Small-sized thermal imaging camera based on micro-scanning

Abstract

Subject of study. The subject is a thermal imaging camera implementing micro-scanning based on a small-format matrix of 320×256 photodiodes made of cadmium-mercury telluride featuring a spectral range of 8–10 µm.Aim of study. The aim is the creation of a compact thermal imaging camera with a spectral range of 8–10 µm based on a small-format cadmium-mercury-telluride matrix photodetector using gearless electro-mechanical drives for changing fields of view, sub-focusing, calibration, and micro-scanning of the scene to improve spatial resolution parameters and threshold sensitivity. Method. The method involves combined use of technical solutions for the mechanical movement of optical components and correction of residual inhomogeneity of the sensitivity of the photodetector based on micro-scanning of the observation scene. Main results. A thermal imaging camera with micro-scanning based on a small-format matrix photodetector (320×256 pixels of cadmium mercury telluride) with a spectral range of 8–10 µm is developed. The camera uses gearless electromechanical drives allowing micro-scanning of the observed scene, changing fields of view, focusing, and channel calibration. The camera is equipped with a 4× zoom range lens with a maximum field of view of 21.7∘×17.5∘ and a spatial resolution of 2.27mrad−1 in micro-scan mode. The combination of the proposed solutions made it possible to obtain a high-quality thermal imaging device with a temperature difference equivalent to noise equal to 23 mK. Practical significance. The proposed thermal imaging camera can be employed in the fields of non-destructive testing, surveillance, and environmental monitoring. The proposed technical solutions will be useful for evaluating high-resolution parameters and threshold sensitivity of thermal imaging mechanisms using photodetectors in a small-format matrix.