Particle Analysis

Posted by Florian Sedlmeir on
URL: http://imagej.273.s1.nabble.com/Particle-Analysis-tp3690320.html

Hi,

I want to analyse particle-like structures with ImageJ. The problem is,  
that these particles usually have a good contrast against their local  
environment, but globally there are too many areas with similar or same  
grey values to threshold the image. So i have a few questions concerning  
this:

- Is there an easy way to threshold only selected areas in a picture (to  
threshold the whole picture step by step)?

- My particles are easily distinguishable with the eye because they are  
not as rough as their environment (+usually  there is a local difference  
in contrast). ImageJ is able to find the edges with the "find edges" tool,  
but unfortunatly it doesn´t create closed areas (my plan was to find  
edges, threshold the resulting picture and analyse the resulting particles  
then) Is there a solution for this a problem?

- One of my friends showed me the "magic wand" tool in Photoshop, which is  
able to determine my particles properly. Unfortunatly the same tool in  
ImageJ is not able to do this, it seems to be too sensitive. (Are there  
parameters which can be adjustet?)
So my question is: Does a plugin exist, which is able to do the same task  
as Photoshop´s magic wand?


Thank you and best regards.
Florian