Pinchuk B. Thermal imaging viewing systems of unmanned aerial and space devices

The dissertation work is devoted to solving the scientific problem of improving the image quality and efficiency of unmanned, aviation and space thermal imaging viewing systems by matching the parameters and characteristics of the system, changing the focal length of the objective and additional rotation angles of sighting. The first section reflects the relevance of this topic based on an overview of the areas of application and purpose of thermal imaging viewing systems (TIVS), that is analysis of the current state and prospects. The conditions in which aircraft TIVS work are considered and the modern requirements necessary to formulate the purpose and tasks of research are defined. The directions of research of ways of improvement of technical characteristics of TIVS which are based on the analysis of dependence of quality of the thermal imaging image on arbitrary angles of sighting and accounted of dynamic of movement are substantiated. In the second section processes are formalized that form the image of the moving TIVS when the deviation of the TIVS at the angles of sighting from the nadir that which will estimate the amount of blur and deformation of the projection points of the focal plane array (FPA). A model for determining the velocity of the observation point is proposed, which allows to calculate the velocity of the image movement in the focal plane, depending on the trajectory of the orbit, coordinates and inclination of the spacecraft. A model for determining the angular velocity of the TIVS additional rotation to solve the problem of effective observation of an object over a long period of time is described. The technique of angular motion is described, which describes the physics of deformation of the projection points of the FPA on the Earth's surface (ES) during the deviation of the TIVS at the angles of sighting. The third section is devoted to the development and improvement of a physical and mathematical model (PMM) for the study of the conversion of infrared radiation from ES to a thermal imager (operator) under different conditions of observation. In this section the basic analytical expressions and dependences are received, techniques are developed and algorithms of calculations which will be used for the analysis of quality and efficiency of TIVS are described. PMM information transformations for TIVS aircraft are developed, which takes into account the characteristics of observation conditions, backgrounds, objects, motion dynamics, optical system and FPA. An algorithm is presented that allows to calculate the spatial resolution and to simulate the deformation of the projection of the FPA’s pixels on the plane taking into account the curvature of the Earth. Possible ways to improve the technical characteristics of the main blocks of the system involved in the formation and transformation of information, and to improve the linear resolution on Earth’s surface (LRES) are identified. The fourth section is devoted to the development of new methods to increase the spatial resolution of the TIVS, the coordination of components and parameters of the TIVS and analysis of their effectiveness. The dependence of the modulation transfer function (MTF) on the presented TIVS constructions is analyzed and shown. The proposed solution is related to the problem of shifting the mercury cadmium telluride matrices with the TDI. The need for additional rotation of the TIVS at the angle of yaw is substantiated. A model is developed for determining the required angular coordinates and angular velocities for additional rotation of the viewing angles at the appropriate time. An approach has been proposed that keeps the spatial resolution almost constant throughout the field of view by changing the focal length of the objective when it deviates from nadir. The formula is obtained for determining the effective path length for sloped routes, which takes into account the rarefaction of the atmosphere and is necessary to calculate the transmittance of the atmosphere. An expression is proposed that reflects the dependence of SNR on the angles of sighting, taking into account the influence of the atmosphere. On the basis of the developed PMM the software which allows to estimate quality of the developed thermal imaging and television systems of supervision and to synthesize new systems is created. The fifth section focuses on the experimental verification and confirmation of the obtained PMM by computer simulation in famous software products and using a digital camera. The effect of a parallel line, which occurs when the deformation of the projection of pixels on the ES due to the deviation of the viewing angles, and the physical principle of forming projections of conditional lines of rows and columns, which explains the manifestation of this effect. Theoretically is obtained results were confirmed by modeling in the programs "Compass 3D" and "Zemax", as well as by the results obtained on a digital camera.