diff --git a/Modules/DiffusionImaging/DiffusionCore/Algorithms/itkProjectionFilter.h b/Modules/DiffusionImaging/DiffusionCore/Algorithms/itkProjectionFilter.h
index f83a27f20e..163bf99444 100644
--- a/Modules/DiffusionImaging/DiffusionCore/Algorithms/itkProjectionFilter.h
+++ b/Modules/DiffusionImaging/DiffusionCore/Algorithms/itkProjectionFilter.h
@@ -1,125 +1,155 @@
 /*===================================================================
 
 The Medical Imaging Interaction Toolkit (MITK)
 
 Copyright (c) German Cancer Research Center,
 Division of Medical and Biological Informatics.
 All rights reserved.
 
 This software is distributed WITHOUT ANY WARRANTY; without
 even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.
 
 See LICENSE.txt or http://www.mitk.org for details.
 
 ===================================================================*/
 
 #ifndef ITKPROJECTIONFILTER_H_
 #define ITKPROJECTIONFILTER_H_
 
 #include "itkObject.h"
 #include "itkImage.h"
 #include "mitkImage.h"
 #include "mitkTbssImage.h"
 
 namespace itk
 {
-class ProjectionFilter : public Object
-{
-  /*!
-  \brief itkProjectionFilter
-
-  \brief Performs the Projection Step of the TBSS algorithm from Smith et al. 2006.
 
 
+/**
+  * \brief Projection part of the TBSS pipeline
+  *
+  * This class performs the projection step of the TBSS pipeline
+  * (see Smith et al., 2009. http://dx.doi.org/10.1016/j.neuroimage.2006.02.024 )
+  * As input it takes a binary skeleton, a distance map, and a vector image containing the image gradients
+  * that are typically provided by the itkSkeletonizationFilter and the itkDistanceMapFilter.
   */
 
+
+class ProjectionFilter : public Object
+{
+
 public:
 
   typedef itk::Image<float, 3> RealImageType;
 
   typedef itk::CovariantVector<int,3> VectorType;
 
   typedef itk::Image<VectorType, 3> VectorImageType;
 
   typedef itk::Image<char,3> CharImageType;
 
   typedef itk::Image<float, 4> Float4DImageType;
   typedef itk::Image<float, 3> FloatImageType;
 
- // typedef itk::VectorImageType<float, 3> SubjectVolumesType;
 
 
 public:
 
   /** */
   typedef ProjectionFilter Self;
 
   /** Superclass */
   typedef Object Superclass;
 
   /** Smart Pointer */
   typedef SmartPointer<Self> Pointer;
 
   /** Smart Pointer */
   typedef SmartPointer<const Self> ConstPointer;
 
   /** */
   itkNewMacro( Self)
 
-  /** Generate Data. The image will be divided into a number of pieces, a number of threads
-  will be spawned and Threaded GenerateData() will be called in each thread. */
+
+  /** \brief Does the actual projection */
   void Project();
 
+
+  /** \brief Set the distance map
+   *
+   * Sets the distance map that decodes for every voxel the distance to the nearest point on the skeleton.
+   */
   itkSetMacro(DistanceMap, RealImageType::Pointer)
 
+
+  /** \brief Set the directions
+   *
+   * Sets the direction calculated by the TBSS skeletonization algorithm in itkSkeletonizationFilter.
+   */
   itkSetMacro(Directions, VectorImageType::Pointer)
 
+
+  /** \brief Set the binary skeleton
+   *
+   * Sets the binary skeleton that defines on which voxels must be projected.
+   */
   itkSetMacro(Skeleton, CharImageType::Pointer)
 
+
+  /** \brief Set the mask defining tubular structures on the skeleton
+   *
+   * Sets a binary mask that defines wich part of the white matter skeleton are tubular instead of sheet like.
+   * This is important because the a different projection method is used for sheet like structues and
+   * tubular structures.
+   */
   itkSetMacro(Tube, CharImageType::Pointer)
 
+
+  /** \brief Set a 4D image containing the 3D registered FA maps of all study subjects. */
   itkSetMacro(AllFA, Float4DImageType::Pointer)
 
+
+  /** \brief Returns a 4D image containing the skeleton projections of all subjects */
   itkGetMacro(Projections, Float4DImageType::Pointer)
 
 
 protected:
 
   /** Constructor */
   ProjectionFilter();
 
   /** Destructor */
   virtual ~ProjectionFilter();
 
   RealImageType::Pointer m_DistanceMap;
 
   VectorImageType::Pointer m_Directions;
 
   CharImageType::Pointer m_Skeleton;
 
   CharImageType::Pointer m_Tube;
 
   Float4DImageType::Pointer m_Projections;
 
   Float4DImageType::Pointer m_AllFA;
 
   int round(float x)
   {
     if (x>0.0) return ((int) (x+0.5));
     else       return ((int) (x-0.5));
   }
 
 protected:
 
 
 
 };
 
 }
 
 #ifndef ITK_MANUAL_INSTANTIATION
 #include "itkProjectionFilter.txx"
 #endif
 
 #endif