Python通过OpenCV的findContours获取轮廓并切割实例

import numpy as np
import cv2

im = cv2.imread('test.jpg')
imgray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
ret,thresh = cv2.threshold(imgray,127,255,0)
image, contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)

for i in range(0,len(contours)): 
  x, y, w, h = cv2.boundingRect(contours[i])  
  cv2.rectangle(image, (x,y), (x+w,y+h), (153,153,0), 5) 

  newimage=image[y+2:y+h-2,x+2:x+w-2] # 先用y确定高，再用x确定宽
      nrootdir=("E:/cut_image/")
      if not os.path.isdir(nrootdir):
        os.makedirs(nrootdir)
      cv2.imwrite( nrootdir+str(i)+".jpg",newimage) 
      print (i)