Find and draw contours (openCV)

import numpy as np

import cv2



img = cv2.imread('opencv-logo.png')

imgray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

ret, thresh = cv2.threshold(imgray, 127, 255, 0)

contours, hierarchy = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_NONE)

print("Number of contours = "+str(len(contours)))

print(contours[0])





cv2.drawContours(img, contours, 4, (0, 255, 0), 3)

#we can change the parameter -1(draw all contours) to 0to8 because the total contours is 9.



cv2.imshow('Image', img)

cv2.imshow('Image GRAY', imgray)

cv2.waitKey(0)

cv2.destroyAllWindows()