A projection system includes a projection apparatus that projects, onto an object, pattern light indicating pattern images obtained by conversion of projection coordinates defined in a projection coordinate system to codes, an imaging apparatus that captures images created on the object by projecting the pattern light onto the object and that generates first captured images, and an image correction apparatus that generates, based on the first captured images, first coordinate conversion information which associates the projection coordinates with imaging pixel coordinates defined in an imaging coordinate system of the imaging apparatus and that corrects a projection image, which is prepared in advance, by using the first coordinate conversion information.