How can we calculate the elements of the`scattering matrix`

(`Spq`

with`p`

and`q`

being the transmit/receive polarizations), for a`Sentinel-1`

image?

Does the image have to be in a`Single-Look Complex (SLC)`

format (contains complex values), in order to calculate the`scattering matrix`

?

I found the formulas that I was looking for in this article: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=1036007

These formulas obviously depend on the`fresnel reflection coefficients`

which can be found here: https://earth.esa.int/documents/653194/656796/Rough_Surface_Scattering_Models.pdf