Re: The definiation and measurement of the curvature of porosities in Material science

Posted by Xiaoxiong Xing on Dec 05, 2013; 7:33pm
URL: http://imagej.273.s1.nabble.com/The-definiation-and-measurement-of-the-curvature-of-porosities-in-Material-science-tp5005814p5005827.html

Thanks, Jim.

I now have an image stack taken by phase-contrast tomography. I read
the "Surface
Curvature from Range Images", it assumes a surface defined as a function of
two coordinates.

Do you know ff there is a plugin that can fit triangle mesh for the
porosities and can export the mesh data, so that I can do the curvature
calculation offline?

Thanks,
Xiaoxiong


2013/12/5 Jim Passmore <[hidden email]>

> Xiaoxiong,
> I'm afraid it may be difficult to give much of a definition of curvature,
> without some more details. You may for example be referring to the outline
> of a pore, or perhaps the curvature of the depression (sounds as if this is
> the more likely question). You don't say where you are in the process, but
> the first step is to get some sort of image that can be measured.  There
> are 2 types that immediately come to mind.
> * Cross section.  May be difficult if the particles are small and
> especially if you are interested in the depression.
> * Height map.  Can be acquired via a few different methods (not necessarily
> an exhaustive list):
>     * Confocal microscope
>     * Interference microscope (e.g., Scanning White Light Interference)
>     * Atomic Force Microscope
>     * Optical or Electron Microscope images taken at different angles, and
> using "stereoscopic" transformations to calculate the height map.
>
> Once you have some data, there are different ways to characterize the
> curvature.  You could simply fit a cross section to a circle, and report
> the "radius of curvature", or you could move up in complexity.
> Coincidentally, there was a recent discussion on another list, with the
> subject "Surface Curvature from Range Images (or Depth Maps)" [1].
>
> Hope this gets you started.
>
> Jim
>
> [1] https://groups.google.com/d/topic/scikit-image/PWdHI-Jy3rA/discussion
>
>
>
>
> On Wed, Dec 4, 2013 at 7:06 PM, Xiaoxiong Xing <[hidden email]
> >wrote:
>
> > Dear ImageJ users,
> >
> > I come from the field of Computer Graphics, not quit familiar with
> Material
> > science. I was asked to measure the curvature of irregularly shaped
> > porosities in a particle. Could anyone tell me the definition of
> curvature
> > in this context, and how I can calculate it?
> >
> > Thanks in advance
> >
> > Xiaoxiong
> >
> > --
> > ImageJ mailing list: http://imagej.nih.gov/ij/list.html
> >
>
>
>
>
> *-- Jim Passmore*
> Research Associate
> Sealed Air Corporation
>
> --
> ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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