如何使用python来判断图片相似度

from PIL import Image
import os
#import hashlib 
 
def getGray(image_file):
   tmpls=[]
   for h in range(0,  image_file.size[1]):#h
      for w in range(0, image_file.size[0]):#w
         tmpls.append( image_file.getpixel((w,h))  )
          
   return tmpls
 
def getAvg(ls):#获取平均灰度值
   return sum(ls)/len(ls)
 
def getMH(a,b):#比较100个字符有几个字符相同
   dist = 0;
   for i in range(0,len(a)):
      if a[i]==b[i]:
         dist=dist+1
   return dist
 
def getImgHash(fne):
   image_file = Image.open(fne) # 打开
   image_file=image_file.resize((12, 12))#重置图片大小我12px X 12px
   image_file=image_file.convert("L")#转256灰度图
   Grayls=getGray(image_file)#灰度集合
   avg=getAvg(Grayls)#灰度平均值
   bitls=''#接收获取0或1
   #除去变宽1px遍历像素
   for h in range(1,  image_file.size[1]-1):#h
      for w in range(1, image_file.size[0]-1):#w
         if image_file.getpixel((w,h))>=avg:#像素的值比较平均值 大于记为1 小于记为0
            bitls=bitls+'1'
         else:
            bitls=bitls+'0'
   return bitls
'''        
   m2 = hashlib.md5()  
   m2.update(bitls)
   print m2.hexdigest(),bitls
   return m2.hexdigest()
'''
 
 
a=getImgHash("./Test/测试图片.jpg")#图片地址自行替换
files = os.listdir("./Test")#图片文件夹地址自行替换
for file in files:
   b=getImgHash("./Test/"+str(file))
   compare=getMH(a,b)
   print file,u'相似度',str(compare)+'%'