This document discusses image noise reduction systems. It defines two main types of images - vector images defined by control points and digital images defined as 2D arrays of pixels. It describes different types of digital images like binary, grayscale, and color images. It then discusses image noise sources, types of noise like salt and pepper, Gaussian, speckle and periodic noise. Various noise filtering techniques are presented like minimum, maximum, mean, median and rank order filtering to remove salt and pepper noise.