■サンプルコード
import cv2
import numpy as np
from matplotlib import pyplot as plt
img = cv2.imread('maru.png',0)
edges = cv2.Canny(img,100,200)
plt.subplot(121)
plt.imshow(img,cmap = 'gray')
plt.title('input image')
plt.subplot(122)
plt.imshow(edges,cmap = 'gray')
plt.title('canny image')
plt.show()
■実行結果

