Optical Gas Imaging With Uncooled Thermal Imaging Camera-Impact of Warm Filters and Elevated Background Temperature

The goal of the presented article is to investigate the impact of warm filters and elevated background temperature on the operation of an uncooled wideband camera used for optical gas imaging (OGI). The noise equivalent temperature difference (NETD) parameter is measured for a VOx wideband OGI camera built for the purpose of the experiments, with and without an interference filter. The results demonstrate that warm filters have a clear effect on the performance of the OGI camera. Based on the standard NETD measurement procedures, a camera-scene noise equivalent temperature difference (CSNETD) parameter is proposed to quantify both the camera and scene noise. The CSNETD measurements are used to evaluate the impact of elevated background temperature on the performance of the OGI camera. Finally, the camera is used to image methane leaks in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) bands. The results are consistent with the presented NETD/CSNETD measurements and confirm the impact of warm filters and elevated background temperature on the operation of the uncooled thermal imaging camera.