Posted by
Václav Šmilauer on
Mar 29, 2016; 12:41pm
URL: http://imagej.273.s1.nabble.com/Getting-started-with-grain-size-analysis-tp5016013p5016019.html
Hi Gabriel, thanks for suggestions.
> The image you posted has too many issues and I doubt that you would be able
> the analysis you want accurately without redesigning your setup.
>
> The first problem is the overlapping. You would do much better if your
> particles were on a single layer on a contrasted background. maybe you can get
> some surface with wells where each grain sits in one of those.That would also
> help with identifying the individual objects.
That is true, and I am aware that the current setup does not simplify
things. Unfortunately it is bulk material on conveyor with the flow in
the order of 100t/h. I will see what could be done.
> You should aim to reduce the uneven illumination. I would suggest that you try
> to resolve this issue before image capture, as doing it programatically tends
> to create new artefacts. Have you tried a light diffuser? or several light
> sources?
The light is ring-shaped LED strobe already diffused with
hemisphe-shaped matte white reflector/diffuser (thus all the light is
reflected). Will try larger diameter of the diffuser, this one is just
about 10cm.
> Also note that JPEG images are not good for imaging. They are lossy
> compressed, which add image artefacts which further interfere with the
> subsequent processing. Better save your data in TIFF or PNG formats. Saving a
> JPEG to TIFF to PNG does not resolve anything as the artifacts are already
> there.
It must have been imgur which serves the image as JPEG, normally it is
obtained uncompressed from GigE camera and stored as PNG.
Cheers, Vaclav
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