Re: Analyze particle & Flood fill

Posted by Gabriel Landini on Dec 09, 2005; 11:58pm
URL: http://imagej.273.s1.nabble.com/Analyze-particle-Flood-fill-tp3704248p3704249.html

On Friday 09 December 2005 22:26, Philippe Grosjean wrote:
> Now, the flood fill algorithm introduced recently (version 1.32 or 1.33
> if my memory is correct) fills the *inside* of the blobs before
> analyzing them, but excluding holes. So, once you use the flood fill,
> ImageJ becomes aware of holes inside your blobs.

From the IJ News page:
"v1.34l, 15 April 2005
 The "Flood Fill" particle analyzer option enables measurement of nested
particles and causes interior holes to be ignored."

> I tend to agree with you: the algorithm used is not important here. The
> option should better be spelled '[] Fill holes' and it should use the
> flood fill algorithm if you select that option.

I guess that the above means "ignore the holes area as part of the particle"
rather than filling them (and then count particles within particles). So the
flood fill is to extract the connected thresholded area but not holes. (the
particle is flood filled, not the holes).

But even if this option is "off" (so the holes areas *are* counted as part of
the particle area), the "Limit to threshold" seems to override it when "on"
and counts only the thresholded area (without holes).
Can you see the possibility of confusion? (If I am understanding this wrong, I
would be happy to be corrected).

As I see it, Limit to Threshold is useful for the Measure command, but
confusing for the particle analysis.

On Friday 09 December 2005 23:16, Corentin Cras-Méneur wrote:
> In our case, we hardly ever want to measure the "holes'.

That's great, but the idea is to make it flexible enough so it can be used in
both ways.

Cheers,

Gabriel