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Application of Gradient Vector Flow (GVF) Active Contour in Searching Heart Surface

Application of Gradient Vector Flow (GVF) Active Contour in Searching Heart Surface. Chunlei Han Turku PET centre March 31, 2005. Contains. Active Contour Gradient Vector Flow (GVF) Results and Demonstration. Active Contour Models. Names: Snake, Active Contour, Deformable Model

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Application of Gradient Vector Flow (GVF) Active Contour in Searching Heart Surface

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  1. Application of Gradient Vector Flow (GVF) Active Contour in Searching Heart Surface Chunlei Han Turku PET centre March 31, 2005

  2. Contains • Active Contour • Gradient Vector Flow (GVF) • Results and Demonstration

  3. Active Contour Models Names:Snake, Active Contour, Deformable Model First introduced in 1987 by Kass et al, and gained popularity since then. Kass et al: Snakes: active contour models. International Journal of Computer Vision, 321-331, 1987 The contour is atracted to image boundares controlled by two forces (energies) Internal force (itself) external force (image) Initial line target

  4. Definition of active contour energy A contour is definded as a parameter curve Internal energy External energy is defined based o image information, such image intensity, edge ect.

  5. Internal energy Elastic Energy is treated as an elastic rubber band possessing elastic potential energy. Responsible for shrinking of the contour Rigid Energy is considered to behave like a thin metal strip giving rise to bending energy. Bending energy is minimum for a circle.

  6. Solution of Active Contour (Snake)

  7. External energy Xu & Price: Snakes, Shape and Gradient Vector Flow. Processing Image on Transactions IEEE 1998, March, 359-369

  8. Gradient Vector Flow (GVF) Why need GVF The original active contour can not move in many cases, such as • concavities • initial line is far away from object • initial line acrosses with object (has points inside and outside of object)

  9. GVF field is defined as the equilibrium solution to the following diffusion equation Xu & Prince: Snake, shape and gradient vector flow. IEEE trans image processing 1998, 7:359-369

  10. Result and Demostration

  11. Conclusion GVF active contour is a useful method in heart surface searching

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