Abstract: A method and system of image modulation detection of an aircraft exhaust plume by time sequence differentiation is provided. The method comprises the steps of forming two sequential images of the field of view in which an exhaust plume to be detected is located, and forming a differential image from the sequential images showing components of the aircraft's exhaust plume that are modulating at a rate greater than the frame rate of the detection system. The nonmodulating components such as the sky hills, and even the missile body are eliminated from the differential image. Only the plume remains and only the plume is detected. Therefore there is not false alarm note. Each image is formed by a plurality of pixels, wherein each pixel images a portion of the field of view. A value is assigned to each pixel in each of the sequential images that corresponds to one or more characteristics of the pixel.

Abstract: A method and system of image modulation detection of an aircraft or missile exhaust plume or explosives by time sequence differentiation is provided. The method comprises the steps of forming two sequential images of the field of view in which an exhaust plume to be detected is located, and forming a differential image from the sequential images showing components of the aircraft's exhaust plume that are modulating at a rate greater than the frame rate of the detection system. The detection system permits a selection of frame rates so that unwanted (non-modulating) items in the field of view may be eliminated from detection by the threat warning system. The nonmodulating components such as the sky, hills, and even the missile body are eliminated from the differential image. Only the plume remains and only the plume is detected. Each image is formed by a plurality of pixels, wherein each pixel images a portion of the field of view.