Python - Contornos

import cv2

import numpy as np

import skimage.io as io

import matplotlib.pyplot as plt

img = cv2.imread('circulos.jpg',0)

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

#EROSION

erosion = cv2.erode(img,kernel,iterations = 1)

#DILATACION

dilatacion = cv2.dilate(img,kernel,iterations = 1)

#CONTORNO

contorno = cv2.morphologyEx(img,cv2.MORPH_GRADIENT,kernel)

plt.imshow(contorno, cmap='gray')