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def npcr(im1, im2):
    im1 = np.asarray(im1)
    im2 = np.asarray(im2)
    values = [0,0,0]
    for i in range(len(im1)):
        for j in range(len(im1[i])):
            for k in range(len(im1[i][j])):
                if im1[i][j][k] != im2[i][j][k]:
                    values[k]+=1
    length = im1.size/3
    values = [(x/length) * 100 for x in values]
    return values