from PIL import Image
import itertools
img = Image.open('C:/img.jpg').convert('L') #打开图片,convert图像类型有L,RGBA

# 转化为黑白图
def blackWrite(img):
 blackXY = []

 # 遍历像素点
 for x in range(img.size[0]):
  for y in range(img.size[1]):
   print img.getpixel((x,y))
   if img.getpixel((x,y))<128:
    img.putpixel((x,y),0) # 置为黑点
    blackXY.append((x,y))
   else:
    img.putpixel((x,y),255) # 置为白点
 return blackXY


# 去除干扰点
def clrImg(img,pointArr):
 # 获取周围黑点的个数
 def getN(p):
  count = 0
  x = [p[0]-1,p[0],p[0]+1]
  y = [p[1]-1,p[1],p[1]+1]
  for i in itertools.product(x,y): # 笛卡尔积
   try:
    if img.getpixel(i) == 0:
     count +=1
   except:
    print 'out of'
    continue
  print count
  return count

 for p in pointArr:
  if getN(p)<5: # 周围黑点个数 <5 的黑点认为是干扰点,置为白点
   img.putpixel(p,255)
   
pointArr = blackWrite(img)
clrImg(img,pointArr)
img.save("C:/img_1.jpg")