Image scanner incorporating manually operable magnification and brightness control

摘要

A scanner useful as an input device to a television or like display is operable while manually zooming and cropping the image projected onto an image sensor. A fixed image is supported on a movable, hand-manipulated stage that interactively controls the conjugate distances of the optical system so that zooming and cropping is obtained without losing focus. Since zooming the image affects the level of illumination impinging upon the sensor, an automatic brightness circuit varies the illumination according to the signal level. A manually operated altering circuit allows additional user-selected variation of the illumination level. By situating manually operated altering switches on the movable stage, a single hand can control zooming, cropping and brightness without having to interact with a keyboard or like input controls on the display.