Installation information acquisition method, correction method, program, and installation information acquisition system

A projection method of a projector that is installed at an installation position in a real space, has a projection direction changeable, and projects a second image including a second object, the second image being formed based on a first image including a first object corresponding to the second object, the method comprising:

• first image generation processing for generating the first image where the first object is located on a second position in a virtual space, the second position being corresponding to a first position in a real space,
• first adjustment image generation processing for generating a first adjustment image including the first object which is located on a first side of the first adjustment image with respect to a center of the first adjustment image,
• first projection processing for projecting by the projector the second object onto the first projection position in the real space based on the first adjustment image,
• second adjustment image generation processing for generating a second adjustment image including the first object which is located on a second side of the second adjustment image with respect to a center of the second adjustment image, the second side being opposite side to the first side,
• second projection processing for projecting by the projector the second object onto the second projection position in the real space based on the second adjustment image, and
• adjustment processing for adjusting size of the second object in the real space so as to reduce a gap between the first projection position and the second projection position.