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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Thank you Luis for your massage and patience!<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Sorry for my question, I'm just a student not an expert! But according to my reading in active contour and level set papers, I have found most of papers that are combining somehow level set with active contour which means that are not the same! <o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Any way what I would like to segment as object are weapon objects (knifes <SPAN style="mso-spacerun: yes"> </SPAN>and guns from data base of still images(2D)).<o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">These objects are usually small and thin in particular for the knife objects. I have already tested the region growing (Confidence connected filter), it gives acceptable results but it depends highly in the parameters, in particular the factor parameter.<o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Now I try to use level set and active contour based segmentation since they are more robust than the region growing methods. <o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Hope I have well explained my problem and hope I can get help and guidance from you. <o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Many thanks. <o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Regards</SPAN><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial"> <o:p></o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: Arial">Juliette<o:p></o:p></SPAN></P><BR></DIV>
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<B><SPAN style="FONT-WEIGHT: bold">De :</SPAN></B> Luis Ibanez <luis.ibanez@kitware.com><BR><B><SPAN style="FONT-WEIGHT: bold">À :</SPAN></B> Juliette Deniau <juliette.deniau@yahoo.fr><BR><B><SPAN style="FONT-WEIGHT: bold">Cc :</SPAN></B> insight-users@itk.org<BR><B><SPAN style="FONT-WEIGHT: bold">Envoyé le :</SPAN></B> Jeudi, 4 Décembre 2008, 19h46mn 27s<BR><B><SPAN style="FONT-WEIGHT: bold">Objet :</SPAN></B> Re: Re : [Insight-users] active contour, snake, deformable model and level set segmentation ???<BR></FONT><BR><BR>Hi Juliette,<BR><BR><BR>I'm not sure what you mean by:<BR><BR><BR> "Level set (purely level set without active contour)<BR> based segmentation?"<BR><BR><BR>The level set abstraction is implemented in such a way that at<BR>every pixel ITK solves an increment of a partial differential<BR>equation.<BR><BR><BR>The surface of the object happens to be defined at the loci<BR>where the level set image has zero
values.<BR><BR><BR><BR><BR>In practice, the distinction between a LevelSet and an Active<BR>Contours (or Snakes) is mostly of importance for those researchers<BR>who need to complete their annual quota of published papers and<BR>therefore are forced to be inventing "new" things every time, even<BR>when they are reincarnations of older ideas.<BR><BR><BR>In essence, the difference between LevelSets and Active contours<BR>is one of software implementation.<BR><BR><BR>If you need to solve a real and practical problem, we could<BR>advice you on what ITK methods to use.<BR><BR><BR>If you are in need of a flashy name for a segmentation method<BR>then... there is a lot out there to choose from. :-)<BR><BR><BR> Regards,<BR><BR><BR> Luis<BR><BR><BR>----------------------<BR>Juliette Deniau wrote:<BR>> Hi Luis,<BR>> <BR>> A one more question to clear completely my understanding.<BR>> <BR>> You said that “The
