Perspective correction in OpenCV using python

Question

I am trying to do a perspective correction of a tilted rectangle ( a credit card), which is tilted in all the 4 directions. I could find its four corners and the respective

Answer 1

I'm writing the answer provided by @Haris in python.

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

img = cv2.imread('test.jpg')
rows,cols,ch = img.shape

pts1 = np.float32([[360,50],[2122,470],[2264, 1616],[328,1820]])

ratio=1.6
cardH=math.sqrt((pts1[2][0]-pts1[1][0])*(pts1[2][0]-pts1[1][0])+(pts1[2][1]-pts1[1][1])*(pts1[2][1]-pts1[1][1]))
cardW=ratio*cardH;
pts2 = np.float32([[pts1[0][0],pts1[0][1]], [pts1[0][0]+cardW, pts1[0][1]], [pts1[0][0]+cardW, pts1[0][1]+cardH], [pts1[0][0], pts1[0][1]+cardH]])

M = cv2.getPerspectiveTransform(pts1,pts2)

offsetSize=500
transformed = np.zeros((int(cardW+offsetSize), int(cardH+offsetSize)), dtype=np.uint8);
dst = cv2.warpPerspective(img, M, transformed.shape)

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