Image Subtraction using Pillow

Overview:

Subtracting an image from another image results in an image with the differences between the two.
When an Image I₂ is subtracted from another Image I₁ the resultant image I_o will have its pixel values given by

pI_o(x,y) = pI₁(x,y) – pI₂(x,y)

The example Python program works on two digital images taken on a rainy day as an automobile moves by. The images are probably microseconds apart having very few differences among them.When subtracted, the differences are apparent - the lamp post on the left hand side, few splashed water drops and the water drops on the bottom portion of the windshield.
Image subtraction has its applications in variety of fields including Astrophotography and Remote sensing.
Digital Subtraction is a widely used technique in Medical Imaging as in the case of Digital Subtraction Angiography and studies involving disease prognosis.

# Python example program for image subtraction

from PIL import Image

import numpy as np

# Paths of two image frames

image1Path = "./windshield1.jpg";

image2Path = "./windshield2.jpg";

# Open the images

image1 = Image.open(image1Path);

image2 = Image.open(image2Path);

# Get the image buffer as ndarray

buffer1 = np.asarray(image1);

buffer2 = np.asarray(image2);

# Subtract image2 from image1

buffer3 = buffer1 - buffer2;

# Construct a new Image from the resultant buffer

differenceImage = Image.fromarray(buffer3);

# Display all the images including the difference image

image1.show();

image2.show();

differenceImage.show();

Input2 to Image Subtraction using Pillow, the Python image processing library.

Output image of Image subtraction using Pillow - The Python Image Processing Library