% function that scales 2D image functions fin and hin 
% so that they have equal rms

function [f, h] = scale_rms (fin, hin);

 rms_f = sqrt (mean(mean(fin.*fin)));
 
 rms_h = sqrt (mean(mean(hin.*hin)));
 
 beta = sqrt (rms_h / rms_f); % the scale parameter
 
 f = beta .* fin;
 h = hin ./ beta;