| 摘要 |
<p>An observer in a helicopter 1 track a fugitive 2 and police 4, 5 using a infra-red camera. In order to distinguish the people, each policeman eg 5 eases a infra-red beacon in his helmet which emits a distinctive pulse pattern and which can be seen by the observer via the IR camera. The beacon may use a plurality of IREDs, whose output may be collimated by a lens. Application to other persons, objects or fixed locations is mentioned.</p> |
