Arithmetic operations using OpenCV | Python

Prerequisite: Arithmetic Operations on Images using OpenCV | Basics

We can perform different Arithmetic operations on images e.g. Addition, Subtraction, etc. This is possible because images are actually stored as arrays (3 Dimensional for RGB images and 1 dimensional for the grayscale images).

Importance of Arithmetic Operations on images:

Code for Image Addition –

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import  cv2
import matplotlib.pyplot as plt % matplotlib inline
# matplotlib can be used to plot the images as subplot
  
first_img = cv2.imread("C://gfg//image_processing//players.jpg")
second_img = cv2.imread("C://gfg//image_processing//tomatoes.jpg")
  
print(first_img.shape)
print(second_img.shape)
  
# we need to resize, as they differ in shape
dim =(544, 363)
resized_second_img = cv2.resize(second_img, dim, interpolation = cv2.INTER_AREA)
print("shape after resizing", resized_second_img.shape)
  
added_img = cv2.add(first_img, resized_second_img)
  
cv2.imshow("first_img", first_img)
cv2.waitKey(0)
cv2.imshow("second_img", resized_second_img)
cv2.waitKey(0)
cv2.imshow("Added image", added_img)
cv2.waitKey(0)
  
cv2.destroyAllWindows()
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Output:
(363, 544, 3)
(500, 753, 3)
shape after resizing (363, 544, 3)

 
Code for image Subtraction –



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import  cv2
import matplotlib.pyplot as plt % matplotlib inline
  
  
first_img = cv2.imread("C://gfg//image_processing//players.jpg")
second_img = cv2.imread("C://gfg//image_processing//tomatoes.jpg")
  
print(first_img.shape)
print(second_img.shape)
  
# we need to resize, as they differ in shape
dim =(544, 363)
resized_second_img = cv2.resize(second_img, dim, interpolation = cv2.INTER_AREA)
print("shape after resizing", resized_second_img.shape)
  
subtracted = cv2.subtract(first_img, resized_second_img)
cv2.imshow("first_img", first_img)
cv2.waitKey(0)
cv2.imshow("second_img", resized_second_img)
cv2.waitKey(0)
cv2.imshow("subtracted image", subtracted)
cv2.waitKey(0)
  
cv2.destroyAllWindows()
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Output:
(363, 544, 3)
(500, 753, 3)
shape after resizing (363, 544, 3)

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