Would the ridges of the Distance map work as good speed image?<div>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.<br>
<br><div class="gmail_quote">On Mon, Apr 9, 2012 at 11:13 PM, Dan Mueller <span dir="ltr"><<a href="mailto:dan.muel@gmail.com">dan.muel@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi superZZ,<br>
<br>
Good to hear the approach is suitable for your needs.<br>
<br>
Cheers, Dan<br>
<br>
On 10 April 2012 03:01, jxdw_zlf <<a href="mailto:jxdw_zlf@yahoo.com.cn">jxdw_zlf@yahoo.com.cn</a>> wrote:<br>
> Dear Dan,<br>
><br>
> Thank you! It works fine now. Really appreciate for your help :)<br>
><br>
> Best Regards,<br>
><br>
> superZZ<br>
><br>
><br>
> ------------------ Original ------------------<br>
> From: "Dan Mueller"<<a href="mailto:dan.muel@gmail.com">dan.muel@gmail.com</a>>;<br>
> Date: Mon, Apr 9, 2012 08:41 PM<br>
> To: "zlf"<<a href="mailto:jxdw_zlf@yahoo.com.cn">jxdw_zlf@yahoo.com.cn</a>>;<br>
> Cc: "insight-users"<<a href="mailto:insight-users@itk.org">insight-users@itk.org</a>>;<br>
> Subject: Re: [Insight-users] Extract centerlines from a 3D segmented binary<br>
> image<br>
><br>
<div class="HOEnZb"><div class="h5">> Hi superZZ,<br>
><br>
> To reiterate my first email: this method is a little tricky due to the<br>
> need for a _good_ speed function. A good speed function has high<br>
> values (~1.0) near the centerline and low values (0.0) away from the<br>
> centerline.<br>
><br>
> A distance map can be used generate such a speed function, but the<br>
> output of the distance map is _NOT_ the speed function: the distance<br>
> map requires further processing!<br>
><br>
> Here are the steps I used to quickly generate a speed function<br>
> (commands are in SharpImage syntax, a custom prototyping environment<br>
> of mine, but you should be able to work out what is happening):<br>
><br>
> SignedMaurerDistance<br>
> SmoothingRecursiveGaussian Sigma=1.0<br>
> Threshold Lower=-10 Upper=100 OutsideValue=-10<br>
> RescaleIntensityToF OutputMinimum=0.0 OutputMaximum=1.0<br>
> UnaryPixelMath Operation="Power" Exponent=3<br>
><br>
> The results look acceptable to me (see attached).<br>
><br>
> HTH<br>
><br>
> Cheers, Dan<br>
><br>
> On 9 April 2012 16:26, zlf <<a href="mailto:jxdw_zlf@yahoo.com.cn">jxdw_zlf@yahoo.com.cn</a>> wrote:<br>
>> Dear Dan,<br>
>><br>
>> I process airway.mhd with SignedMaurerDistanceMapImageFilter. Pass<br>
>> SignedMaurerDistanceMapImageFilter's result as speed image. The result is<br>
>> even worse.<br>
>><br>
>><br>
>> <a href="http://itk-insight-users.2283740.n2.nabble.com/file/n7449026/centerline_SignedMaurerDistanceMapImageFilter.jpg" target="_blank">http://itk-insight-users.2283740.n2.nabble.com/file/n7449026/centerline_SignedMaurerDistanceMapImageFilter.jpg</a><br>
>><br>
>> Regards,<br>
>><br>
>> superZZ<br>
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