image intensifier

Definition: Opto-electronic instrument designed to make something out of nearly nothing i.e. to obtain an image at extremely low light levels of e.g. moonless nights. * The dim image is projected by the light-gathering lens onto a screen that projects a slightly amplified image onto another screen which relays a further amplified image to another screen and so on: each step builds on the previous steps to give very great increases in sensitivity while minimising the effect of noise. * Photo-multiplier tubes used in drum scanners are another type of image intensifier which goes some way to explaining their superiority over CCD-based scanners.

Related Terms: noise

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