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SUMMARY:Geodesic methods for Biomedical Image Segmentation - Cohen\, L (Un
 iversit Paris-Dauphine)
DTSTART:20110825T080000Z
DTEND:20110825T084500Z
UID:TALK32492@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Tubular and tree structures appear very commonly in biomedical
  images like vessels\, microtubules or neuron cells. Minimal paths have be
 en used for long as an interactive tool to segment these structures as cos
 t minimizing curves. The user usually provides start and end points on the
  image and gets the minimal path as output. These minimal paths correspond
  to minimal geodesics according to some adapted metric. They are a way to 
 find a (set of) curve(s) globally minimizing the geodesic active contours 
 energy. Finding a geodesic distance can be solved by the Eikonal equation 
 using the fast and efficient Fast Marching method. In the past years we ha
 ve introduced different extensions of these minimal paths that improve eit
 her the interactive aspects or the results. For example\, the metric can t
 ake into account both scale and orientation of the path. This leads to sol
 ving an anisotropic minimal path in a 2D or 3D+radius space. On a differen
 t level\, the user interaction can be minimized by adding iteratively what
  we called the keypoints\, for example to obtain a closed curve from a sin
 gle initial point. The result is then a set of minimal paths between pairs
  of keypoints. This can also be applied to branching structures in both 2D
  and 3D images. We also proposed different criteria to obtain automaticall
 y a set of end points of a tree structure by giving only one starting poin
 t. More recently\, we introduced a new general idea that we called Geodesi
 c Voting or Geodesic Density. The approach consists in computing geodesics
  between a given source point and a set of points scattered in the image. 
 The geodesic density is defined at each pixel of the image as the number o
 f geodesics that pass over this pixel. The target structure corresponds to
  image points with a high geodesic density. We will illustrate different p
 ossible applications of this approach. The work we will present involved a
 s well F. Benmansour\, Y. Rouchdy and J. Mille at CEREMADE.\n
LOCATION:Seminar Room 1\, Newton Institute
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