Re: Possible bug with perimeter calculation on composite selections

Posted by Chris Bradhurst on Jan 23, 2009; 2:53pm
URL: http://imagej.273.s1.nabble.com/Possible-bug-with-perimeter-calculation-on-composite-selections-tp3693924p3693930.html

On Fri, 23 Jan 2009 14:18:16 +0000, Gabriel Landini <[hidden email]>
wrote:

>On Friday 23 January 2009 13:51:41 Michael Schmid wrote:
>> Hi Chris,
>>
>> partly this has been discussed a while ago in the mailing list, see
>>    https://list.nih.gov/cgi-bin/wa?A2=ind0803&L=IMAGEJ&P=R2098&I=-3
>
>I think that this is a different issue, not the differences due to perimeter
>encoding, but some other problem. The difference is massive (50%
>underestimation).
>As a workaround one could store the ROIs individually and add their perimeters
>afterwards.
>
>G.
>=========================================================================

Gabriel and Michael,

Thanks for responding.  It does seem to have the hallmarks of a bug.  I
might put on some gloves and overalls and go digging into the internals of
the source code tomorrow, however it appears quite complex at first appearance.

Another alternative workaround I am thinking of is to create a single pixel
width outline of the roi as a binary image and count the number of
foreground pixels.  This is obviously not terribly accurate, but probably
sufficient for my purposes.

-Chris.