Norbert Wiener the amount of noise present in a signal by comparison with an estimate of the desired noiseless signal. Wiener developed the filter at the Radiation Laboratory at MIT to predict the position of German bombers from radar reflections. It is necessary to predict the future, because by the time the shell reaches the vicinity of the target, the target has moved, and maybe has changed direction slightly. They even modeled the muscle response of the pilot, which led eventually to cybernetics. The unmanned V1's were particularly easy to model, and on a good day, American guns fitted with Wiener filters
Paley–Wiener integral Paley–Wiener integral In mathematics, the Paley–Wiener integral is a simple stochastic integral. When applied to classical Wiener space, it is less general than the Itō integral, but the two agree when they are both defined. The integral is named after its discoverers, Raymond Paley and Norbert Wiener. Let "i" : "H" → "E" be an abstract Wiener space with abstract Wiener measure "γ" on "E". Let "j" : "E" → "H" be the adjoint of "i". (We have abused notation slightly: strictly speaking, "j" : "E" → "H", but since "H" is a Hilbert space, it is isometrically isomorphic to