Article

Assessing optical radiation exposure to opaque incandescent materials by picture analysis − Part 2: from pixel radiance to eye irradiance

Institut national de recherche et de sécurité (INRS), 1, rue du Morvan, CS 60027, 54519 Vandoeuvre-lès-Nancy Cedex, France

^* Corresponding author: jean-marc.deniel@inrs.fr

Received: 31 October 2023
Accepted: 20 June 2024

Abstract

Incandescent materials emit optical radiation that can cause cataracts, especially in industrial processes. This risk must be assessed to help employers choose an effective means of protecting workers. Where possible, this is done by software simulation. Otherwise, near-infrared irradiance must be measured at the worker’s eye. Since radiometers and spectroradiometers are too expensive for most preventers, a novel and virtually free method has been proposed. Using a photograph, it assesses irradiance by summing the irradiance corresponding to each pixel representing the opaque glowing materials in the image. Pixel irradiance is evaluated 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. The first principle − converting pixel color to radiance − was the subject of a first paper. This paper presents the second principle: calculating irradiance at the eye from pixel radiance. This method is accurate enough to assess cataract risk, thereby helping employers to protect workers. An easy and inexpensive way to calibrate the camera is under investigation in view to making it widespread.