>Watershed . The thin skeleton lines (8-conn) of the background are
. Gabriel, the 20th under 4-conn. is a one pixel object at the right
> Gabriel, thank you for the hint. Very helpful! I will see to prepare
> a macro Wand 2 to test the BinaryReconstruction4/8.
>
> Michael, In fact I did not threshold the image! It is a result of
> the Delaunay/Voronoi plugin from Johannes (Dscho?) after some
> broohaha with foreground and background color switches!. However,
> ImageJ1.42c (daily build) selects particels in the described way! I
> think I should preserve that example for tests!
>
> Meanwhile I see and remind me to earlier findings that wand selects
> the next object to the right even if the selection point is not
> inside the object. This is perhaps an explaination for the queer
> selection on the right side!
>
> Thanks again for the quick answers
>
> Karsten
>
> Am 27.11.2008 um 18:11 schrieb Gabriel Landini:
>
>> On Thursday 27 November 2008 16:57:39 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.
>>
>> I think that your image has 4-conn particles. If you run Particles4
>> plugin with the label option you will get 20 particles.
>> If you created this with a watershed/skeletonisation, then to make
>> it easier, you could use a 4-conneected watershed (which should
>> give 8-connected particles).
>>
>> If you analyse the image with the Particles8 plugin you get only 3
>> 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?
>>
>> That is a job for the BinaryReconstruct4 plugin in the Morphology
>> collection. Now this is not compiled into a class, because I have
>> not had time to test it thoroughly. If you test it, please send me
>> some feedback.
>>
>> You could get the XStart YStart points with Particles4, then create
>> a new image with those pixels set for the particles you want to
>> select and BinaryReconstruct4 with the original as mask and the new
>> image as seed.
>>
>> I hope it helps.
>>
>> Gabriel
>