Opencv learning Day6

Open operation and closed operation

import cv2
import numpy as np

img = cv2.imread('qing.jpg')
# open ： Corrode first , Re expansion 
kernel = np.ones((5, 5), np.uint8)
opening = cv2.morphologyEx(img,cv2.MORPH_OPEN, kernel)
cv2.imshow('opening', opening)
# close ： Inflate first , Corrode again 
kernel = np.ones((5, 5), np.uint8)
closing = cv2.morphologyEx(img,cv2.MORPH_CLOSE, kernel)
cv2.imshow('closing', closing)
cv2.waitKey(0)
cv2.destroyAllWindows()

Gradient operation

Actually, it is the expansion operation minus the corrosion operation , Can get the boundary

import cv2
import numpy as np
img = cv2.imread('qing.jpg')
kernel = np.ones((9, 9),np.uint8)# Determine the scope of each corrosion 
erosion = cv2.erode(img,kernel,iterations = 1)#iterations For the number of iterations , More iterations , The deeper the corrosion 
dilate = cv2.dilate(erosion,kernel,iterations = 1)#iterations For the number of iterations , More iterations , The deeper the corrosion 

res = np.hstack((dilate,erosion))
cv2.imshow('res', res)

gradient = cv2.morphologyEx(img,cv2.MORPH_GRADIENT, kernel)
cv2.imshow('gradient', gradient)
cv2.waitKey(0)
cv2.destroyAllWindows()

Bowler hat and black box

formal hat ： Raw input - The result of the open operation is
Black box ： Closed operation - Raw input

import cv2
import numpy as np

img = cv2.imread('qing.jpg')
kernel = np.ones((21, 21),np.uint8)# Determine the scope of each corrosion 
tophat = cv2.morphologyEx(img,cv2.MORPH_TOPHAT, kernel)
cv2.imshow('tophat', tophat)

blackhat = cv2.morphologyEx(img, cv2.MORPH_BLACKHAT, kernel)
cv2.imshow('blackhat', blackhat)
cv2.waitKey(0)
cv2.destroyAllWindows()