| 摘要 |
The aim is to prevent either too much or too little light from being switched on in the critical entrance and transition zone (E') of a tunnel. To this end, the brightness is measured several times at time intervals within a field of view of 20 DEG directed towards the tunnel entrance portal (P), the individual measurement results are used to calculate a mean value of the external brightness and a desired mean value of the brightness is calculated from the latter for the tunnel entry zone (E'). The brightness (LE) in this zone (E') is determined there several times at time intervals, and these individual measurement results are used to calculate an actual mean value of the entrance zone brightness for the tunnel entry zone (E'). In the event of any overshooting of a predetermined difference between the desired and actual mean values of brightness for the tunnel entry zone (E'), the tunnel lighting in said zone is controlled for the purpose of correction. <IMAGE> |
