Gradient Vector Flow Snake

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Gradient Vector Flow Snake

• C. Xu and J. L. Prince
• Project Proposal by Charlie Neo

2
Problem Description

• Finding Object Boundaries
• Snake (Active Contour) is extensively used
• Initialization
• Poor convergence to boundaries concavities

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Previous Work

• M. Kass, A. Witkin, and D. Terzopoulos, Snakes
  Active contour models, Int. J. Comput. Vis.,
  vol. 1, pp. 321331, 1987.
• V. Caselles, R. Kimmel, and G. Sapiro, Geodesic
  active contours, in Proc. 5th Int. Conf.
  Computer Vision, 1995, pp. 694699.
• L. D. Cohen, On active contour models and
  balloons, CVGIP Image Understand., vol. 53, pp.
  211218, Mar. 1991.
• C. Xu and J. L. Prince, Snakes, Shapes, and
  Gradient Vector Flow,'' IEEE Transactions on
  Image Processing, 7(3), pp. 359-369, March 1998.

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Algorithm (GVF)

• Edge map f (x,y) from Image
• Gradient vector flow field
• That minimizes energy function
• GVF can be found by solving Euler equation as a
  function of time

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Algorithm (GVF Snake)

• Parametric curve solving

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Examples
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3D surfaces
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Validate

• Images in the authors website
• Images from the Intelligent Scissors Lab