Now showing items 1-20 of 106

    • 3-D Reconstruction of Shaded Objects from Multiple Images Under Unknown Illumination 

      Jin, Hailin; Wang, Dejun; Cremers, Daniel; Prados, Emmanuel; Yezzi, Anthony; Soatto, Stefano (Georgia Institute of TechnologySpringer Verlag, 2008-03)
      We propose a variational algorithm to jointly estimate the shape, albedo, and light configuration of a Lambertian scene from a collection of images taken from different vantage points. Our work can be thought of as extending ...
    • 3D brain segmentation using dual-front active contours with optional user interaction 

      Li, Hua; Yezzi, Anthony; Cohen, Laurent D. (Georgia Institute of TechnologyHindawi Publishing Corporation, 2006-06)
      Important attributes of 3D brain cortex segmentation algorithms include robustness, accuracy, computational efficiency, and facilitation of user interaction, yet few algorithms incorporate all of these traits. Manual ...
    • 3D Topology Preserving Flows for Viewpoint-Based Cortical Unfolding 

      Rocha, Kelvin R.; Sundaramoorthi, Ganesh; Yezzi, Anthony (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2007-10)
      We present a variational method for unfolding of the cortex based on a user-chosen point of view as an alternative to more traditional global flattening methods, which incur more distortion around the region of interest. ...
    • Active contours for visual tracking: a geometric gradient based approach 

      Kumar, Arun; Yezzi, Anthony; Kichenassamy, Satyanad; Olver, Peter; Tannenbaum, Allen R. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 1995-12)
      In this note, we analyze the geometric active contour models proposed in [5, 191 from a curve evolution point of view and propose some modifications based on gradient flows relative to certain new metrics. This leads to a ...
    • Active Geodesics: Region based Active Contour Segmentation with a Global Edge based Constraint 

      Appia, Vikram; Yezzi, Anthony (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2011-11)
      We present an active geodesic contour model in which we constrain the evolving active contour to be a geodesic with respect to a weighted edge-based energy through its entire evolution rather than just at its final state ...
    • Anti-geometric diffusion for adaptive thresholding and fast segmentation 

      Manay, Siddharth; Yezzi, Anthony (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2003-11)
      In this paper, we utilize an anisotropic diffusion model, which we call the anti-geometric heat flow, for adaptive thresholding of bimodal images and for segmentation of more general greyscale images. In a departure from ...
    • Anti-Geometric Diffusion for Adaptive Thresholding and Segmentation 

      Manay, Siddharth; Yezzi, Anthony (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2001-10)
      In this paper, we present a novel adaptive thresholding technique based upon an anisotropic diffusion model, which may be referred to as the anti-geometric heat flow. In contrast to its more popular counterparts (such as ...
    • Audio-Visual Flow - A Variational Approach to Multi-Modal Flow Estimation 

      Hamid, Raffay; Bobick, Aaron; Yezzi, Anthony (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2004-10)
      Just as a motion field is associated to a moving object, an audio field can he associated to an object that can behave as a sound source. The flow field of such a sound source which moves over time would not only have an ...
    • Brain MRI T₁-Map and T₁-weighted Image Segmentation in a Variational Framework 

      Cheng, Ping-Feng; Steen, R.Grant; Yezzi, Anthony; Krim, Hamid (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2009-06)
      In this paper we propose a constrained version of Mumford- Shah’s[1] segmentationwith an information-theoretic point of view[2] in order to devise a systematic procedure to segment brain MRI data for two modalities of ...
    • Coarse-to-Fine Segmentation and Tracking Using Sobolev Active Contours 

      Sundaramoorthi, Ganesh; Yezzi, Anthony; Mennucci, Andrea C. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2008-05)
      Recently proposed Sobolev active contours introduced a new paradigm for minimizing energies defined on curves by changing the traditional cost of perturbing a curve and thereby redefining gradients associated to these ...
    • A Compact Formula for the Derivative of a 3-D Rotation in Exponential Coordinates 

