Posted by
Philippe Grosjean on
Nov 27, 2005; 7:22am
URL: http://imagej.273.s1.nabble.com/particle-analysis-Feret-diameter-tp3704371p3704372.html
Hi all,
If my understanding of Feret diameter in ImageJ is correct, this is the
*maximum* one, calculated at various angles. But how many angles are
considered? I browse the source code rapidly, and found several
getFeretsDiameter() functions (ij.gui.OvalRoi, PolygonRoi, Roi &
ShapeRoi). In particular, in ShapeRoi, you also have a getMinFeret()
function, but it is commented out. Apparently, shape is rotated every
degree in these function?
Anyway, I join Mr Kachrimanis in a request for reporting also the
*minimum* (and possibly the *mean*) Feret diameter. A lot of derived
measurements can be done if you have those additional measurements. My
plan for the future is to patch ImageJ to report those. This should not
be too difficult... unfortunatelly, I am not a Java programmer and have
little free time now. So, this is a pain for me, and I will not do it
before one year, or so (I still hope to see it added in a future version
of ImageJ).
Best,
Philippe Grosjean
P.S.: by the way, many thanks for adding 'Skew' and 'Kurt' in the
particle analyzer in the latest version of ImageJ!
..............................................<°}))><........
) ) ) ) )
( ( ( ( ( Prof. Philippe Grosjean
) ) ) ) )
( ( ( ( ( Numerical Ecology of Aquatic Systems
) ) ) ) ) Mons-Hainaut University, Pentagone (3D08)
( ( ( ( ( Academie Universitaire Wallonie-Bruxelles
) ) ) ) ) 8, av du Champ de Mars, 7000 Mons, Belgium
( ( ( ( (
) ) ) ) ) phone: + 32.65.37.34.97, fax: + 32.65.37.30.54
( ( ( ( ( email:
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..............................................................
K. Kachrimanis wrote:
> Dear all,
>
> I have a question or rather a feature request related to the particle analysis, which so far has limited functionality copared to commercial software packages in regard to particle size and shape analysis. I have noticed that there is a Feret diameter included in the module, but it is not clear at which orientation is this Feret measured. Since Feret diameters depend on particle orientation, a Feret at a single orientation is virtually useless, particularly when one has to deal with elongated particles. Would it be possible to include more Ferets, at different angles, and also add an automatic selection of maximum and minimum Ferets? This would enable the calculation of the aspect ratio and other relevant shape descriptors.
>
> Regards,
>
> K.Kachrimanis.
>
>