Same as expansion and corrosion operation , Open operation and close operation are also two basic operations in morphology , These two operations are based on corrosion and expansion .

Open operation : First corrosion operation , Post expansion operation . The function is to separate the connected objects , The connection itself is subtle , At the same time, it can remove some isolated points or burrs .

Closed operation : Expansion operation first , Post corrosion operation . The function is to eliminate some small black holes inside the object .

It's easier to understand by looking at two pictures , The first is open operation :

Operation by open operation , The general shape of the object changes little , Some burrs , Bulge , The pixels at the tiny junctions disappear .

The following is a diagram of the closed operation :

As can be seen from the picture above , The closed operation also keeps the general shape of the object , It's just filling some holes in the interior of the object .

Let's look at the last paragraph opencv Simple code for implementation :
import cv2 import matplotlib.pyplot as plt img = cv2.imread("fig.jpg") kernel =
cv2.getStructuringElement(cv2.MORPH_RECT, (20, 20)) open = cv2.morphologyEx(img
, cv2.MORPH_OPEN, kernel) close = cv2.morphologyEx(img, cv2.MORPH_CLOSE, kernel)
plt.subplot(131); plt.imshow(img); plt.title("original") plt.subplot(132); plt.
imshow(open); plt.title("open") plt.subplot(133); plt.imshow(close); plt.title(
"close") plt.show()
Original image , Open operation , The results of the closed operation are as follows :

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