To animate, visualize or interact with complex structures and processes, it is necessary to create models to represent these systems. Research in this area is thus aimed at developing models that exhibit sufficient mathematical and physical rigor to capture realism, and which can also support quantitative analysis as well as visual interpretation. The basic issues and key questions that underlie this research include:

• What mathematical and computational techniques can be used to create realistic models of complex geometrical structures or dynamic processes?
• How can physically based methods be incorporated into these models?
• How can the modeling algorithms be optimized to improve performance and to support highly interactive environments?
• Can models be created to achieve visual, behavioral, and interactive realism in an efficient manner?
• What models are appropriate for intuitive visualizations?

• Interactively deformable models to support surgery simulation.
• An algorithm, called Topological Goniometry, to estimate the orientation (or pose) of three-dimensional objects (DISHA).

Publications:

• "Interactively Deformable Models for Surgery Simulation,"
  with J. O'Brien. invited chapter in Medical Multimedia (with CD-ROM) by U. Liverpool and Intellect Ltd., Oxford, U.K, to appear.

• "Interactively Deformable Models,"
  N. Ezquerra and J. O'Brien. invited chapter in Force and Tactile Feedback for Virtual Reality, J. Wiley & Sons, New York, NY, to appear.

• "Knowledge-Guided Segmentation of 3D Cardiac Imagery,"
  N. Ezquerra and R. Mullick. In Press.

• "An Approach to 3D Pose Determination,"
  N. Ezquerra and R. Mullick. ACM Transactions on Graphics, Vol. 15, No. 2, pp. 99-120, April 1996.

• "Automatic Determination of the Orientation of the Heart from 3D SPECT Imaging,"
  R. Mullick and N. Ezquerra. IEEE Transactions on Medical Imaging, Vol. 14, No. 1, March 1995.

• "Clinical Evaluation of Automated Technique to Reorient Left-Ventricular Myocardium in Cardiac SPECT,"
  with R. Mullick, D. Cooke, and E. Garcia. Journal of Nuclear Medicine, Vol. 35, No. 5, 1994.

• "Evaluation of Automatic Technique to Reorient the LV Myocardium in Cardiac SPECT,"
  R. Mullick, N. Ezquerra, C. Cooke, et al. Soc. Nuclear Medicine 41st. Meeting, Orlando, June 1994.

• "Interactively Deformable Models for Surgery Simulation,"
  S. A. Cover, N. F. Ezquerra, J. F. O'Brien, et. al. IEEE: Computer Graphics and Applications, Vol 13, No 6., pp. 68-75, November 1993.

• "Automatic Segmentation of 3D Cardiac SPECT Data,"
  R. Mullick and N. F. Ezquerra. Proc. of the 12th IEEE Southern Biomedical Engineering Conference, pp. 40-42, New Orleans, LA, April 1993.

• "3D Visualization of Pose Determination: Application to SPECT Imaging,"
  R. Mullick and N. F. Ezquerra. Proc. of the Second Conference on Visualization in Biomedical Computing , Chapel Hill, NC, SPIE vol. 1808, pp. 445-452, October 1992.

• "Automatic Program for Determination of the Long Axis of the Left Ventricular Myocardium for Thallium-201 Tomographic Reconstruction,"
  C. Cooke, R. Folks, N. Ezquerra, and E. Garcia. Journal of Nuclear Medicine. Vol. 30, #5, p. 806, May 1989.