A projection control unit performs control such that a first pattern image in which first feature points are arranged is caused to be projected on a projection surface, and a second pattern image including second feature points corresponding to the first feature points is caused to be projected on a planar projection surface. An acquisition unit acquires, from a photographing unit, a first photographed image of the projected first pattern image and a second photographed image of the second pattern image. An extraction unit extracts second connected components in which the second feature points are connected in a predetermined direction and first connected components in which the first feature points are connected. A shift amount calculation unit calculates shift amounts of the first connected components with respect to the second connected components. A first calculation unit calculates correction information for correcting a projection target image based on the shift amounts.