This was used in Vietnam. My neighbor growing up had this condition and was a spotter in Vietnam. He'd be flown over areas of jungle in a helicopter and he woul

This was used in Vietnam. My neighbor growing up had this condition and was a spotter in Vietnam. He'd be flown over areas of jungle in a helicopter and he would be able to easily spot camouflaged structures. He would then photograph them and mark up what he saw. He parlayed this experience into a successful career in photojournalism after he got out of the military.