import cv2;
import numpy as np;

img = cv2.imread("dang.png", 1);

subimg = img[100:500, 100:1000];
subimg = subimg[:,:,1];
cv2.imshow('image', subimg);

cv2.waitKey(0);
84da6320fbab80cac6b1851fb374cb32fdc9d06a
<mask token>

<mask token>
cv2.imshow('image', subimg)
cv2.waitKey(0)

<mask token>
img = cv2.imread('dang.png', 1)
subimg = img[100:500, 100:1000]
subimg = subimg[:, :, 1]
cv2.imshow('image', subimg)
cv2.waitKey(0)

import cv2
import numpy as np
img = cv2.imread('dang.png', 1)
subimg = img[100:500, 100:1000]
subimg = subimg[:, :, 1]
cv2.imshow('image', subimg)
cv2.waitKey(0)

import cv2;
import numpy as np;

img = cv2.imread("dang.png", 1);

subimg = img[100:500, 100:1000];
subimg = subimg[:,:,1];
cv2.imshow('image', subimg);

cv2.waitKey(0);