[Insight-users] Fast Marching Filter produces blank output

[Dan Mueller]

On 28/09/2007, Charlotte Curtis <curtisc at uoguelph.ca> wrote:
> I'm using ITK filters through MeVisLab, it comes with nearly all of them
> implemented as modules.

Okay.

> It was my understanding that the stopping value should be somewhere around
> the values of the voxels at the edge of the region, which for me is
> somewhere between 200 and 1000 HU.  I've tried using very large numbers, but
> I still get nothing output.

The stopping value has nothing to do with the intensity range of the
input image -- it tells the algorithm at what *arrival value* the
processing should stop. If you are not sure, make the value large or
use the default (which will force the algorithm to take longer to
execute, but guarantee you a result).

> I posted a screenshot from the program showing (left to right): the input
> image, the FastMarching dialogue box, and the speed image.  It can be found
> at http://www.uoguelph.ca/~curtisc/MeVisScreenshot.png.

Unfortunately a screenshot doesn't help very much. It is best to
inspect the raw data (especially the speed function to ensure it is in
the correct range). Can you temporarily save the speed function you
are using and post this? Also, the initial trial seed/region would be
helpful.

Cheers, Dan