Major axis

[AJBell]

Is there a facility within ImageJ to automatically draw the major axis on
the ellipse that bounds an ROI?

If the image has been thresholded and ROI selected, the "measure" tool
will calculate the major and minor axis of the bounding ellipse, so it
must be possible to combine this with the draw function. I am however not
well versed enough to do it myself!

I want to do this to compare line profile plots of the same cell over
images taken at different times, and a manual draw is prone to error.

Regards

Andrew

[Gabriel Landini]

On Thursday 05 March 2009 10:49:16 Andrew Bell wrote:
> Is there a facility within ImageJ to automatically draw the major axis on
> the ellipse that bounds an ROI?

This was discussed very recently here list in relation to Feret diameters.
Check the list archives.

G.

[AJBell]

Thank you - please accept my appologies for the repeat question: it turns
out I asked this question last week. Enough said.

[Wayne Rasband]

> Is there a facility within ImageJ to automatically draw the major axis
> on
> the ellipse that bounds an ROI?
>
> If the image has been thresholded and ROI selected, the "measure" tool
> will calculate the major and minor axis of the bounding ellipse, so it
> must be possible to combine this with the draw function. I am however
> not
> well versed enough to do it myself!
>
> I want to do this to compare line profile plots of the same cell over
> images taken at different times, and a manual draw is prone to error.

The DrawEllipse macro at

     http://rsb.info.nih.gov/ij/macros/DrawEllipse.txt

draws the best fit ellipse as well as the major and minor axis. It
could be easily customized to only draw the major axis.

-wayne