| 摘要 |
<p>PURPOSE:To prevent tunnel lighting control, based on the signal from an outdoor luminance meter, from operating in duplication due to tunnel lighting, by outputting the signal where influence of tunnel lighting is removed from outdoor luminance. CONSTITUTION:A hood 1 and an aperture 2 for shielding light from outside of round field of vision of 20 deg., a diffusion board 3 for uniformalizing incident light in terms of plane for solving output nonuniformity problem, a light- detecting part 4 for measuring mean luminance in the angle of field of vision whose center is a tunnel pit mouth before the entrance of the tunnel, and a low frequency filter 5 for removing the output signal, based on beams of above the lighting frequency incident on the light-detecting part 4, from the output signal of the light-detecting part 4, are provided.</p> |
