[Insight-users] Contour of an image (with Anisotropic Diffusion Filtering)

[Luis Ibanez]

Hi Daniel,

The AnisotropicDiffusionImageFilter should have already
smoothed the homogeneous regions of your image without
degrading the interfaces between regions.

The application of any of the edge-detection filters will
probably extract a good set of contours from the smoothed
image.

You may want to try any of the following filters:

Canny
http://www.itk.org/Insight/Doxygen/html/classitk_1_1CannyEdgeDetectionImageFilter.html

Sobel
http://www.itk.org/Insight/Doxygen/html/classitk_1_1SobelEdgeDetectionImageFilter.html

Gradient Magnitude
http://www.itk.org/Insight/Doxygen/html/classitk_1_1GradientMagnitudeImageFilter.html

Please note that these filters require the images to use "float"
as pixel type. You may use the itkCastImageFilter to convert from
other types. (Although the output of the AnisotropicDiffussion filter 
should already be of "float" type).

Also, note that Canny and Sobel produce an output with gray levels 
normalized in the range [0:1].  If you want to convert their output to
an image type of integer pixels type it will be necessary to rescale
the gray levels.

The following filters could be useful for this purpouse:

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

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



Please let us know if you encounter any difficulting extraction
the contours.

Thanks


   Luis


===================================================

Daniel Mora wrote:
> Hello,
> 
> I'd like to know if there's any way to obtain the contour of an image 
> after aplying an Anisotropic Diffusion Filter. That is, if it's posible 
> to recover the information that retains only the contour as well. The 
> class that I use to enhance the contours is 
> AnisotropicDiffusionImageFilter. Thanks a lot;
> 
> Daniel Mora
> 
> ENSTB-LATIM
> 
> 
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