Posted by
Kenneth Sloan-2 on
Jan 26, 2009; 6:31pm
URL: http://imagej.273.s1.nabble.com/Possible-bug-with-perimeter-calculation-on-composite-selections-tp3693924p3693929.html
It's worth noting that "perimeter" is a notoriously difficult concept
to nail down.
The answer depends on scale, and on what you think a "pixel" is, and
on precisely
where you think the boundary is.
In my opinion, "perimeter" is nearly useless when used across
different studies
done by different observers.
see "How long is the coast of England".
On Jan 26, 2009, at 9:52 AM, Chris Bradhurst wrote:
> On Sat, 24 Jan 2009 09:26:37 +0000, Gabriel Landini
> <
[hidden email]>
> wrote:
>
>> On Friday 23 January 2009, Chris Bradhurst wrote:
>>> 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.
>>
>> Better than pixel counting as estimates of perimeters, you could
>> use the
>> Particles8 plugin which uses Freeman's algorithm to estimate the
>> length of the
>> perimeter (distance 1 for side-connected and sqrt(2) for corner-
>> connected
>> pixel boundaries).
>
> The particles8 plugin works very nicely for extracting perimeters.
> Thanks
> for the tip Gabriel.
--
Kenneth Sloan
[hidden email]