Patent ID: 7542074

Claim:
A photographed image projection device comprising: a camera which photographs an object and outputs image data; an image processing unit which carries out image processing on the image data output by the camera; a projection unit which projects an image based on the image data processed by the image processing unit; and a control unit which controls the camera, the image processing unit and the projection unit, so that a frame frequency of the image data output by the camera is switchable to at least two frequencies, wherein the control unit comprises a movement determining section which determines whether an image of the image data output by the camera has movement; wherein the control unit sets in advance, a high/low frame frequency of the image data output by the camera such that: (i) when the movement determining section determines that the image of the image data output by the camera has movement, the control unit controls the camera, the image processing unit, and the projection unit so that the image data is output by the camera with a high frame frequency, and (ii) when the movement determining section determines that the image of the image data output by the camera does not have movement, the control unit controls the camera, the image processing unit, and the projection unit so that the image data is output by the camera with a low frame frequency and so that an amount of data corresponding to a given image increases to thereby achieve a higher image resolution; wherein the movement determining section obtains an image change amount of the image of the image data output by the camera; and wherein the movement determining section determines that the image of the image data output by the camera: (i) has movement, if the image change amount is at least equal to a first predetermined threshold amount; (ii) has a slight movement, if the image change amount is lower than the first predetermined threshold amount and at least equal to a second predetermined threshold amount; and (iii) does not have movement, if the image change amount is lower than the second predetermined threshold amount.