Apparatus and method for detecting smoke using multi-angle light scattering
An apparatus and method for detecting smoke using multi-angle light scattering. The apparatus includes a light source array in which a plurality of light sources outputting optical signals of a same wavelength are arranged at a regular interval and configured to output the optical signals at different irradiation angles to smoke particles, a lens configured to divert optical paths of the optical signals output from each of the plurality of light sources included in the light source array, an optical detector configured to measure the optical signals that pass through the lens and are scattered and absorbed by the smoke particles, and a computing device configured to classify types of the smoke particles using a scattering coefficient and an absorption coefficient of the smoke particles determined through the measured optical signals.
1 . An apparatus for detecting smoke, the apparatus comprising:
a light source array in which a plurality of light sources outputting optical signals of a same wavelength are arranged at a regular interval and configured to output the optical signals at different irradiation angles to smoke particles;
a lens configured to divert optical paths of the optical signals output from each of the plurality of light sources included in the light source array;
an optical detector configured to measure the optical signals that pass through the lens and are scattered and absorbed by the smoke particles; and
a computing device configured to classify types of the smoke particles using a scattering coefficient and an absorption coefficient of the smoke particles determined through the measured optical signals,
wherein the computing device is further configured to:
identify optical intensity of the optical signals measured by the optical detector;
normalize the identified optical intensity of the optical signals;
using the normalized optical intensity of the optical signals, derive a full width at half maximum (FWHM) of an optical irradiation angle; and
using the derived FWHM, determine the scattering coefficient of the smoke particles.
2 . The apparatus of claim 1 , wherein
the computing device is further configured to normalize the identified optical intensity of the optical signals by subtracting the identified optical intensity of the optical signals by optical intensity of an optical signal corresponding to a minimum value among the identified optical intensity of the optical signals, and then dividing optical intensity of the optical signals remaining after the subtraction by optical intensity of an optical signal corresponding to a maximum value among the optical intensity of the optical signals remaining after the subtraction.
3 . The apparatus of claim 1 , wherein
the computing device is further configured to determine the scattering coefficient of the smoke particles using a calibration curve representing an FWHM of an optical irradiation angle derived according to different scattering coefficients stored in advance by being measured through an experiment or calculated through a simulation.
4 . The apparatus of claim 1 , wherein
the computing device is further configured to determine the absorption coefficient of the smoke particles using intensity of an optical signal output from a light source at an irradiation angle of 0 degrees among the plurality of light sources, intensity of an optical signal when the optical signal output from the light source at the irradiation angle of 0 degrees penetrates through the smoke particles and is measured by the optical detector, and a penetration distance.