchers with hurdles such as high cost-per-channel, low scalability for multiple coils and non-accessibility to intermediate data for research. A novel low-cost multichannel digital receiver for use with MR scanners has been developed to alleviate these concerns. MR signals from up to 16(More)
— Common MRI sampling patterns in kspace, such as spiral trajectories, have nonuniform density and do not lie on a rectangular grid. We propose mapping the sampled data to a pseudo-hex lattice, taking advantage of its approximate isotropic nature in k-space and square nature in the reconstructed image space. The group structure of the lattice is exploited(More)
Common MRI sampling patterns in k-space, such as spiral trajectories, have nonuniform density and do not lie on a cartesian grid. This paper illustrates that the sampled data on a spiral trajectory can be e¢ ciently regridded onto a pseudohexagonal lattice using a nearest neighbor regridding algorithm. Also, it is shown that separable FFT using cartesian(More)
MR. IMAGER is a novel multi-channel Magnetic Resonance Imaging (MRI) front-end. It connects to an MRI scanner and digitally processes raw magnetic field measurements into images of the body. Innovative data acquisition techniques are used, with all digital functions integrated onto a single Field-Programmable Gate Array (FPGA). The result is a device that(More)
In many imaging applications, including sensor arrays, MRI and CT,data is often sampled on non-rectangular point sets with non-uniform density. Moreover, in image and video processing, a mix of non-rectangular sampling structures naturally arise. Multirate processing typically utilizes a normalized integer indexing scheme, which masks the true physical(More)
guidance during the preparation of this thesis. Mr. Henry Massalin supplied the GIF decoder used, answered many questions, and in general was a good influence on me. Dr. Leonid Vulakh helped with some of the theory. I would also like to thank the Cooper Union librarians for tracking books down for me and also furnishing many of the pictures used in the(More)
Parallel MRI acquisitions are generally reconstructed into images off-line, on PCs and computer clusters. Here, we present an innovative single-FPGA engine that performs realtime 2D-FFT image reconstruction from arrays of up to 16 coils. Partial reconfiguration enables rapid switching of FPGA modules for maximal flexibility and lower hardware cost. If the(More)
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