http://imagej.273.s1.nabble.com/curvature-along-the-outline-of-a-thresholded-object-tp5023589p5023632.html
enclosed are two plots one with Thomas' the other one with your code. The
circles are the data. The line is a spline. With one little exception both
codes find the same number of locations with negative curvatures. Your code
between begin and end of the data file. Please note that this junction is
Am Mo., 6. Juli 2020 um 18:30 Uhr schrieb Herbie <
> Dear Bob and all others interested in this topic,
>
> meanwhile I've coded a little macro that appears working reasonably well.
>
> As expected, the interpolation is crucial and it turns out that a
> reasonable
> angle increment, i.e. number of local curvature values, for the sample
> images (450x450) provided by Thomas Fischer is about one degree or better
> less.
>
> My present interpolation strategy for the sample images is:
>
> //
> run( "Create Selection" );
> run( "Interpolate", "interval=4 smooth" );
> run( "Fit Spline" );
> run( "Interpolate", "interval=2 adjust" );
> //
>
> Finally I decided not to use polar coordinates but parametrized
> coordinates:
> <
>
https://en.wikipedia.org/wiki/Curvature#In_terms_of_a_general_parametrization> >
>
> For the sample image "0453.tif" I get 390 values.
> Attached please find the results table as a text file.
> Results_0453.txt
> <
http://imagej.1557.x6.nabble.com/file/t380516/Results_0453.txt>
>
> For comparison, I really should like to see the corresponding results of
> your approach.
>
> Regards
>
> Herbie
> :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
>
> Robert Dougherty wrote
> > Herbie,I have a post hoc processing step in my code. I smooth the
> > reciprocal of the radius of curvature. I actually use a weighted power
> > mean for that, as it seemed like the right thing to do, without much
> > evidence.Bob
> >
> >
> > Thomas,Thanks for the feedback and context. There are several things I
> > want to do with this, but I need to focus on my day job for a while.Bob
> >
> >
> > Sent from Smallbiz Yahoo Mail for iPhone
> >
> >
> > On Sunday, July 5, 2020, 10:14 AM, Thomas Fischer <
>
> > thmfischer@
>
> > > wrote:
> >
> > Dear Bob,
> >
> > My reply is late because I had computer problems. The result of the
> plugin
> > looks nice. In order to use it I would need two features
> > 1) A parameter to tune the sensitivity. Right now it is not sensitive
> > enough for my purpose. I am aware that an increase in sensitivity would
> > make the result more noisy. But as with the plugin of Thomas I would do
> > the
> > smoothing afterwards.
> > 2) A list of the curvature values along the circumference. Just looking
> at
> > the nice result is not enough in my case. I have to extract numbers from
> > this list.
> >
> > I am content with the plugin of Thomas. But as we say in German: the
> > better
> > is the enemy of the good.
> >
> > Best regards, Thomas
> >
> >
> >
> >
> >
> > Am So., 5. Juli 2020 um 07:33 Uhr schrieb Robert Dougherty <
>
> > rpd@
>
> > >:
> >
> >> Gabriel,
> >> Thanks. In case it matters, there is a new version with smoother
> >> calculation and a black background.
> >> Bob
> >>
> >> On Saturday, July 4, 2020, 11:33:56 AM PDT, Gabriel Landini <
> >>
>
> > g.landini@.ac
>
> >> wrote:
> >>
> >> Thanks Bob, I can confirm that it works fine.
> >> I think colourblind observers (red-green type) would see the green as
> >> some
> >> shades of yellow and blue as blue. At lease that is what the Dichromacy
> >> plugin
> >> shows.
> >> Regards
> >>
> >> Gabriel
> >>
> >>
> >> On Saturday, 4 July 2020 18:05:09 BST you wrote:
> >> > Gabriel,
> >> > In the meantime, I tried and failed to track down how ImageJ is
> >> supposed
> >> to
> >> > load the Phase LUT. Giving up, I changed the code to use another
> >> > sign-friendly LUT that I coded explicitly. Now Curvature displays the
> >> > results in green-blue. Going forward, it may be a question of which
> >> color
> >> > scheme is better. One could experiment by running the new version of
> >> > Curvature and then manually changing the LUT to Phase to simulate the
> >> old
> >> > version. Perhaps green-blue is better for colorblindness than the
> >> red-blue
> >> > scheme of Phase?
> >> >
> >> > Bob
> >>
> >> --
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http://imagej.nih.gov/ij/list.html> >>
> >>
> >> --
> >> ImageJ mailing list:
http://imagej.nih.gov/ij/list.html> >>
> >
> > --
> > ImageJ mailing list:
http://imagej.nih.gov/ij/list.html> >
> >
> >
> >
> > --
> > ImageJ mailing list:
http://imagej.nih.gov/ij/list.html>
>
>
>
>
> --
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