[ITK-users] Problem with itk::ImageToHistogramFilter

[Matt McCormick]

Hi Maximilian,

It is necessary to call

  imageToHistogramFilter->SetAutoMinimumMaximum( false );

 http://www.itk.org/Doxygen/html/classitk_1_1Statistics_1_1ImageToHistogramFilter.html#ab0f2c568bbb0ec3ff22e27e10b6af295

Usually, the range of values are computed from the input image.

HTH,
Matt

On Wed, Aug 27, 2014 at 8:29 AM, maximilian
<maximilian_oliver.mordig at roche.com> wrote:
> I am having problems with the itk::ImageToHistogramFilter.
>
> I am generating ellipses that I want to add to an image that already
> contains some ellipses (in each iteration step, I add one ellipse to an
> image being the result of previous iterations). To see if the new ellipse
> overlaps by more than (let's say) 10%, I use the ImageToHistogramFilter.
> The previous image has objects that all have pixel values of 1. The newly
> added ellipse has value of 2. So, to get the number of overlapping pixels, I
> add up both images and I count the number of pixels = 3 in that image.
>
> I set the histogram bin minimum to 0 (background) and the histogram bin
> maximum to 3 (+ some constant c) and the number of bins such that the step
> is = 1 (here, it is 3 + c). However, when I output the average frequencies
> associated to each bin, I get values between 0 and 2 (number like 1.92) and
> not between 0 and 3 + c (see output of program of attached file). Why?
>
> GenerateCells.cxx
> <http://itk-insight-users.2283740.n2.nabble.com/file/n7586128/GenerateCells.cxx>
>
>
>
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