[vtkusers] vtkImageAnisotropicDiffusion3D Noise problem

[Simon ESNEAULT]

Hi all,

There is a strange behavior with the vtkImageAnisotropicDiffusion3D applied
on an unsigned char volume. The computation of the diffusion is done with a
double precision, and at the end of the process, the whole image is casted
to the original format using vtkImageData CopyAndCastFrom(..) . But some
value are greater than 255 (or lower than 0) and the cast gives some wrong
values. For Exemple a value of 300 in double gives a 44 uchar.

And the result is a noisy image which is not so good for a smooth filter ...
Maybe before to be casted, all the scalars should be scaled into a correct
window [0,255] for unsigned char, etc ...

Can someone do something for 2 /* lazy-coders */  french students :o)

We've tried to but we don't know how to manage it with a threaded method
(min and max could be different on each thread, no ?)

Thanks for your help

Simon

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Simon Esneault
Laboratoire Traitement du Signal et de l'Image, (LTSI, UMR-INSERM 642)
Université de Rennes I, Campus de Beaulieu,
35042 Rennes Cedex, France.
Tel : +33 (0)6 64 61 30 94
Mail : simon.esneault at univ-rennes1.fr
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