Hello , Im having one matrix which is product of two FFT transforms of one fits image ( astronomical image ). In that matrix you could find 3 peaks. One largest in center, and two around central peak. Main problem is determining those peaks. I could find central ( largest ) peak by searching for max value in matrix. But, when i want to find out size of central peak i`m having problem due to noise. Im not sure where noise begin and where peak end. So, my question is how to find noise value? And when i find it, peaks will be above that value.