measure distance from pixels to object

[Ofra Golani]

Hi

I have a florescent image with one big object and many small objects.
I want to
- Locate the big object, and all the other objects
- Measure the size (area) of each group
- For every pixel of the small objects I need to measure its shortest distance to the big object.

I can detect the big object and the small objects using Analyze particles with proper size limit.
How do I convert them into masks or groups and then how can I measure the shortest distance between each pixel in one group to the big object ?

Thanks,
Ofra Golani