1. A remote instruction system comprising: an imaging unit that captures an image of a plurality of objects; a projecting unit that projects an annotation image in an imaging area of the imaging unit, the annotation image being formed in accordance with an instruction issued based on the captured image; and an annotation adjusting unit that adjusts conditions for projecting the annotation image, in accordance with a situation in the imaging area of the imaging unit, wherein the annotation adjusting unit adjusts the projection conditions of the annotation image in accordance with a relationship between the annotation image and at least one of the objects, and the at least one of the objects is positioned in front of a display screen positioned within the imaging area.