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 Io will have its pixel values given by
pIo(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.
Example:
|
# 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(); |
Output:
Input Image 1:
Input Image 2:
Image1 - Image2:
