An image projection apparatus 20 performs spatial light modulation on unpolarized light indicating a projected image, generates projection light set into a polarization state based on a superimposed image, and projects the projection light onto a surface of projection 50. An image processing apparatus 40 calculates each direction of polarization in units of pixels using polarization images in at least three or more directions of polarization acquired by imaging the surface of projection 50 onto which the projection light is projected. Furthermore, the image processing apparatus 40 converts the calculated direction of polarization into a pixel value, and generates a reconstructed image. It is, therefore, possible to generate the projection light indicating the superimposed image invisibly superimposed on the projected image, and to visibly reconstruct the superimposed image from a captured image of the surface of projection onto which the projection light is projected.