[Insight-users] Edge Linking Problem

CSPL hyd2_affable at sancharnet.in
Mon, 22 Mar 2004 20:25:53 +0530


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Hello Zach Pincus,

 Thank you for that suggestion of yours, but I could not implement your =
suggestion.
 Firstly, I have already written the 8-connected code for the =
ConnectedComponentImage filter. For most of my needs just using the =
8-connected filter was sufficient, but surely there will be some case =
where this will fail.

 I tried to use the Geodesic Active Contour Filter, but could not get =
any result out of it. I could not find how to set the seed point for =
this filter. Even the example in ITK Software Guide does not use seed =
points.=20

 I could not understand what advection term and the components of the =
equation are.
Can you please explain to me why CannyEdgeDetection Filter fails to =
detect the edges of an object. For the same object, the gardient =
magnitude image filter is giving me better results.=20
=20
 Some times the canny filter is unable to identify even 25% of the =
entire trace (i.e., not even the top hemisphere of an elliptical =
object). There is a huge difference in intensities of the required =
object and its immediate background. It looks as if a white object is =
placed on a black background.=20

 Can I in some way use this information of "Why Canny fails?" rather =
than trying to improve its result by adding more filters to the =
application.

Regards,=20
Rama Krishna.

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<DIV><FONT face=3DArial size=3D2>Hello Zach Pincus,</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>&nbsp;Thank you for that suggestion of =
yours, but I=20
could not implement your suggestion.<BR>&nbsp;Firstly, I have already =
written=20
the 8-connected code for the ConnectedComponentImage filter. For most of =
my=20
needs just using the 8-connected filter was sufficient, but surely there =
will be=20
some case where this will fail.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>&nbsp;I tried to use the Geodesic =
Active Contour=20
Filter, but could not get any result out of it. I could not find how to =
set the=20
seed point for this filter. Even the example in ITK Software Guide does =
not use=20
seed points. </FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>&nbsp;I could not understand what =
advection term=20
and the components of the equation are.<BR>Can you please explain to me =
why=20
CannyEdgeDetection Filter fails to detect the edges of an object. For =
the same=20
object, the gardient magnitude image filter is giving me better results. =

<BR>&nbsp;<BR>&nbsp;Some times the canny filter is unable to identify =
even 25%=20
of the entire trace (i.e., not even the top hemisphere of an elliptical =
object).=20
There is a huge difference in intensities of the required object and its =

immediate background. It looks as if a white object is placed on a black =

background. </FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>&nbsp;Can I in some way use this =
information of=20
"Why Canny fails?" rather than trying to improve its result by adding =
more=20
filters to the application.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Regards, <BR>Rama=20
Krishna.</FONT></DIV></BODY></HTML>

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