ERRORS IN THERMAL IMAGERS TEMPERATURE RESOLUTION DETERMINING

Abstract

Thermal imaging methods of environmental observation are often accompanied by the need to quantify the temperature distribution on the object’s surfaces. In such cases, the accuracy of modeling the information conversion processes that occur in thermal imaging systems is essential. All questions concerning the determination of thermal imagers temperature resolution are important. Experimental methods for determining temperature resolution in this sense are quite unambiguous and well-established in practice. And calculation methods are still being refined and are of interest to the scientific community.
 The article is devoted to the development of practical methods for calculating the thermal imagers temperature resolution. Such methods must be on the hand one accurate enough, and on the other hand - simple enough to be used in design organizations. The definition of the calculations error is also considered. The calculation model is based on the concept of equivalent noise temperature difference NETD as the most general characteristic of energy transformations in thermal imaging observations. The definition of NETD is based on the use of the thermal imager signal transmission function. A simplified version of the calculation method and an example of determining the temperature resolution for a thermal imager with a microbolometric matrix detector are presented. Such thermal imagers currently occupy a significant part of the market and the calculation of the characteristics of the device with a standard specification may be of interest to specialists. The influence of some elements of the mathematical information transformations model on the temperature resolution is shown. For example, as the background temperature increases, the temperature resolution decreases. The analysis of the proposed calculation model allowed us to outline ways to improve (reduce) temperature resolution. A feature of the developed methods is the possibility of their use for different thermal imaging systems, for example, for polarizing thermal imagers.