I have been studying Covariance matrix in SAR polarimetry and I have done a python program that computes the Covariance matrix. Now when I wanted to check whether my program is correct or not , I went to snap and found that for Covariance there are 3 options. Similarly for Coherent Matrix there are 2 options. Now I am confused which one to select. And in the python program, I am selecting each pixel and extracting pixel information. Then getting Shh,Shv,Svh,Svv, then computing the matrices using formulas. So how to validate the result?