Thermal imaging, once limited to the defense sector, is increasingly being adopted in the automotive industry, bringing challenges in scaling production and ensuring accurate performance testing. Critical to this is precise characterization using standardized metrics like Minimum Detectable Temperature Difference (MDTD) and Minimum Resolvable Temperature Difference (MRTD), which are complicated by factors like target emissivity and optical attenuation. Infrared radiometers help relate physical temperature to radiometric output but are complex, especially in the longwave infrared (LWIR) range due to self-emission and calibration sensitivity to ambient conditions. As automotive demand grows, miniaturized and well-calibrated radiometers are essential to ensure test accuracy and production efficiency. This presentation explores the design and calibration of such a radiometer, using the Optikos RAD-900 as a case study, and emphasizes the need for experienced calibration services with robust quality systems to support high-volume manufacturing.