A flying spot scanner uses a high resolution, high light output, low persistance Cathode Ray Tube CRT to scan an image, usually from motion picture film or a slide. The output of the scanner is usually a television signal. As the electron beam is drawn across the face of the CRT, it creates a scan that has the correct number of lines and aspect ratio for the format of the signal. The image of this scan is focused with a lens onto the film frame. it's light passes through the image being scanned and is converted to a proportional electrical signal by Photomultiplier tube(s), one for each color--Red, Green, Blue--detect the variations in intensity of the beam spot as it scans across the film, and are converted to proportional electrical signals, on for each of the color channels. Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT The cathode ray tube or CRT, invented by Karl Ferdinand Braun, is the display device that was traditionally used in most computer displays, video monitors, televisions and oscilloscopes. ... Photomultipliers, or photomultiplier tubes (PMT) are extremely sensitive detectors of light in the ultraviolet, visible and near infrared. ...

Telecines that use a monochrome CRT as the light source can be referred to as flying spot scanners. Historically, flying spot scanners were also used as primitive live action studio cameras at the dawn of electronic television, in the 1920s.[1] A projector equipped with a spinning perforated disc created the spot that scanned the stage. This required a completely dark stage, and was impractical for production use, but gave early researchers a way to generate live images before practical imaging pickup tubes were perfected. Telecine (pronounced teli-SEEN or teli-SINI) is the process of transferring motion picture film to a video format, such as television, or a machine used to complete this process. ...