A Concise Introduction to Programming in Python

Project: Image Filters

Many common image manipulations can be described as the application of a

filter. An image filter is a square array of coefficients that describes how old

pixel values will be combined to find a new pixel value. Each entry in the array

is a coefficient to be multiplied by the color in that location. The resulting

RGB values are then added together to pro duce the final result. The center

of the filter corresponds to the position of the pixel whose color is currently

being computed.

For example, this is a 3 × 3 filter that takes 0 times the current color (in the

center) plus 1/8 times each of the colors in the surrounding pixels:

1/8 1/8