      Gallego, Guillermo; Yezzi, Anthony (Georgia Institute of TechnologySpringer, 2014-08)
      We present a compact formula for the derivative of a 3-D rotation matrix with respect to its exponential coordinates. A geometric interpretation of the resulting expression is provided, as well as its agreement with ...
    • Conformal Metrics and True "Gradient Flows" for Curves 

      Yezzi, Anthony; Mennucci, Andrea (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2005-10)
      We wish to endow the manifold M of smooth curves in Rn with a Riemannian metric that allows us to treat continuous morphs (homotopies) between two curves c0 and c1 as trajectories with computable lengths which are independent ...
    • Curious snakes: an active contour formulation of information-driven minimum-latency boundary detection 

      Soatto, Stefano; Sundaramoorthi, Ganesh; Yezzi, Anthony (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2010-06)
      We present a region-based active contour detection algorithm for objects that exhibit relatively homogeneous photometric characteristics (e.g. smooth color or gray levels), embedded in complex background clutter. Current ...
    • A curve evolution approach to smoothing and segmentation using the Mumford-Shah functional 

      Tsai, Andy; Yezzi, Anthony; Willsky, Alan S. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2000-06)
      In this work, we approach the classic Mumford-Shah problem from a curve evolution perspective. In particular we let a given family of curves define the boundaries between regions in an image within which the data are modeled ...
    • Curve evolution implementation of the Mumford-Shah functional for image segmentation, denoising, interpolation, and magnification 

      Tsai, Andy; Yezzi, Anthony; Willsky, Alan S. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2001-08)
      In this work, we first address the problem of simultaneous image segmentation and smoothing by approaching the Mumford–Shah paradigm from a curve evolution perspective. In particular, we let a set of deformable contours ...
    • Curve Evolution Models for Real-Time Identification with Application to Plasma Etching 

      Berg, Jordan M.; Yezzi, Anthony; Tannenbaum, Allen R. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 1999-01)
      It is desirable, in constructing an algorithm for real-time control or identification of free surfaces, to avoid representations of the surface requiring mesh refinement at corners or special logic for topological transitions. ...
    • Curve Evolution, Boundary-Value Stochastic Processes, the Mumford-Shah Problem, and Missing Data Applications 

      Tsai, Andy; Yezzi, Anthony; Willsky, Alan S. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2000-09)
      We present an estimation-theoretic approach to curve evolution for the Mumford-Shah problem. By viewing an active contour as the set of discontinuities in the Mumford-Shah problem, we may use the corresponding functional ...
    • Deform PF-MT: Particle Filter With Mode Tracker for Tracking Nonaffine Contour Deformations 

      Vaswani, Namrata; Rathi, Yogesh; Yezzi, Anthony; Tannenbaum, Allen R. (Georgia Institute of TechnologyInstitute of Electrical and Electronics Engineers, 2010-04)
      We propose algorithms for tracking the boundary contour of a deforming object from an image sequence, when the nonaffine (local) deformation over consecutive frames is large and there is overlapping clutter, occlusions, ...
    • Detection of curves with unknown endpoints using minimal path techniques 

      Kaul, Vivek; Tsai, Yichang; Yezzi, Anthony (Georgia Institute of TechnologyBMVA Press, 2010-09)
      We present a novel method to detect curves with unknown endpoints using minimal path techniques. Our work builds on the state of the art minimal path techniques currently used to detect curves. Existing algorithms in the ...
    • Dynamic shape and appearance modeling via moving and deforming layers 

      Jackson, Jeremy D.; Yezzi, Anthony; Soatto, Stefano (Georgia Institute of TechnologySpringer Verlag, 2008-08)
      This model is based on a collection of overlapping layers that can move and deform, each supporting an intensity function that can change over time. We discuss the generality and limitations of this model in relation to ...