The research of dual-path optical visibility measurement technology

This paper introduced a visibility detecting system of double light path based on the theory of infrared foreword scattering, which has two transmitters and two receivers. The system includes three parts: emitters, detectors and signal processor. This article describes its theory, principal components meanwhile discusses, it solves the technical difficulties in designing circuitry for detection and amplification of the weak signal. It is explained that the precision and stabilization of the visibility meter were improved by pairs of optical path and lock-in amplifier in receiving side. And such improvements have been certified by experiments.