| 摘要 |
A device 10 suitable for use by a sports official comprises an optical instrument 12 for projecting onto the ground 18 at a predetermined distance from the device a visual demarcation of a zone defined by rules of play. The optical instrument 12 can be adapted to project the visual demarcation at a predetermined angle to the horizontal and from a predetermined height; the device preferably includes a support which may be a tripod 14 which can be placed over a ball 16; a carrier for the device 10 may be provided which allows carrying of the device 10 on part of a users body such as the forearm. A handheld controller may provide a remote interface to control the device 10. |
