[Insight-users] enhancing plate like structures (by modifying itkHessianSmoothed3DToVesselnessMeasureImageFilter)

[Dr. Roman Grothausmann]

Dear mailing list members, dear Luca,


Recently I was trying to enhance vascular structures from airways with 
the vessel enhancement filters from ITK (objectness and vessel 
enhancement). The  problem is that these vessels are not filled in the 
tomograms our imaging technique yields. Only the airway walls are 
imaged, which corresponds to an uneven 2D surface. Since it is only a 3D 
not an ND problem, I tried to modify 
itkHessianSmoothed3DToVesselnessMeasureImageFilter to enhance not 
vessels (1D) structures but plates/walls. Therefore I exchanged lambda 1 
and 3 in the weighting function. Sadly, I could not get the filter  to 
enhance the airway walls.
Have I missed anything or would enhancing plateness this way only work 
for not-curved planes?


Here the important part of the diff of my changes:

diff -au 
itk/IJ-Vessel_Enhancement_Diffusion.1/itkHessianSmoothed3DToVesselnessMeasureImageFilter.txx 
itk/plateness3D_01/itkHessianSmoothed3DToPlatenessMeasureImageFilter.txx



+      ////swap Lambda1 and Lambda3 to enhance "plateness"
+      double swap_tmp= Lambda1;
+      Lambda3= Lambda1;
+      Lambda1= swap_tmp;
+      ///swapping done
+
        double Lambda1Abs = vnl_math_abs( Lambda1 );
        double Lambda2Abs = vnl_math_abs( Lambda2 );
        double Lambda3Abs = vnl_math_abs( Lambda3 );
@@ -162,14 +168,13 @@
        double vesMeasure_3  =
           ( 1 - vcl_exp( -1.0 * (( vnl_math_sqr( S )) / ( 2.0 * ( 
GammaSqr)))));

-      double vesMeasure_4  =
-         vcl_exp ( -1.0 * ( 2.0 * vnl_math_sqr( m_C )) /
-                                   ( Lambda2Abs * (Lambda3Sqr)));
+      double vesMeasure_4  = 1; ////plateness for now not smoothed
+      //double vesMeasure_4  = vcl_exp ( -1.0 * ( 2.0 * vnl_math_sqr( 
m_C )) / ( Lambda2Abs * (Lambda3Sqr))); ////check if this makes sense 
for plateness


Many thanks for any help or hints.
Roman

-- 
Dr. Roman Grothausmann

Tomographie und Digitale Bildverarbeitung
Tomography and Digital Image Analysis

Institut für Funktionelle und Angewandte Anatomie, OE 4120
Medizinische Hochschule Hannover
Carl-Neuberg-Str. 1
30625 Hannover

Tel. +49 511 532-9574