CALCULATION OF OBJECTS THERMAL IMAGING PARAMETERS FROM UNMANNED AERIAL VEHICLES

• Main Author: L. V. Katkovsky
• Format: Article
• Language: Russian
• Published: Educational institution «Belarusian State University of Informatics and Radioelectronics» 2020-03-01
• Series: Doklady Belorusskogo gosudarstvennogo universiteta informatiki i radioèlektroniki
• Subjects: thermal imaging; unmanned aerial vehicles; minimum detectable and resolved temperature; modulation transfer function
• Online Access: https://doklady.bsuir.by/jour/article/view/2641

This article is aimed at studying the influence of the entire complex parameters on the characteristics of the obtained thermal images when shooting the Earth’s surface from unmanned aerial vehicles. The values of the minimum detectable and minimum resolvable temperature differences are calculated depending on the parameters of the thermal imager, the survey and the size of the object (spatial frequency) for three serial miniature thermal cameras used in aerial surveys of the Earth's surface from unmanned aerial vehicles. Analytical formulas for estimating the minimum resolvable temperature difference are obtained on the basis of a mathematical model of the thermal imager as a linear system of individual components based on the technique that differs from the generally accepted one. Estimates were made for two cases: observation of a thermal image by an operator on a display screen and for the case when an electronic image is analyzed by a threshold algorithm with no operator engaged. For the first time, the influence of the carrier velocity on the overall modulation transfer function of the system and, accordingly, the temperature and spatial resolution of thermal imagers was taken into account. The main components that must be considered when calculating the full modulation transfer function of the system are: a thermal imager lens, a radiation detector, carrier movement and the observer's visual system. Moreover, the parameters of the detector and the speed of the carrier have the greatest influence on the temperatures resolvable by the system.