Introduction:

Dreams is a tool for performing non-rigid registration of images where tubular structure can be extracted from at least one image.

In this page, tubular structure means blood vessels, but can be generalize to tubes.

- Rigid Registration

-- Danielsson distance

- Physical Properties

Blood vessels can be describe by their physical properties.
We are interresting by the following:

1) Elasticity:
definition: Measure the elongation of vessels
depends on: ?

2) Rigidity:
definition: Measure the bending of tubes
depends on: the radius of the tube, the blood pressure inside the vessel, the type of vessels (complicated to define automatically in the human anatomy, could try manually).

4) Distance to the branch:
The basic implementation of snakes take care of this by starting from a fixed point, but maybe it is a good idea to had this property.

- Curve Parametrization

Some factors are guiding us for the choice of the parametrization:

The idea here is to use an arc-lenght parametrization with non-uniform sampling. In fact, the sampling is proportional to the radius.
Some avantages emerge when taking this parametrization:
1) The number of points to move (snake algorithm) is less than a regular sampling
2) This sampling takes care of the rigidity factor which should be proportional to the radius. This mean that we could use a constant measure for the rigidity by not including the radius in our equation. So we could use the angle between the two tangents as a ratio for curvature.

01/27/2003: Image Lunch Meeting, Computer Science: DeformableRegistrationJan03.ppt (movies.zip)

- Midas : Medical Image and Display Analysis System
- itkUNC : Add-on ITK classes

- Grass and Tree modeling in presence of wind. (link)