Level Set implementations of deformable models have all<BR>> the "LevelSet" string as part of their name” . Does this means that there is no<BR>> <BR>> level set (purely level set without active contour) based segmentation?<BR>> Thank you for your time<BR>> <BR>> Juliette <BR>> <BR>> <BR>> ------------------------------------------------------------------------<BR>> *De :* Luis Ibanez <<A href="mailto:luis.ibanez@kitware.com" ymailto="mailto:luis.ibanez@kitware.com">luis.ibanez@kitware.com</A>><BR>> *À :* Juliette Deniau <<A href="mailto:juliette.deniau@yahoo.fr" ymailto="mailto:juliette.deniau@yahoo.fr">juliette.deniau@yahoo.fr</A>><BR>> *Cc :* <A href="mailto:insight-users@itk.org" ymailto="mailto:insight-users@itk.org">insight-users@itk.org</A><BR>> *Envoyé le :* Mardi, 2 Décembre 2008, 21h04mn 06s<BR>> *Objet :* Re: [Insight-users] active contour, snake, deformable model and level set
segmentation ???<BR>> <BR>> <BR>> Hi Juliette,<BR>> <BR>> <BR>> Your observations are correct.<BR>> <BR>> If you are looking for a mesh-based implementation of a deformable model, then you should look at<BR>> <A href="http://www.itk.org/Insight/Doxygen/html/classitk_1_1DeformableSimplexMesh3DBalloonForceFilter.html" target=_blank>http://www.itk.org/Insight/Doxygen/html/classitk_1_1DeformableSimplexMesh3DBalloonForceFilter.html</A><BR>> <BR>> <BR>> and its example application in<BR>> <BR>> InsightApplications/DeformableModelSimplexMesh<BR>> <BR>> <BR>> This is closer to what is known as "Snakes" in the medical field.<BR>> <BR>> The Level Set implementations of deformable models have all<BR>> the "LevelSet" string as part of their name.<BR>> <BR>> <BR>> They will be:<BR>> <BR>> <BR>> $ find . -name "*LevelSetImageFilter.h"<BR>>
./itkAnisotropicFourthOrderLevelSetImageFilter..h<BR>> ./itkCannySegmentationLevelSetImageFilter.h<BR>> ./itkCurvesLevelSetImageFilter.h<BR>> ./itkGeodesicActiveContourLevelSetImageFilter.h<BR>> ./itkGeodesicActiveContourShapePriorLevelSetImageFilter.h<BR>> ./itkIsotropicFourthOrderLevelSetImageFilter.h<BR>> ./itkLaplacianSegmentationLevelSetImageFilter.h<BR>> ./itkNarrowBandCurvesLevelSetImageFilter.h<BR>> ./itkNarrowBandLevelSetImageFilter.h<BR>> ./itkNarrowBandThresholdSegmentationLevelSetImageFilter.h<BR>> ./itkSegmentationLevelSetImageFilter.h<BR>> ./itkShapeDetectionLevelSetImageFilter.h<BR>> ./itkShapePriorSegmentationLevelSetImageFilter.h<BR>> ./itkThresholdSegmentationLevelSetImageFilter.h<BR>> ./itkUnsharpMaskLevelSetImageFilter.h<BR>> ./itkVectorThresholdSegmentationLevelSetImageFilter.h<BR>> <BR>> <BR>> <BR>> Please let us know if you have further questions,<BR>> <BR>>
<BR>> Thanks<BR>> <BR>> <BR>> Luis<BR>> <BR>> <BR>> <BR>> ------------------------<BR>> Juliette Deniau wrote:<BR>> > Hi All,<BR>> ><BR>> > I’m confused about what type of segmentation methods are within itk, in particular the ones related to active contour and level set?<BR>> ><BR>> > In my understanding, active contour is the same as a deformable model and the same as a snake. The levelset segmentation is another type (use a PDE to evolve the curve).<BR>> ><BR>> > In itk there are some active contours implemented with the level set framework like the CurvesLevelSetImageFilter, I’m alright?<BR>> ><BR>> > Can any one tell me what are the segmentation filters which are purely active contour (snake) and those which use level set to evolve the curve? > Sorry if my question is
too stupid!<BR>> ><BR>> > Thanks a lot<BR>> ><BR>> > Juliette<BR>> ><BR>> ><BR>> ><BR>> > ------------------------------------------------------------------------<BR>> ><BR>> > _______________________________________________<BR>> > Insight-users mailing list<BR>> > <A href="mailto:Insight-users@itk.org" ymailto="mailto:Insight-users@itk.org">Insight-users@itk.org</A> <mailto:<A href="mailto:Insight-users@itk.org" ymailto="mailto:Insight-users@itk.org">Insight-users@itk.org</A>><BR>> > <A href="http://www.itk..org/mailman/listinfo/insight-users" target=_blank>http://www..itk..org/mailman/listinfo/insight-users</A> <<A href="http://www.itk.org/mailman/listinfo/insight-users" target=_blank>http://www.itk.org/mailman/listinfo/insight-users</A>><BR>> <BR></DIV></DIV></div><br>
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