diff --git a/DRPCA_Net/US_ADM_calc_PSNR.m b/DRPCA_Net/US_ADM_calc_PSNR.m
new file mode 100644
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+++ b/DRPCA_Net/US_ADM_calc_PSNR.m
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+function [Metrics] = US_ADM_calc_PSNR(img1,img2)
+%% US_ADM_calc_PSNR Calculates the Peak Signal-to-Noise Ratio.
+%  PSNR = US_ADM_calc_PSNR(img1,img2)
+%
+%   img1: reference image
+%   img2: output image
+%
+%  ----------------------
+% | Code:  Renaud Morin  |
+% | Email: morin@irit.fr |
+% | Date:  July 2011     |
+%  ----------------------
+
+
+%% Initialization
+if nargin~=2
+    error('MATLAB:paramAmbiguous','There must be exactly 2 arguments.')
+end
+if size(img1)~=size(img2)
+    error('MATLAB:paramAmbiguous','Inputs must be of same size')
+end
+
+
+%% Process 
+d= max(abs([img1(:);img2(:)]));
+MSE=sum( (img1(:)-img2(:)).^2 )/numel(img1);
+MSE1 = MSE;
+PSNR=10*log10(d^2/MSE);
+RMSE = sqrt(MSE);
+MSE = MSE/(sum((img1(:)).^2));
+NRMSE = sqrt(MSE*numel(img1));
+% assignement
+Metrics.MSE=MSE1;
+Metrics.PSNR = PSNR;
+Metrics.RMSE = RMSE;
+Metrics.NRMSE = NRMSE;
+
+
+