The Probert Encyclopaedia of Science & Technology

IMAGE INTENSIFIER

An image intensifier is a device similar to a television camera which registers faint differences in reflected light from a target area. These differences are then fed through an electronic amplification circuit, giving a gain of 50 times. The resulting image is then referred through the circuit twice more (three times being the limit before distortion sets in) to give an image intensification of some 125,000X. The resulting image is sufficient to identify a man-sized target at 300 meters or a vehicle at 500 meters. The early image intensifiers were developed for military purposes and had two drawbacks. Firstly they were bulky and secondly they emitted a supersonic whistle which while inaudible to humans, disturbed wildlife and thus alerted the targets that they were being observed. During the 1980s a second generation of smaller
image intensifiers were developed using a new type of circuitry which didn't whistle, but at the expense of a little gain.
Image intensifiers are now used by the medical industry and television camera crews (notably during the Iraq-Kuwait War) as well as the military and police.
Research Image Intensifier