import cv2
import numpy as np
import matplotlib.pyplot as plt

img = cv2.imread('IMG_20180522_211242_2.jpg')
pts1 = np.float32([[58,642],[147,627],[83,733],[168,716],[2320,2654],[2291,2566],[2238,2675],[2211,2588]])
pts2 = np.float32([[50,50],[150,50],[50,150],[150,150],[2100-50, 2970-50],[2100-50,2970-150],[2100-150,2970-50],[2100-150,2970-150]])
size = (2100,2970)

M, mask = cv2.findHomography(pts1,pts2)
dst = cv2.warpPerspective(img,M,size)

plt.subplot(121),plt.imshow(img),plt.title('Input')
plt.subplot(122),plt.imshow(dst),plt.title('Output')
plt.show()