Professor of Biomedical Engineering,
Diagnostic Radiology, and Electrical Engineering
Ph.D. 1982, University of Southern California
Phone: 1 (203) 785-2427
Fax: 1 (203) 785-4273
My research focuses on developing biomedical imaging as a powerful tool for improving understanding of basic anatomical and physiological relationships in normal and abnormal (e.g. disease) states and for accurate and reproducible clinical diagnosis.
I work with engineering and mathematical principles and rely largely on signal/image processing techniques from which I derive useful image feature information and capture model-based information in concise mathematical forms. I use nonlinear optimization methods to implement reasoning strategies. My image processing and analysis research can be divided into three general areas:
Segmentation of meaningful regions and/or objects in images. I look at deformable model-based approaches to boundary finding and aim at locating the complete boundary of a deformable object efficiently and reproducibly. I do this by incorporating basic structural or parametric models into an optimization-based search strategy. Initially, I aimed at 2D parametrized boundary finding, but now I am extending it into an approach for segmenting deformable surfaces from three-dimensional biomedical image data sets. Current applications include segmentation of the left ventricle of the heart from 4D cine Magnetic Resonance images (MRI) and segmentation of the temporal lobes of the brain from static MR images. Future research will focus on isolating structures using images obtained from laser-scanning confocal microscopes.
Image-based measurement and quantification of anatomical, physiological and/or clinically meaningful parameters. A primary example of this research is the tracking and modeling of non-rigid motion for the purpose of quantifying cardiac left ventricular (LV) regional function from 2-D and 3-D diagnostic image sequences. Such quantification permits measurements that are useful in understanding the basic relationships between the state of the heart muscle (myocardium) and overall LV function; these measurements can be important for managing patients with ischemic heart disease. My methodology makes use of mathematical models related to the motion of 3-D elastically deformable objects and is adaptable to the nonlinear, non-rigid regional motion of the LV.
Development of decentralized approaches for forming complete, integrated computer vision/image analysis systems. Dividing computer vision and image analysis systems into modular hierarchies is useful computationally and also allows to model particular image understanding tasks better. Hierarchical systems are necessary to perform such complex tasks as recognizing anatomy, quantifying the shape and motion of the heart, or performing an integrated segmentation of anatomical structures using multiple imaging modalities. I have recently developed an approach based on the mathematical concept of game theory, where functionals representing each module's tasks both compete and cooperate to make decisions about particular image analysis goals.
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