1. An image projection device comprising: a drive controller that causes generation of light of a specified color tone by a combination of light to be transmitted by a liquid crystal panel to project image data onto a projection plane; an image capturing controller that receives a synchronization signal that specifies a period in which the liquid crystal panel does not transmit light from the drive controller and causes capturing of an image of the projection plane according to the period that is specified by the synchronization signal; an illuminated image detector that detects, from the captured image of the image data, an illuminated image that is illuminated by an illuminating device on the projection plane; and an illuminated image generator that generates projection image data obtained by combining given image data in a position in which the illuminated image is detected.