[Insight-users] Segmented volume scaling problem, why its working with 2D and not with 3D?

[Juliette Deniau]

Hi Bill, 
Thank you very much for your answer.
I tried your code and it is working for my data, thanks. However, what is wrong in my code is not the size (I compute it as you did) but it’s in the statement code: 
resampler->SetOutputDirection ( reader->GetOutput()->GetDirection());
which I do not include in my code. Actually I do not set the direction of my resamopling filter(I have not find such thing elsewhere !).
I have another question regarding how you compute the output size. In your code you do the following:
outputSize[i] = static_cast<SizeValueType>(inputSize[i] * inputSpacing[i] / outputSpacing[i] + .5);
my question is why you add the 0.5 to the outputSpacing[i]? what I’m doing to compute the size is the follwing:
outputSize[i] = (inputSize[i] * inputSpacing[i] / outputSpacing[i]);
Regards 
Juliette

--- En date de : Mar 6.10.09, Bill Lorensen <bill.lorensen at gmail.com> a écrit :


De: Bill Lorensen <bill.lorensen at gmail.com>
Objet: Re: [Insight-users] Segmented volume scaling problem, why its working with 2D and not with 3D?
À: "Juliette Deniau" <juliette.deniau at yahoo.fr>
Cc: "luis ibanez" <luis.ibanez at kitware.com>, "insight" <insight-users at itk.org>
Date: Mardi 6 Octobre 2009, 16h08


I suspect that your size calculation is incorrect.

Attached is a program that will resample a meta volume. (Note it uses a LinearInterpolateImageFunction. You should change this to a nearest neighbor interpolator).

You can see how I calculate the size.

Bill


On Tue, Oct 6, 2009 at 10:09 AM, Juliette Deniau <juliette.deniau at yahoo.fr> wrote:






Dear Luis and Itk users, 
I’m trying to scale a segmented volume (obtained by confidence connected filter)using itkAffineTransform but the result volume has information only in one slide. When I use the original volume instead of the segmented one, the results are fine. 
I applied the same code to  2D image ( segmented  image using confidence connected filter)and the original image, the results are fine for both of them. 
What I cannot understand is why  this is working for 2D original image, 2D segmented image, the original volume and not for the 3D segmented volume ? 
I attach both codes that I use for my test(2D and 3D cases) 
Thank you 
Juliette

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