[Insight-users] How to get rid of noise in image

[Luis Ibanez]

Hi Chunyan,


Noise reduction is discussed in detail in the SoftwareGuide:

    http://www.itk.org/ItkSoftwareGuide.pdf

Section 6.5, pdf-page 167 to 196.  You may want to look in
particular to section 6.5.2 "Edge Preserving Smoothing".

Just for the record, note that surprisingly the MedianImage
filter, when applied for multiple iterations produce results
similar to the anisotropic diffusion filter, but at a fraction
of the computational time.

Parameter fine tunning as always is an spiritual exercise
from which you cannot escape. Gather your patience, some
coffee and run systematic tests on your images by changing
the parameters of the filters.

You may find convenient to play with the demo application:

        InsightApplications/RegionGrowing

that offers you a user interface for several edge-preserving
smoothing filters.

    http://www.itk.org/HTML/RegionGrowingSegmentation.htm

you can simply use the first part of the application, where
the homogeneous image is generated.




   Regards,



      Luis


---------------
Jiang wrote:

> Dear ITK users,
> 
> Is there an efficient method to get rid of noise from image?
> 
> I want to extract edge from one image. And I use
> 
> itk::CannyEdgeDetectionImageFilter
> 
> It works fine. However, my image is very noisy, so the result of edge 
> extraction has many unwanted edge lines.
> 
> I try to use
> 
> Itk::GradientAnisotropicDiffusionImageFilter
> 
> to smooth the image, and set the parameters as follow:
> 
>          SmoothFilter->SetNumberOfIterations( 5 );
> 
>          SmoothFilter->SetTimeStep( 0.25 );
> 
>          SmoothFilter->SetConductanceParameter( 3.0f );
> 
> It works more or less, but not perfect.
> 
> Could some one tell me how to remove those noises in order to get 
> correct edge extraction result?
> 
>  
> 
>  
> 
> Thanks a lot!
> 
>  
> 
>  
> 
> Chunyan Jiang
>