img1 = imread('lenna512.bmp');
img2 = imread('lenna512_low_dynamic_range.bmp');
[h1 w1] = size(img1); %Get image size of img1
img1 = double(img1);  %Convert the unit8 image to double
img2 = double(img2);
B = 8;                %Encode a pixel using 8-bit binary
MAX = 2^B-1;          %Calculate how many gray levels the image has
MSE = sum(sum((img1 - img2).^2)) / (h1 * w1);   %Calculate the mean square error
PSNR = 20 * log10(MAX / sqrt(MSE));           %Calculate the PSNR in dB