Background: The part of an imaging scene that is not the target of interest.
Back Surface Mirror: A mirror that has the metallic coating (called ‘silvering’) on the back surface of a piece of glass, to prevent scratching of the metallic surface.
Bandpass: The spectral (wavelength) range over which an imaging system operates, or through which an optical element transmits light.
Blackbody: An object which emits the maximum amount of energy that is theoretically possible at the given temperature.
Black Hot: : Infrared (‘thermal’) images are inherently grayscale images. Objects that give the strongest thermal signature can either be displayed as ‘black-hot’, meaning that the strongest thermal signature is displayed in black (or dark colors), or ‘white-hot’, meaning the strongest thermal signature would be displayed in white (or light colors).
Bolometer (also, Microbolometer): An infrared detector which absorbs incoming IR radiation and warms slightly; the electrical resistance across the bolometer changes as a function of temperature, which can be measured and calibrated.
BST: Acronym for Barium Strontium Titanate, which is a pyroelectric detector material often used in longwave, uncooled detectors
BTU: Acronym for ‘British Thermal Unit. In the English measuring system, the BTU is the unit of heat. One BTU is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
