Re: error in binary options help?

Posted by Gabriel Landini on Jun 03, 2008; 2:29pm
URL: http://imagej.273.s1.nabble.com/error-in-binary-options-help-tp3696081p3696084.html

On Tuesday 03 June 2008 14:39:14 Michael Schmid wrote:
> you are right that "opening and closing are idempotent procedures".
> Nevertheless, the "iterations" count influences the result a lot!

Oh I see, In this case the opening would be n erosions followed by n
dilations. Yes that is correct.

> A side remark - for large iteration counts, it is faster to
> use Process>Filters>Minimum and Process>Filters>Maximum instead
> of "dilate" and "erode".
> These operations also have the advantage that they have a
> circular, not a square kernel, which is usually desirable.

Yes, that is right, however the results are (obviously) not the same).

> The downside: there is not 1:1 correspondence, it depends on
> the setting of "black background" whether "Dilate" is Maximum" or
> "Minimum".

That is called "polarity". IJ is so flexible that it can sometimes become
confusing! (and I haven't mentioned Inverted LUTs! :-) )

Regards

Gabriel