| 摘要 |
A light detection value determines concentration of a target component, without using a laser emitter of high laser intensity or a large light collector. By changing orientation of the laser emitter about a horizontal axis, or height of the laser emitter, a laser irradiation position on a ground or water surface is switched between first and second irradiation positions. A photodetector detects first scattered light scattering from the first laser beam at the first irradiation position, second scattered light scattering from the second laser beam at the first irradiation position, third scattered light scattering from the first laser beam at the second irradiation position, and fourth scattered light scattering from the second laser beam at the second irradiation position. A concentration calculator calculates concentration of a target component between the first and second irradiation positions, based on detection values of the first, second, third, and fourth scattered light. |
