Performance of the Eye-Safe LRS and Color CCD Camera Under Aerosol Environments

Abstract

In this paper, we performed an experiment to compare the observation performance of color CCD camera and the distance measurement characteristics of the eye-safe laser range scanner in a non-visible environment, which simulated atmospheric environments in the reactor building when a severe accident occurred at the nuclear power plant. For the comparison experiments, we fabricated a fog room. Fog particles are sprayed into the fog room until they reach a certain concentration at the time of the severe accident. In this paper, different methods are used to evaluate the performance of the camera and the eye-safe laser range scanner. To verify the observation performance of the color CCD camera under the dense aerosol environments, we calculated contrast from the observation image captured by the camera. And to evaluate characteristics of the eye-safe laser range scanner module, we reviewed the range measurement error under the same visibility constraint situations. In comparative tests, the CCD camera used is a general purpose model with a high magnification zoom lens. We evaluated a model with an effective measuring distance of 30 m, referring to the eye-safe laser range scanner module mounted on the Quince robot III. A visibility was introduced as quantitative evaluation parameter for comparing the monitoring performance of the color CCD camera and range measurement error of an eye-safe LRS module under aerosol environments where the fog particles are sprayed in the fog room. The visibility was calculated by attenuation of the He–Ne laser intensity in the fog room where the fog particles are being sprayed.