How to compute two Dimensional SNR
Basically I am working on the compressed response(poin target) of an image. Here in image i have a point target(white bright dot) and in zoom your can see its RGB cells. I want to compute 2 Dimensional SNR of point target. Point target is the signal and rest of it is noise.
This processed image has an array of (512x1024)rows*coulums= 524288 pixels
My approach is follow the basic formula SNR= 10log(Psignal/Pnoise)
The point target (white bright point) has a main lobe(compressed response) (bump)
The rest are side lobes.
##Power_signal= Main_loob Energy/pixels covered by point target##Power_noise= Rest side lobes/(Total Pixels - pixels of point target)##
I am working on this approach and not completed yet...
I need guidance on 2D SNR:

Is my approach correct
2)Do we consider back ground as noise or not
3)Any other methods that will make the problem easy to solve