| 摘要 |
PCT No. PCT/JP96/01208 Sec. 371 Date Jan. 8, 1997 Sec. 102(e) Date Jan. 8, 1997 PCT Filed May 7, 1996 PCT Pub. No. WO96/35930 PCT Pub. Date Nov. 14, 1996A disc having a plurality of slits radially each of which have approximately the same width as a diameter of a photoreceptor of the sensor, and a rotary chopper, are arranged to coaxially rotate. When one of the slits faces a sensor, the disc and the chopper are rotated at a rotational speed so that the incident infrared radiation into the sensor is chopped 2-16 times by the chopper. At least two sets of sensors, each set of which comprises a plurality of sensors for sensing infrared radiation of different wavelength bands to one another, the sensors being arranged behind the chopper and the disc along a radial direction centered at the rotational axis of the chopper, are provided. Accordingly, because detection signals by scanning a monitored area in a X-direction and a Y-direction respectively are obtained, it is possible to easily recognize the position where the disastrous fire occurs in the visual field and to detect positions of disastrous fires in distinction from one another even if those occur at a plurality of positions.
|
