How do I display the contours of an image using OpenCV Python?

Question

I followed this tutorial from official documentation. I run their code:

import numpy as np
import cv2

im = cv2.imread(\'test.jpg\')
imgray = cv2.cvtColor(im         


        

Answer 1

You should add cv2.imshow("Title", img) at the end of your code. It should look like this:

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)
contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
cv2.drawContours(im, contours, -1, (0,255,0), 3)
cv2.imshow("title", im)
cv2.waitKey()