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

[Sergio Vera]

Would the ridges of the Distance map  work as  good speed image?
Other than being close to 1 near the centerline. Perhaps the averagw
outward flux of the distance map (~= risges of the distance map) ,
normalized properly top 0-1 would do the trick.

On Mon, Apr 9, 2012 at 11:13 PM, Dan Mueller <dan.muel at gmail.com> wrote:

> Hi superZZ,
>
> Good to hear the approach is suitable for your needs.
>
> Cheers, Dan
>
> On 10 April 2012 03:01, jxdw_zlf <jxdw_zlf at yahoo.com.cn> wrote:
> > Dear Dan,
> >
> > Thank you! It works fine now. Really appreciate for your help :)
> >
> > Best Regards,
> >
> > superZZ
> >
> >
> > ------------------ Original ------------------
> > From:  "Dan Mueller"<dan.muel at gmail.com>;
> > Date:  Mon, Apr 9, 2012 08:41 PM
> > To:  "zlf"<jxdw_zlf at yahoo.com.cn>;
> > Cc:  "insight-users"<insight-users at itk.org>;
> > Subject:  Re: [Insight-users] Extract centerlines from a 3D segmented
> binary
> > image
> >
> > 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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-- 
Sergio Vera

 Alma IT Systems
 C/ Vilana, 4B, 4º 1ª
 08022 Barcelona
 T. (+34) 932 380 592
 www.alma3d.com
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