Hi johngan, I am recently trying to do this incidence angle normalization using the equation in the article you recommended. But I am confused. Could you please help me out?
As you said, as the incidence angle gets wider, the brightness of the images gets progressively darker, which means a smaller backscatter (db) for larger incidence angle (for example 40 degree). Since cos(40degree) is smaller than cos(35degree), which means when applying the equation 
, backscatter for a new incidence angle of 35 degree could be even smaller! Is that reasonable? I am expecting it to be bigger.