I have a gray scale image produced by an optical photon simulation and I am trying to find the DC gain of the image using Matlab. For that, I simulate a slant edge image in the simulation where N number of photons are incident on the optical plate.
I use the edge image to find the line spread function of the edge by taking the first derivative of the edge spread function (
LSF=diff(ESF)). Then I use the Matlab FFT function to find the DC gain at frequency = 0.
I am not sure if this method is correct or not. How do I correctly find the DC gain in my image?.