Measuring signal intensity from an area enclosed between two ROIs

Posted by Avinash Kali on Oct 29, 2010; 6:06am
URL: http://imagej.273.s1.nabble.com/Measuring-signal-intensity-from-an-area-enclosed-between-two-ROIs-tp3686543.html

I am trying to measure the signal intensity from a ring-like structure in my image.

I drew an ROI enclosing the inner circle of the ring and another ROI enclosing the outer circle of the ring. I have noticed that in ImageJ 1.43 we can select multiple ROIs from ROI manager at the same time. This makes the two ROIs appear at the same time on the image. But how can I measure the signal intensity from the area enclosed between these two ROIs?

I know that by calculating the signal intensities from the two ROIs and using some simple math we can calculate the signal intensity from the area of interest. But this method may not be entirely correct.

Thank You.

Avinash.