This document provides information about digital image processing. It defines digital image processing as manipulating digital images through a computer, which is a subfield of signals and systems that focuses on images. The document lists some basic knowledge required for digital image processing, including signals and systems, calculus, probability, and basic programming skills. It also outlines several applications of digital image processing such as medical imaging, remote sensing, and pattern recognition. Finally, it provides some examples of companies that employ digital image processing.