Dennis Healy

Research Interests

Applied Mathematics, Signal Processing, Medical Imaging, and Nonlinear Optics

A Few Recent Publications

  • Reduced Motion Artifacts in Medical Imaging by Adaptive Spatio-Temporal Reconstruction

    • In this paper we introduce an algorithm for imaging a time varying object f(\vec{x},t), from its projections at different fixed times. This algorithm differs from other algorithms in that we do not need the object to remain stationary during the data acquisition period. We show that the reconstruction of coarse features, corresponding to low spatial-frequency data, can be made nearly instantaneously in time from the evolving data. A temporal sequence of these low spatial-frequency reconstructions can be used to estimate the motion of the object. Once the motion is estimated, we may use the estimate to compensate for some of the motion of fine scale features. This enables accurate reconstructions of the time varying fine structure in several cases. The algorithm is demonstrated for a selection of phantoms and actual MRI studies. In general, this technique shows promise for a wide variety of applications in MRI, as well as for heart imaging using x-ray CT. Clinical applications should include both functional MRI such as dynamic imaging of oxygen usage and blood flow in the brain, and motion imaging of joints, angiography in the lungs, and heart imaging.

  • Applications of time-frequency bases to multiple access fiber optic communication systems

    • In this paper we present background material concerning the propagation of pulses through fiber optics, and current transmission schemes in fiber optics. We discuss the value of using different signal processing techniques, and time-frequency bases in Fiber Optic Transmission. Finally we will outline methods which allow one to send optical pulses with arbitrary shapes through fiber optics.

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