contours_detection.py

import numpy as np
import cv2
img=cv2.imread("olympic.png")
img_gray=cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
ret,thresh=cv2.threshold(img_gray,127,255,0)
contours,heirarchy=cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_NONE)
print("Number of contours="+str(len(contours)))
print(contours[0])
cv2.drawContours(img,contours,-1,(0,255,0),3)
cv2.imshow('image',img)
cv2.imshow('image_gray',img_gray)
cv2.waitKey(0)
cv2.destroyAllWindows()