How to detect rotated object (template matching)?

Question

Python

I am just learning.
This standard code detects the selected template in the picture.
But how to make detection if the picture is rotated and let's say black and white?
Does anyone have examples of implementation? Thank you.

import cv2
import numpy as np
img = cv2.imread("simpsons.jpg")
gray_img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
template = cv2.imread("barts_face.jpg", cv2.IMREAD_GRAYSCALE)
w, h = template.shape[::-1]
result = cv2.matchTemplate(gray_img, template, cv2.TM_CCOEFF_NORMED)
loc = np.where(result >= 0.4)
for pt in zip(*loc[::-1]):
    cv2.rectangle(img, pt, (pt[0] + w, pt[1] + h), (0, 255, 0), 3)
cv2.imshow("img", img)
cv2.waitKey(0)
cv2.destroyAllWindows()

Answer 1

https://medium.com/@deepanshut041/introduction-to-...

Answer 2

Learn to read documentation.
From there it follows that the function works like a fold - which means that you need to expand the template.