Re: smoothness

Posted by Mauro Maiorca on Dec 05, 2013; 11:41am
URL: http://imagej.273.s1.nabble.com/smoothness-tp5005806p5005820.html

Hi Rita,

if A is your image, and s(A) is your image smoothed, you might want
to analyse |A-s(A)|. An easy way is to measure the variance of |A-s(A)|:
the higher variance, the more the raggedness. Also, you might want to play
around with the "smoothing" function s. Gaussian smoothing is isotropic,
thus var|A-s(A)| will also weight irregularity of the edges. In case you
are not interested in edges' irregularities, you can use an inhomogeneous
and/or anisotropic diffusion filter [1], for example the Perona-Malik has
the property of smoothing preserving edges and coherence enhancing
diffusion works well with fingerprint-like features, as a smoothing
function s you might also want to try a "total variation" approach [2].

cheers,
Mauro

[1] http://rsbweb.nih.gov/ij/plugins/anisotropic-diffusion.html
[2] http://fiji.sc/javadoc/fiji/denoise/ROF_Denoise.html


On Thu, Dec 5, 2013 at 4:45 AM, Rita Castilho <[hidden email]> wrote:

> Dear Image J users
> I need to measure the smoothness (or the opposite, raggedness) of a
> surface. It is an island, but I guess it could be any surface really. Is
> there a way to measure this using Image J?
>
> Thanks for any help or pointers you can give me!
>
> Rita
>
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> RITA CASTILHO
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