[Insight-users] Absolute Value Image

[Luis Ibanez]

Hi Glen,

An AbsImageFilter and AbsImageAdaptor have been
added to the toolkit. You may get them by using
the current CVS version.

Please let us know if you find any problem.


Thanks,


   Luis


--------------------
Glen Lehmann wrote
> Great! Thanks, Luis.
> I figured I'd end up doing this but I just wanted to be certain I wasn't 
> overlooking anything.
> 
> Thanks again for putting one together for me.
> 
> Glen
> 
> Luis Ibanez wrote:
> 
>> Hi Glen,
>>
>> Bad  news:  There is not an absolute value filter in ITK
>>
>> Good news:  You can write one in ten minutes.
>>             (7 minutes if you have good coffee at hand)
>>
>> Even better news: One is attached.
>>
>>
>> --------------------------------------------------------
>>
>> Simply take any of the filters deriving from the UnaryFunctorFilter
>> and replace the Functor with the "Abs()" function.
>> Take for example the "Sin" image filter
>>
>>     Insight/Code/BasicFilters/itkSinImageFilter.h
>>
>>
>> This will look like:
>>
>>
>> namespace Function {
>>
>> template< class TInput, class TOutput>
>> class Abs
>> {
>> public:
>>   Abs() {}
>>   ~Abs() {}
>>   inline TOutput operator()( const TInput & A )
>>   { return (TOutput)( ( A > 0 ) ? A : -A ); }
>> };
>> }
>>
>> Then use this functor for instantiating the filter.
>> This is shown in the attached file. Note that there
>> is only a header file, and that's all what is needed.
>> Here is where Generic Programming pays off.   :-)
>>
>>
>> ---------------------------------------------------------------------
>>
>>
>> Given that Abs is such a simple operation you may want
>> to use ImageAdaptors instead of ImageFilters.
>>
>> You will find details on who to write functional
>> ImageAdaptors in the SoftwareGuide
>>
>>    http://www . itk . org/ItkSoftwareGuide . pdf
>>
>> Please look at the ImageAdaptors chapter,
>> Chapter 12, pdf-page 522, paper-page 548.
>>
>> Functional adaptors are described in section 12.4
>> The example of this section is available in
>>
>>   Insight/Examples/DataRepresentation/Image/ImageAdaptor4.cxx
>>
>>
>> Please let us know if you run into any problem.
>>
>>
>>
>>    Thanks
>>
>>
>>
>>      Luis
>>
>>
>>
>>
>> ----------------------
>> Glen Lehmann wrote:
>>
>>> Hello,
>>>
>>> Here's an easy one;  Is there an ITK class to find that absolute 
>>> value of an image?
>>>
>>> i.e. in vtk I'd use vtkImageMathematics->SetOperationToAbsoluteValue.
>>>
>>> I didn't have any luck in the archives.
>>>
>>> Thanks,
>>> Glen
>>>
>> \
>>
>> ------------------------------------------------------------------------
>>
>> /*========================================================================= 
>>
>>
>>  Program:   Insight Segmentation & Registration Toolkit
>>  Module:    $RCSfile: itkAbsImageFilter.h,v $
>>  Language:  C++
>>  Date:      $Date: 2003/09/10 14:28:56 $
>>  Version:   $Revision: 1.16 $
>>
>>  Copyright (c) Insight Software Consortium. All rights reserved.
>>  See ITKCopyright.txt or http://www . itk . org/HTML/Copyright . htm for 
>> details.
>>
>>     This software is distributed WITHOUT ANY WARRANTY; without even 
>>     the implied warranty of MERCHANTABILITY or FITNESS FOR A 
>> PARTICULAR     PURPOSE.  See the above copyright notices for more 
>> information.
>>
>> =========================================================================*/ 
>>
>> #ifndef __itkAbsImageFilter_h
>> #define __itkAbsImageFilter_h
>>
>> #include "itkUnaryFunctorImageFilter.h"
>> #include "vnl/vnl_math.h"
>>
>> namespace itk
>> {
>>  
>> /** \class AbsImageFilter
>> * \brief Computes the ABS(x) pixel-wise
>> * * \ingroup IntensityImageFilters  Multithreaded
>> */
>> namespace Function {   
>> template< class TInput, class TOutput>
>> class Abs
>> {
>> public:
>>  Abs() {}
>>  ~Abs() {}
>>  inline TOutput operator()( const TInput & A )
>>  { return (TOutput)( ( A > 0 ) ? A : -A ); }
>> }; }
>>
>> template <class TInputImage, class TOutputImage>
>> class ITK_EXPORT AbsImageFilter :
>>    public
>> UnaryFunctorImageFilter<TInputImage,TOutputImage, 
>>                        Function::Abs<  typename 
>> TInputImage::PixelType,  typename TOutputImage::PixelType>   >
>> {
>> public:
>>  /** Standard class typedefs. */
>>  typedef AbsImageFilter  Self;
>>  typedef UnaryFunctorImageFilter<TInputImage,TOutputImage, 
>>                                  Function::Abs< typename 
>> TInputImage::PixelType, 
>>                                                 typename 
>> TOutputImage::PixelType> >  Superclass;
>>  typedef SmartPointer<Self>   Pointer;
>>  typedef SmartPointer<const Self>  ConstPointer;
>>
>>  /** Method for creation through the object factory. */
>>  itkNewMacro(Self);
>>  
>> protected:
>>  AbsImageFilter() {}
>>  virtual ~AbsImageFilter() {}
>>
>> private:
>>  AbsImageFilter(const Self&); //purposely not implemented
>>  void operator=(const Self&); //purposely not implemented
>>
>> };
>>
>> } // end namespace itk
>>
>>
>> #endif
>>  
>>
> 
> 
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