How to Rotate an Image by an angle in OpenCV Python

You can rotate an image by an angle using OpenCV Python by following the given steps. I highly recommend you get the “Computer Vision: Models, Learning, and Inference Book” to learn Computer Vision.

Step 1

Import the required libraries. If OpenCV is not installed in your system then first install it using This Method.

import cv2
#cv2 is used for OpenCV library
import numpy as np

Step 2

Now Read the Image. The image should be in the current working directory. Otherwise, mention the location of the image.

img =cv2.imread('cat.jpg')

Step 3

First, calculate the center of the image then rotate the image 30 degree anticlockwise from center.

img_center = (np.array(img.shape[1::-1]) / 2)
matrix = cv2.getRotationMatrix2D(img_center, 30 , 1.0)

Step 4

Now apply the above matrix to the image and use the method cv2.warpAffine.

rotated_img = cv2.warpAffine(img, matrix, img.shape[1::-1], flags=cv2.INTER_LINEAR)

Step 5

Now display both images.

cv2.imshow('Cat',img)
cv2.imshow('Rotated Image',rotated_img)
cv2.waitKey(0)
cv2.destroyAllWindows()