Oversight, supervision, surveillance all denote the function or duty of watching or guarding for the sake of proper control or direction.
Oversight applies to the function or duty not only of one who is called an overseer or an inspector but of anyone whose duty it is to watch the progress of a piece of work so that no defects or imperfections may occur or to superintend the labors or efforts of a body of workers.
Supervision carries the strongest implication of authoritative powers, of responsibility, and of superintendence; it usually suggests more rigorous direction or closer management than oversight.
Surveillance implies a close watch on persons suspected of being likely to commit misdeeds or offenses against the law or against morals or suffer untoward accidents.