- noun a photoelectric device which produces a signal related to the amount of light falling on it
- A sensor composed of light-sensitive cells whose output is a numeric representation of intensity and color. Applications include its use in digital cameras, robotics, and in satellite imaging. image tube An electron tube which converts an image from one part of the electromagnetic spectrum into another. For example, a tube whose photosensitive surface converts an infrared image into a visible image which is projected onto a fluorescent screen. Also called image converter (2), or image converter tube.