[Insight-users] Inversion of pixel value within a fixed intensity window

[Luis Ibanez]

Hi Amitesh,

Yes, you can use the IntensityWindowingImageFilter for this purpose.
http://www.itk.org/Insight/Doxygen/html/classitk_1_1IntensityWindowingImageFilter.html


a typical 8bit image can be inverted with this filter
by setting the following parameters:


   filter->SetInputMaximum( 255 );
   filter->SetInputMinimum(   0 );

   filter->SetOutputMaximum(   0 );
   filter->SetOutputMinimum( 255 );



For a description of filters that change intensity pixel-wise,
please look at the ITK Software Guide

    http://www.itk.org/ItkSoftwareGuide.pdf


Section 6.2.1, pdf-page 146.

----------------------------

You may want to look also at the following filters:

1) ShiftScaleImageFilter
http://www.itk.org/Insight/Doxygen/html/classitk_1_1ShiftScaleImageFilter.html

2) RescaleIntensityImageFilter
http://www.itk.org/Insight/Doxygen/html/classitk_1_1RescaleIntensityImageFilter.html

3) and if you are ok with non-linear transformations,
The Sigmoid image filter is commonly used for inverting images
when creating the spped image for LevelSets
http://www.itk.org/Insight/Doxygen/html/classitk_1_1SigmoidImageFilter.html


You may also look at the ImageAdaptors chapter in the
ITK Software Guide

   http://www.itk.org/ItkSoftwareGuide.pdf

Image adaptors are a good way of implementing Pixel-wise operations
and avoid the memory duplications that results from the use of
image filters.




      Regards,



          Luis



------------------------
Amitesh Agarwal wrote:

> Hello,
> 
> I wanted to know if there is any method available which can let me
> perform a mathematical operation on each pixel of a 3D .vtk image.
> 
> the function would be of type
> G(I) = -1* f(I) + (Imax - Imin) .... where I is the intensity value of
> a pixel, Imax is the intensity maxima in an image and Imin is the
> intensity minima in a image.
> 
> The reason for this pixel intensity transformation is that I wanted to
> create a negative of an Image or in other words I wanted to invert the
> intensity value within a maximum-minimum intensity range.
> 
> Thanks
> 
> Amitesh
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> 
>