lecture 7

Image Algebra
There are two primary categories of algebraic operations applied to
image:
1. Arithmetic operations.
2. Logic operations.
Addition, subtraction, division and multiplications comprise the
arithmetic operations, while AND, OR and NOT makeup the logic
operations. These operations which require only one image, and are done
on a pixel –by-pixel basis.
Arithmetic operations
To apply the arithmetic operations to two images, we simply operate
on corresponding pixel values. For example to add image I1 and I2 to
create I3:
• Addition is used to combine the information in two images.
Applications include development of image restoration algorithm for
molding additive noise, and special effects, such as image morphing
in motion pictures.
• Subtraction of two images is often used to detect motion consider the
case where nothing has changed in a sense; the image resulting from
subtraction of two sequential image is filled with zero-a black image.
If something has moved in the scene, subtraction produces a nonzero