Sum of squared differences
m = ssd(i1, i2) is the sum of squared differences between the two equally sized image patches i1 and i2. The result m is a scalar that indicates image similarity, a value of 0 indicates identical pixel patterns and is increasingly positive as image dissimilarity increases.
zsdd, sad, ncc, isimilarity
Machine Vision Toolbox for MATLAB © 1990-2014 Peter Corke.