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itk::MRASlabIdentifier< TInputImage > Class Template Reference
identifies slab in MR images comparing minimum intensity averages
More...
#include <itkMRASlabIdentifier.h>
Inheritance diagram for itk::MRASlabIdentifier< TInputImage >:
[legend]Collaboration diagram for itk::MRASlabIdentifier< TInputImage >:
[legend]List of all members.
Detailed Description
template<class TInputImage>
class itk::MRASlabIdentifier< TInputImage >
identifies slab in MR images comparing minimum intensity averages
This class is templated over the type of image. In many cases, a 3D MR image is constructed by merging smaller 3D blocks (slabs) which were acquired with different settings such as magnetic settings and patient positions. Therefore, stripe like patterns with slabs can be present in the resulting image. Such artifacts are called "slab boundary" artifacts or "venetian blind" artifacts.
With the slab boundary artifacts in an image, even a same tissue class's intensity values might vary significantly along the borders of slabs. Such rough value changes are not appropriate for some image processing methods. For example, MRIBiasFieldCorrectionFilter assumes a smooth bias field. However, with the slab boundary artifacts, the bias field estimation scheme that MRIBiasFieldCorrectionFilter uses might not adopt well. So, the MRIBiasFieldCorrectionFilter creates regions for slabs using the MRASlabIdentifier and then apply its bias correction scheme to each slab.
For this identifier, a slice means 2D image data which is extracted from the input image along one of three axes (x, y, z). Users can specify the slicing axis using the SetSlicingDirection(int dimension) member. (0 - x, 1 - y, 2 - z).
The identification scheme used here is very simple. 1) Users should specify how many pixels per slice the identifier will sample. 2) For each slice, the identifier searches the specified number of pixels of which intensity values are greater than 0 and less than those of the other pixels in the slice 3) The identifier calculates the average for each slice and the overall average using the search results. 4) For each slice, it subtracts the overall average from the slice average. If the sign of the subtraction result changes, then it assumes that a slab ends and another slab begins.
Definition at line 65 of file itkMRASlabIdentifier.h.
Member Typedef Documentation
Constructor & Destructor Documentation
Member Function Documentation
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Compute the average values of miminum intensity pixels for each slice and compare the average values with overall averages. |
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Set/Get the minimum threshold value for the background pixels |
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template<class TInputImage> |
| virtual const char* itk::MRASlabIdentifier< TInputImage >::GetClassName |
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const [virtual] |
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Run-time type information (and related methods).
Reimplemented from itk::Object.
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template<class TInputImage> |
| virtual unsigned int itk::MRASlabIdentifier< TInputImage >::GetNumberOfSamples |
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const [virtual] |
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Set/Get the number of minimum intensity pixels per slice. |
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template<class TInputImage> |
| virtual int itk::MRASlabIdentifier< TInputImage >::GetSlicingDirection |
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const [virtual] |
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Set/Get the direction of slicing/ 0 - x axis, 1 - y axis, 2 - z axis |
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template<class TInputImage> |
| virtual double itk::MRASlabIdentifier< TInputImage >::GetTolerance |
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const [virtual] |
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Set/Get the tolerance value. |
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Method for creation through the object factory.
Reimplemented from itk::Object.
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template<class TInputImage> |
| void itk::MRASlabIdentifier< TInputImage >::PrintSelf |
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std::ostream & |
os, |
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Indent |
indent |
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const [protected, virtual] |
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Methods invoked by Print() to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.
Reimplemented from itk::Object.
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Set/Get the minimum threshold value for the background pixels |
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template<class TInputImage> |
| virtual void itk::MRASlabIdentifier< TInputImage >::SetNumberOfSamples |
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unsigned int |
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[virtual] |
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Set/Get the number of minimum intensity pixels per slice. |
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template<class TInputImage> |
| virtual void itk::MRASlabIdentifier< TInputImage >::SetSlicingDirection |
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int |
_arg |
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[virtual] |
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Set/Get the direction of slicing/ 0 - x axis, 1 - y axis, 2 - z axis |
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template<class TInputImage> |
| virtual void itk::MRASlabIdentifier< TInputImage >::SetTolerance |
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double |
_arg |
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[virtual] |
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Set/Get the tolerance value. |
The documentation for this class was generated from the following file:
Generated at Sun Apr 1 02:51:06 2007 for ITK by 
1.3.8 written by Dimitri van Heesch,
© 1997-2000