
Chapter 2
Mathematical Preliminaries
2.1 LINEAR OPERATIONS ON PICTURES
2.1.1 Point Sources and Delta Functions
Let Θ be an operation that takes pictures into pictures; given the input
picture/, the result of applying Θ to/is denoted by We call Θ linear if
for all pictures /, g and all constants a, b.
In the analysis of linear operations on pictures, the concept of a point
source is very convenient. If any arbitrary picture/could be considered to be
a sum of point sources, then a knowledge of the operation's output for a
point source input could be used to determine the output for/. The output of
Θ
for a point source input is called the point ...