Hi Adam,
On 20.09.2012 9:43 PM, Adam Hughes wrote:
> I've been running analysis on images of gold nanoparticles on a surface. I
> noticed for very high coverages, the analyze particles routine goes a
> little bonkers. It tends to draw huge (relatively speaking) ellipses
> around large islands of particles, but then fills this large ellipse with
> several smaller ellipses. This means it is counting the same region
> multiple times.
The ellipses are "best fit" ellipses around the particles, that means
that not all the content of the ellipse necessarily belongs to the
particle in question. For large branched particles, the analysis draws
big ellipses.
Look at the respective section in the user guide for an explanation:
http://imagej.nih.gov/ij/docs/guide/146-30.html#toc-Subsection-30.2I suggest you use "Outlines" or "Bare Outlines" to see what's really
going on. If you want to detect single nanoparticles, try using
Process>Binary>Watershed on the thresholded image, or Process>Find
Maxima... on the original image.
Cheers,
Jan
>
> Check out these pictures to see what I
> mean.<
http://www.flickr.com/photos/87483089@N08/>
>
> Does anyone have any ideas of how I can change this behavior? I am using
> the default analyze particles algorithm, but heard there are several
> algorithms to analyze particles. Would any avoid this type of behavior?
> If not, are there workarounds?
>
> Thanks
>
> ~Adam
>
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