Base de radiométrie optique is a technical reference that explores the principles and applications of optical radiometry. The book provides a comprehensive overview of how light is measured, quantified, and interpreted in various scientific contexts, from atmospheric studies to remote sensing. It covers foundational concepts such as spectral radiance, irradiance, and reflectance, and discusses the instrumentation and calibration techniques required for accurate optical measurements. The text is organized into clear sections that guide readers through the theory, practical methodologies, and case studies, making it useful for both students and professionals in physics, engineering, and environmental science. The second edition, published in 2001, incorporates updates to reflect advances in detector technology and data processing, ensuring that the content remains relevant to contemporary research and industry practices.