Re: mark a zone with 2 vertical lines within a picture, automaticaly

Posted by Justin McGrath on Dec 30, 2007; 5:38pm
URL: http://imagej.273.s1.nabble.com/Plugin-announcement-Orientation-measurements-tp3697674p3697678.html

The Hough transform would be useful here, but I don't know of a plugin
that implements it for ImageJ.  Since your situation is just vertical
lines, you can simplify it.  If you use "Find edges" and add together
all of the pixel values in a column, then the two highest values in
the new array should be the vertical lines in your image.   The lines
are probably not perfectly vertical, so you might want to smooth the
array first.

Justin

On Dec 27, 2007 8:41 AM, Rewald, Boris <[hidden email]> wrote:

> Dear list,
>
> I would like to mark an approx. 7 cm wide (x 20 cm height) zone within a 19
> cm wide (x 20 cm height) jpg picture with vertical lines (in colour?).
>
> I will only include this aperture in the planed analyse but need the
> surrounding to move an overlay in the next time stack (WinRhizo Tron, Regent,
> Canada --> root growth/decay analysis). Because I have > 2000 pictures, it
> would be a pleasure if this marking would be done automatically ... .
>
> I sounds quite easy, but I didn't get the point now ...
>
>
> Thanks a lot for any comments & a happy new year for all of you!!
>
> Boris
>