Hi could you help me in find goot openCV function to get distance between two images. I need to compare two photo and give verdict if the pair of photos are similar. For example this two are similar http://bluebuddies.com/smurf_fun/smurf_spot_the_difference/jpg/Smurf_Spot_the_Difference.jpg . Two photo of same static object taken one after secound should be similar and give small value of "distance.