Anatomical structures segmentation

Deformable models are often use for segmentation. We illustrate the segmentation of the liver in abdominal CT-scan images. A geometric model of the liver is initialize inside the volumetric image and deformed toward image edges.

The segmentation process requires different stages:


(a) Initialization	(b) Rigid and affine registration

(c) Hybrid deformations (l low)	(d) Hybrid deformations (l high)

The liver template (a) is roughly initialized in the image and deformed toward edges. First it is registered (b), then it is deformed using the hybrid framework and iteratively increasing the locality (c)(d). As the model converges toward the patient liver's contour points, it is possible to release constraints (increase l) since the model is less outliers sensitive.

The following figure illusrtates the evolution of a model cut on one slice of the 3D image.


(a)	(b)

(c)	(d)

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