An image processing system includes a mark in which an information display portion presenting predetermined information is included in a region formed by a pair of fiducial lines; a camera that is provided to be relatively movable with respect to the mark; an information acquisition unit that acquires the information presented in the information display portion of the mark, out of the image data; a distance calculation unit that calculates a distance from the camera to the mark in an optical axis direction; and an angle calculation unit that calculates a tilt angle of the camera with respect to the mark.