import cv2 as cv
import numpy as np


img = cv.imread('Photos/cats.jpg')
cv.imshow('Cats',img)

blank = np.zeros(img.shape[:2], dtype='uint8')
cv.imshow('Blank Image', blank)

mask = cv.circle(blank, (img.shape[1]//2+45,img.shape[0]//2),100,255,-1)
cv.imshow('Mask',mask)

masked = cv.bitwise_and(img,img,mask=mask)
cv.imshow('Masked',masked)

cv.waitKey(0)