How to determine the response function of an imaging system?
I'm trying to solve the following problem:
If I had an imaging system in a black box, how could I derive its response function?
My first idea was to use a plane wave, and measure the output. I know that the convolution of the input wave with the response function gives us the output. As we know the input, could we just measure the output to derive the response function?
It seems to easy to me but I'm not sure what else I could do. I could measure the intensity of the outgoing wave, but does that necessarily let me derive what the original wave looked like?
All my textbooks work the other way, they begin knowing the response function to derive a function for the output.
