The document outlines image arithmetic in digital image processing, detailing operations such as addition, subtraction, multiplication, and division. It highlights various applications of image arithmetic, such as detecting differences between images and superimposing them using MATLAB functions. Additionally, it provides example code for image addition and multiplication functions, emphasizing their usage in scaling and enhancing image properties.

1. Digital Image Processing
Asad Ali. From BCS 6th
3395

2. What is Image Arithmetic?
Image arithmetic is the implementation of standard
arithmetic operations

3. What is Image Arithmetic?
Image arithmetic is the implementation of standard
arithmetic operations, such as
• Addition

4. What is Image Arithmetic?
Image arithmetic is the implementation of standard
arithmetic operations, such as
• Addition
• Subtraction

5. What is Image Arithmetic?
Image arithmetic is the implementation of standard
arithmetic operations, such as
• Addition
• Subtraction
• Multiplication

6. What is Image Arithmetic?
Image arithmetic is the implementation of standard
arithmetic operations, such as
• Addition
• Subtraction
• Multiplication
• Division

7. IA JUICED UP!!

8. Usage of Image Arithmetic
Image arithmetic has many uses in image processing both as a
preliminary step in more complex operations and by itself.
For example:
Image subtraction can be used to detect differences
between two or more images of the same scene or
object.

9. HOW/WHERE you can use
Image Arithmetic?
You can do image arithmetic using the MATLAB arithmetic
operators.

10. HOW/WHERE you can use
Image Arithmetic?
You can do image arithmetic using the MATLAB arithmetic
operators.
But:-
Wait Wait Wait..!!!!!

11. HOW/WHERE you can use
Image Arithmetic?
You can do image arithmetic using the MATLAB arithmetic
operators.
But remember to:
• Convert the images to class.
AND
• Double to use these operators.

12. Adding Images
To add two images or add a constant value to an image.

13. Adding Images
To add two images or add a constant value to an image.
• [imadd] function
adds the value of each pixel in one of the input images with the
corresponding pixel in the other input image and returns the
sum in the corresponding pixel of the output image.

14. USAGE of Adding Images
Image addition has many uses in image processing.
For example:
The following code fragment uses addition to superimpose one
image on top of another. The images must be the same size and
class. You can brighten your image too.

15. USAGE of Adding Images
Image addition has many uses in image processing.
For example:
The following code fragment uses addition to superimpose one
image on top of another. The images must be the same size and
class. You can brighten your image too.
I = imread(‘pic1.tif');
J = imread(‘pic2.tif');
K = imadd(I,J);
imshow(K)

16. USAGE of Adding Images
Image addition has many uses in image processing.
For example:
The following code fragment uses addition to superimpose one
image on top of another. The images must be the same size and
class. You can brighten your image too.
I = imread(‘pic1.tif');
J = imread(‘pic2.tif');
K = imadd(I,J);
imshow(K)

17. Multiplying Images
[immultiply] function.This does an element-by-element
multiplication (.*) of each corresponding pixel in a pair
of input images and returns the product of these multiplications
in the corresponding pixel in an output image.

18. Multiplying Images
[immultiply] function.This does an element-by-element
multiplication (.*) of each corresponding pixel in a pair
of input images and returns the product of these multiplications
in the corresponding pixel in an output image.
Scaling image processing operations.
Scaling brightens an image; a factor less than one darkens an image.
Scaling generally produces a much more natural
brightening/darkening effect than simply adding an offset to the
pixels, since it preserves the relative contrast of the image better.
For example, this code scales an image by a constant factor.

19. Multiplying Images
Example Code
I = imread(‘pic.tif');
J = immultiply(I,1.2);
imshow(I);
figure, imshow(J);

20. Summary of Image
Arithmetic Functions
Function Description
imabsdiff Absolute difference of two images
Imadd Add two images
imcomplement Complement an image
imdivide Divide two images
imlincomb Compute linear combination of two images
immultiply Multiply two images
imsubtract Subtract two images