Assessing optical radiation exposure to opaque incandescent materials by picture analysis – Part 1: from pixel color to radiance

\nIn industrial processes, working on incandescent materials exposes workers to optical radiations that can lead to cataract. In the case where risk cannot be appraised using software simulation, it is necessary to measure visible and near infrared irradiance at the eye of the worker. Since radiometers and spectroradiometers are too expensive for most people in charge of safety at work, a novel method is proposed that assesses irradiance using a photograph taken by smartphone, for example. It consists in summing the irradiance corresponding to each pixel representing the opaque incandescent materials in the picture. Pixel irradiance is assessed from the radiance of the colored body whose temperature and emissivity correspond to the pixel color, weighted by the geometric configuration associated with the pixel in the camera perspective. This virtually free method is accurate enough to assess cataract risk, thereby helping employers to choose an efficient means of protecting workers. In this paper, we present the first principle of the method proposed: temperature and emissivity estimation of incandescent materials. \n