python 图片相似度

def pil_image_similarity(filepath1, filepath2):
    from PIL import Image
    from functools import reduce
    import math
    import operator

    image1 = Image.open(filepath1)
    image2 = Image.open(filepath2)

    h1 = image1.histogram()
    h2 = image2.histogram()

    rms = math.sqrt(reduce(operator.add,  list(map(lambda a,b: (a-b)**2, h1, h2)))/len(h1) )
    return rms  #相同时返回结果为0，值越大相似度越低

f1 = "C:\\Users\\Administrator\\Downloads\\imgsearch\\test\\TEST2\\1.JPG"
f2 = "C:\\Users\\Administrator\\Downloads\\imgsearch\\test\\TEST2\\2.JPG"
print (pil_image_similarity(f1,f2))