US Patent 7475995 Projector trapezoidal correction

A projector includes an image projecting section that is structured to project an image according to an input image, to a virtual projection plane arranged in a predetermined positional relationship therewith, an imaged-information generating section that has an output-image taking section to take an output image projected to a real projection plane and outputs imaged information containing lightness information having a correlation to a lightness in accordance with an image taken, and a distortion correcting section that corrects a distortion, in an output image for the input images, caused by an inclination of between the virtual and real projection planes, according to the imaged information.