[vtkusers] Re: Histogram Equalization

[Renaud Isabelle]

Hi,
 
I would like to use itkAdaptiveHistogramEqualizationImageFilter to compute a standard histogram equalization of my image.
 
After having read Stark's article, I understood that I have to set up my filter such as:
 
typedef itk::AdaptiveHistogramEqualizationImageFilter<WorkImageType> HistogramEqualizationType;
 
HistogramEqualizationType::Pointer histeqFilter = HistogramEqualizationType::New();
 
//provide minimum info
histeqFilter->GetOutput()->ReleaseDataFlagOn(); 
HistogramEqualizationType::ImageSizeType radius;
radius.Fill(0);
histeqFilter->SetRadius(radius);   
histeqFilter->SetAlpha(0);
histeqFilter->SetBeta(0); 

 
histeqFilter->SetInput(image_initiale);
rescaleFilter->SetInput(histeqFilter->GetOutput());
rescaleFilter->Update();
 
-- However, it seems that such a thing takes a real long time, and I don't know why. So did I miss something?
 
-- Moreover, my result, if any, is a dark image. so I am wondering if my input image (image_initiale) should be a rescaled image (gray values in [0 255])
 
Please help,
 
Isabelle
 
 
 
 
 
 

Glen Lehmann <glehmann at imaging.robarts.ca> a écrit :
Hey,

The best and most comprehensive itk and/or vtk example can be found 
here:

http://www.itk.org/Doxygen/html/ 
classitk_1_1AdaptiveHistogramEqualizationImageFilter.html

AHE's kinka tricky but J.A. Stark does a pretty good job of explaining 
it in the original paper.

HTH,
g

On Aug 2, 2005, at 4:09 PM, Peter G Carswell wrote:

> Renaud Isabelle wrote:
>
>> Hi guys,
>> I am wondering if ITK/VTK has already an implemented function whichs 
>> applies an histogram equalization on an image.
>> I read something on internet but didn't find nothing related to it.
>> Thanks in advance,
>> Isabelle
>>
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> Page 360 and Figure 10-8 mention Histogram Equalization, that is used 
> in "HistogramEqualization.tcl". I could not locate this file in my 
> distribution. Nor could I find, in the documentation, any mention of a 
> vtkImageHistogramEqualization object. It might be named something 
> else, but that would best be exhibited in "HistogramEqualization.tcl".
>
> pete
>
> -- 
> Peter G. Carswell The Ohio Supercomputer Center
> pete at osc.edu
> work: 614.292.1091 fax: 614.292.XXXX
> "DOC NOTE, I DISSENT. A FAST NEVER PREVENTS A FATNESS. I DIET ON COD."
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