Re: Connectivity used in "Analyze Particle ..." and "Wand (tracing) Tool"

Posted by Michael Schmid on
URL: http://imagej.273.s1.nabble.com/Delaunay-update-tp3694375p3694381.html

Hi Karsten,

funny enough, the wand behaves like "analyze particles" (8-connected)  
if I threshold the image.
Without thresholding, I can reproduce your observations concerning 4-
connected wand selection.

I could not reproduce selecting the background when clicking one of  
the particle at the right side, neither with nor without threshold.

Michael
________________________________________________________________

On 27 Nov 2008, at 17:57, Karsten Rodenacker wrote:

> Hi, Image analysis and -J experts,
>
> I have an example were I don't fully understand the routines  
> "Analyze Particle ..." and "Wand (tracing) Tool"!
>
> The image http://picasaweb.google.com/lh/photo/ 
> 8Yo_5vJ1zLKZGwP22oDgsw delivers under "Analyze Particle ..." three  
> particles (white is foreground). That is understandable, seemingly  
> eight-connected neighborhood (of foreground) is assumed. Possibly  
> four-connectedness could be helpful in such cases with thin lines  
> dividing the particles.
>
> But now, trying to overcome this problem by selecting the particles  
> with "Wand (tracing) Tool", possibly in a macro, I run into  
> difficulties. Clicking into particles on the left side of the image  
> selection is okay, Wand is using 4-connectedness! Clicking into one  
> of the two right-most particles seemingly wand is selecting  
> background!
>
> Is there any way to select one of these two right-most particles?
>
> Help is appreciated
> Regards
> Karsten