[Insight-users] Measuring texture of objects
Nick Arini
nick.arini at amersham.com
Thu Jun 17 08:27:15 EDT 2004
Zachary,
thanks for an extremely comprehensive reply. I will work through your
suggestions and let you know how I get on.
Best regards,
Nick
Zachary Pincus <zpincus at stanford.edu>
Sent by: insight-users-bounces at itk.org
16/06/2004 19:52
To: "Nick Arini" <nick.arini at amersham.com>
cc: insight-users at itk.org
Subject: Re: [Insight-users] Measuring texture of objects
Nick,
If you want to perform spatial autocorrelations, probably the easiest
thing to do is to perform the operation in the fourier domain. The
basic idea is that the fourier transform of the autocorrelation image
is the component-wise modulus of the fourier transform of the original
image. So generate the fourier coefficients of an image, then mulitply
each coefficient by its complex conjugate, and perform the inverse
transform.
I think that the ITK FFT filters might work, or you could use a
different FFT package.
However, there are other texture measurements that might be useful,
too. I recently submitted a class
(itkScalarImageToGreyLevelCoocurrenceMatrixGenerator) that computes a
Grey Level Co-occurrence Matrix for an image. Hopefully it will show up
in the CVS soon. GLCM's are used frequently in texture analysis (see:
http://www.ucalgary.ca/~mhallbey/texture/texture_tutorial.html )
I plan in the near future to extend this class to work on masked images
-- currently it just works on entire requested regions. Additionally, I
hope to contribute a "texture coefficient calculator" class that will
calculate various texture parameters from an image, as described on the
above web page, and here:
http://www.cssip.uq.edu.au/meastex/www/algs/algs/algs.html )
That said, I don't yet have these methods written, so if you're in a
hurry, other methods might prove more useful. There's a lot of
information about texture (and everything else) here:
http://homepages.inf.ed.ac.uk/rbf/CVonline/ -- use the search.
Zach Pincus
Department of Biochemistry and Program in Biomedical Informatics
Stanford University School of Medicine
On Jun 16, 2004, at 8:17 AM, Nick Arini wrote:
>
> Dear ITK users,
>
> I would like to measure the texture (say spatial autocorrelation) of
> objects or regions (irregular in shape) defined by a segmentation.
>
> For example, say I have a 2D image which I binary threshold to give me
> a collection of region masks and I want the texture of each of these
> regions by measuring the spatial relationships of pixels in the
> original image which form a connected set defined by the region mask
> (I hope that was a clarification!).
>
> Can someone point me in the right direction with regard to ITK
> classes. I just need a kick start.
>
> Many thanks,
>
> Nick
>
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> Insight-users at itk.org
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