Create rectangle with known size

Posted by rettl on Jul 06, 2015; 12:48pm
URL: http://imagej.273.s1.nabble.com/Create-rectangle-with-known-size-tp5013429.html

Hi!

Probably an old topic, but I can't find it...

I have different images (all with scale bar on) and I want to create a rectangle on all of them which has the same size in mm (and then crop this region). Although the magnification is not always 100% the same, I want the macro to create a rectangle with the size of 20x30mm. I know how to set scale, but I can't find a solution for "creating a rectangle in a known size".

I am sure this is very easy. Thanks for your ideas!

CL