[Insight-users] Extract centerlines from a 3D segmented binary image

[Dan Mueller]

Hi superZZ,

To reiterate my first email: this method is a little tricky due to the
need for a _good_ speed function. A good speed function has high
values (~1.0) near the centerline and low values (0.0) away from the
centerline.

A distance map can be used generate such a speed function, but the
output of the distance map is _NOT_ the speed function: the distance
map requires further processing!

Here are the steps I used to quickly generate a speed function
(commands are in SharpImage syntax, a custom prototyping environment
of mine, but you should be able to work out what is happening):

SignedMaurerDistance
SmoothingRecursiveGaussian Sigma=1.0
Threshold Lower=-10 Upper=100 OutsideValue=-10
RescaleIntensityToF OutputMinimum=0.0 OutputMaximum=1.0
UnaryPixelMath Operation="Power" Exponent=3

The results look acceptable to me (see attached).

HTH

Cheers, Dan

On 9 April 2012 16:26, zlf <jxdw_zlf at yahoo.com.cn> wrote:
> Dear Dan,
>
> I process airway.mhd with SignedMaurerDistanceMapImageFilter. Pass
> SignedMaurerDistanceMapImageFilter's result as speed image. The result is
> even worse.
>
> http://itk-insight-users.2283740.n2.nabble.com/file/n7449026/centerline_SignedMaurerDistanceMapImageFilter.jpg
>
> Regards,
>
> superZZ
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