The influence and impact of digital images on modern society, science, technology and art are tremendous. Image processing has become such a critical component in contemporary science and technology that many tasks would not be attempted without it. It is a truly interdisciplinary subject that draws from synergistic developments involving many disciplines and is used in medical imaging, microscopy, astronomy, computer vision, geology and many other fields. With a few exceptions, the topics of optical information processing and digital information processing are usually covered in different books, written by experts in one field or the other. It is rare that the two topics are both covered in the same volume. This book is an exception to this trend, and is notable in several different aspects, but especially in its breadth of coverage of both topics. It seems very appropriate to have both general topics covered in the same book, for optical processing systems (defined broadly) commonly include digital systems to drive the optical system and to post-process the data (example: adaptive-optic systems), while digital processing systems most commonly operate on data that has been gathered by an optical system. As a consequence, sophisticated image-gathering and handling systems today include both types of technology, a merger that grows more complete as time progresses. Indeed, even consumer-oriented devices such as digital cameras are sophisticated systems with optical and digital parts. This is a text for use in a first practical course in image processing and analysis, for final-year undergraduate or first-year graduate students with a background in biomedical engineering, computer science, radiologic sciences or physics. Designed for readers who will become “end users” of digital image processing in the biomedical sciences, it emphasizes the conceptual framework and the effective use of image processing tools and uses mathematics as a tool, minimizing the advanced mathematical development of other textbooks.