Posted by
Michael Schmid on
Jul 17, 2009; 12:42pm
URL: http://imagej.273.s1.nabble.com/longest-inscribed-lines-tp3690610p3690616.html
Hi Gabriel,
thank you for spending some time on this.
I have three problems with the skeleton:
(1) Short side branches, mainly due to the uneven width of the
grains. I could modify one of my plugins to get rid of these.
(2) Long side branches that are due to a long a grain. Not so easy to
disconnect such a side branch because one has to check which of the
three branches meeting in a point is the sidebranch, and which one
runs straight through.
(3) Related to (2): sometimes two grains with different orientation
touch at the ends, resulting one long line with a kink -
morphologically the same as a straight line.
Any ideas for this?
Concerning the 'wigglyness' - yes, this could be a problem for a
'longest inscribed lines' algorithm, but I think I could cope with it:
A dilation operation that does not join particles would solve it -
maybe with your morphology collection? Otherwise simple dilation and
resetting the skeletonized background would do it.
Michael
________________________________________________________________
On 17 Jul 2009, at 14:00, Gabriel Landini wrote:
> On Friday 17 July 2009 12:56:36 Michael Schmid wrote:
>> Hi everyone,
>>
>> maybe someone of you has a solution for the following problem:
>> I have images of elongated martensitic grains, e.g.:
>>
http://www.iap.tuwien.ac.at/~schmid/MartensiticGrains.png>>
>> I want to get some indication of the lengths of the grains to compare
>> it with other images.
>> The Fourier transform is dominated by the grain widths, so it does
>> not help.
>> Often, the grains are not separated but touch others, so caliper
>> length (Feret's diameter) won't work either.
>>
>> A possibility would be searching for the "longest inscribed lines",
>> i.e., the longest straight lines that fit into the foreground of the
>> image, or even better, the longest line with a limited curvature (to
>> follow slightly curved grains). Does anyone know about a plugin or
>> some other transform/method that could do this?
>
> With wiggly objects like this it is possible that the inscribed
> lines might
> end being quite short.
> I would take the skeleton of the crystals, then run the
> connectivity plugin
> and threshold between 1 and 3. This would break the linear parts of
> the
> skeleton. I would use the Lines8 plugin to get their length
> distribution.
>
> I hope it helps
>
> Gabriel