python-图像目标监测（1）识别答题卡

# -*- coding: utf-8 -*-
"""
Created on Thu Dec 20 16:05:10 2018

@author: leizhen.liu
"""

import cv2.cv2 as cv2
import numpy as np

data = cv2.imread('anwser.jpg')
cv2.imshow('anwser',data)


#灰度處理
gray = cv2.cvtColor(data,cv2.COLOR_BGR2GRAY)
cv2.imshow('gray',gray)


kernel = np.ones((5,5),np.uint8) 

#膨脹操作
pengzhang = cv2.dilate(gray,kernel,iterations =1)
cv2.imshow('pengzhang',pengzhang)

#腐蝕
fushi = cv2.erode(pengzhang,kernel,iterations =1)
cv2.imshow('fushi',fushi)


#二值化
ret ,color2 = cv2.threshold(fushi,127,255,cv2.THRESH_BINARY_INV)
cv2.imshow('binary',color2)

#轮廓
_,contours,hierarchy=cv2.findContours(color2,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)  
#newimg=np.zeros_like(color2)   
cv2.drawContours(data, contours, -1, (0,0,255),1)
cv2.imshow('lunkuo',data)

cv2.waitKey(0)

注意点：1、cv2.waitKey() 要写否则图片不能显示。