In its first update in 10 years, this text describes the characterization of all modern infrared imaging systems. In this new edition: the concept of target/background [DELTA]T (delta-T) with its dependence on background temperature is clarified; description of the three-dimensional noise model has been expanded with test methods plainly addressed; and, major updates were made to delineate Scanning and staring array methodologies in MTF measurement, and advantages and disadvantages of each are discussed.Although MRT test procedures have not changed very much over the years, observer variability is now well-documented in this title. All figures and graphs have been redrawn in this title. It is copublished with JCD Publishing.