Segmentation and visualization of blood vessels obtained by 3D rotational angiography
Laurent Vieira de Mello
Micro-engineering
Student Project
Semester Project, February 2002
The meaning of NLD filtering (Non-Linear Diffusion) is to compute the input image with a gaussian kernel. Its length is given by the sigma parameter. The algorithm processes with a large gaussian kernel when we consider the background of the image, but it inhibits the filtering when it is about the edges, in order to keep important details of the image. Lambda is a contrast parameter that depends on the image contrast. The best way to find a good value for it is to try different ones!
EED filtering (Edge-Enhancing anisotropic Diffussion) is a different algorithm that filters the image by taking the edges orientation into account and thus keeps the edges more linear.
Demo Applet : http://bigwww.epfl.ch/demo/jnonlinearfiltering/index.html
 |
 |
 |
| Original Image | NLD filtering | EED Filterting |