A finite element method applied to new active contour models and 3D reconstruction from cross sections
Résumé
The use of energy-minimizing curves, known as "snakes" to extract features of interest in images has been introduced by Kass, Witkin & Terzopoulos. We present a model of deformation which solves some of the problems encountered with the original method such as instability and initial data while reducing the computational complexity. This model makes the curve behave like a balloon which is inflated by an additional force. The initial curve need no longer be close to the solution to converge. The external forces, that push the curve to the edges, are modified to give more stable results. The system is solved using a conform finite element method in the minimization process. The evolution to the equilibrium presents less oscillations, convergence obtained faster and the final results are more accurate. We have applied this model for segmenting ultrasound and magnetic resonance images. We have also made a first stage to 3D object reconstruction, by tracking the extracted contour on a series of successive cross sections.