How to simulate pixel simulation in Matlab?

I want to simulate the readout circuit of image sensor. The model I want to make has a input of sample picture(bitmap form),and output which is the image added some noise. I have a trouble with modeling the fixed pattern noise which is caused by the fluctuation of transistor parameter(for example,vth,gm,etc) in source follower circuit(SF). Generally,each pixel has one SF. Is it possible for Matlab/Simulink?Please lend the wisdom.(By the way, I have been using matlab/simulink for only 1 year)