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CCDs containing rows or grids of capacitors are used in digital cameras, optical scanners and video cameras as light-sensing devices. An image is projected by a lens on the capacitor array, causing each capacitor to accumulate an electric charge proportional to the light intensity at that location. A one-dimensional array, used in line-scan cameras, captures a single slice of the image, while a two-dimensional array, used in video and still cameras, captures the whole image or a rectangular portion of it. Once the array has been exposed to the image, a control circuit causes each capacitor to transfer its contents to its neighbour. The last capacitor in the array dumps its charge into an amplifier that converts the charge into a voltage. By repeating this process, the control circuit converts the entire contents of the array to a varying voltage, which it samples, digitises and stores in memory. Stored images can be transferred to a printer, storage device or video display. CCDs are also widely used as sensors for astronomical telescopes, and night vision devices.
A very interesting astronomical application is to use a CCD in a telescope that is not tracking, i.e. it is not following the motion of the sky, but instead transferring the charges in the CCD and reading them in a direction parallel to the motion of the sky, and at the same velocity. In this way, a region of the sky much larger can be imaged.
CCDs are typically sensitive to infrared light, which allows infrared photography[?], Night-vision devices, 0 lux (or near 0 lux) video-recording/photography.
wikipedia.org dumped 2003-03-17 with terodump