Aerospace Instrument-Making Annotation << Back ESTIMATION OF RADIATION CONTRAST OF GROUND OBJECTS THERMAL SHADOWS V.A. Ovsyannikov, Ya.V. Ovsyannikov A methodological approach and a corresponding mathematical model are proposed for the operational engineering assessment of the radiation contrast of dynamic and static thermal shadows of ground objects observed by airbased thermal imaging devices (TID) in the daytime in clear weather. It is shown that dynamic thermal shadows are due to different amounts of solar radiation reflected from the shadow and its background, while static ones are due to the thermal inertia of a semibounded background array when it is heated under the influence of solar radiation or cools down after the termination of this influence. The main analytical relationships for performing this assessment are presented, taking into account direct and scattered solar radiation falling on objects and the nearby background – the earth’s surface, as well as the thermophysical and optical characteristics of this background. A comparative analysis of the dynamics of the formation of radiation contrasts of thermal shadows of objects in the wavebands of TID 3-5 and 8-12 μm is performed. A practical example of using the proposed model is given. Keywords: thermal shadow, radiation contrast, thermal imaging device. DOI: 10.25791/aviakosmos.7.2023.1350 Pp. 27-33.