Modulation transfer function of the thermal imaging monocular

V H Kolobrodov

doi:10.20535/radap.2019.78.74-78

Abstract

The modulation transfer function (MTF) of thermal imaging monocular (TIM) was investigated in this article. TIM consists of a lens, a microbolometric matrix (MBM), an electronic system of video signal amplification and processing, a micro display and an eyepiece. The monocular is considered as a linear invariant incoherent system. It’s MTF is equal to the product of the modulation transfer functions of the components. For the convenience of practical application, it is proposed that all MTFs are considered as a function of the angular spatial frequency in the space of objects. An example of TIM MTF calculation with given characteristics was considered. The study of the MTF showed that the spatial impact of the MBM, which is determined by matrix structure, has the greatest influence on the deterioration of this function.

Highlights

Thermal imaging systems are widely used in various fields of human activity, including security systems, medical thermal diagnostics, aeronautical and space systems, remote sensing of the Earth’s surface, military affairs, etc. [1,2,3,4,5]
There is a lack scientific and technical information about the development of methods for determining the modulation transfer function (MTF) of a thermal imaging monoculars (TIM), which consists of objective lens, microbolometric matrix (MBM), electronic system, display and eyepiece
The electric video signal from the MBM is processed by the electronic system and enters the micro display, which forms the image of the object on the screen

Summary

Introduction

Thermal imaging systems are widely used in various fields of human activity, including security systems, medical thermal diagnostics, aeronautical and space systems, remote sensing of the Earth’s surface, military affairs, etc. [1,2,3,4,5]. The main characteristics of TIM are the spatial and temperature resolution, the maximum detection and recognition distances. They depend on the modulation transfer function (MTF) of the monocular [6,7,8]. Significant amount of scientific papers [9,10,11,12,13,14,15] are devoted to investigation of the thermal imagers MTF, the main components of which are the lens and the radiation detector. There is a lack scientific and technical information about the development of methods for determining the MTF of a TIM, which consists of objective lens, microbolometric matrix (MBM), electronic system, display and eyepiece. Eyepiece that will optimize the characteristics of the monocular to solve a particular observation problem

Physic-mathematical model of thermal imaging monocular

Problem formulation

Modulation transfer function of thermal imaging monocular

Analysis of the TIM MTF

Conclusions