Region of Interest - magic wand

[kaivan29]

Goal: Create a polygonal region of interest.
Approach: I am using magic wand in Region of Interest setup, where seed point x, y and their offsets, and tolerance are set through parameters obtained from an ini file. When I run the program multiple times the feature under magic wand completely changes from what I had set it to. For example, in the ideal case it would return a polygonal shape that I expected (magic_wand_good.PNG), when I ran it the second time it returned me an 1/6th of a circle (magic_wand_bad.PNG).

What should I do to prevent this random behavior of magic wand? Is there another approach that I can implement to achieve the above goal? Any help would be appreciated.


Thank you,
Kaivan

[Hatef.fouladi]

any time that you click on shape you have to click in same position
if you want use it as code first try to use some binary and basic particle analyse code to find center of mass of particles and any time use it for want algorithm