Effective Radiation Surface as a Universal Parameter for Monitoring Optical Visibility of Objects in the Infrared Wavelength Range

In this work, we investigated approaches for the visibility monitoring of objects in the infrared (IR) wavelength range. Existing approaches are based on the use of the radiation temperature, energy brightness, and radiation strength of objects and their background as measured parameters. With the diversity and variability of external conditions while observing an object and its background during the day and across seasons, these parameters can vary, resulting in significant errors in visibility monitoring of the objects in the IR wavelength range. The use of an additional characteristic [namely, effective radiation surface (ERS)] and the derived characteristics of objects with and without internal sources of thermal energy can help improve the accuracy of visibility monitoring in the IR wavelength range. The proposed characteristic exhibits a linear relationship with the optical flux incident on the surveillance tool from the object and reflects the relationship of the geometric (the object area in the direction of observation) and energy properties of the object, with the capability to observe objects on various backgrounds. The proposed characteristic retains its significance in a wide range of external conditions. This improves the accuracy of visibility monitoring procedures for objects in the IR wavelength range given the variety and variability of the external conditions under which the object and background are observed during the day and across seasons. ERS can be used to monitor the visibility of objects and is a characteristic of objects.