Infrared thermal imaging camera to measure low temperature thermal fields

TL;DR

This paper presents a cooled infrared thermal imaging camera designed for precise low-temperature measurements, utilizing a novel internal calibration method to achieve high accuracy in biological tissue studies.

Contribution

The authors developed a specialized thermal camera with an internal shutter and emissivity reference for accurate low-temperature thermal field measurement.

Findings

Achieved 3% measurement error at -150°C.

Successfully used for in vivo biological tissue freeze-thaw studies.

Enhanced calibration method improves low-temperature thermal imaging accuracy.

Abstract

To measure low-temperature thermal fields, we have developed a single-element cooled thermal imaging camera for a spectral range of 8{\div}14 {\mu}m with an internal shutter for radiometric calibration. To improve the accuracy of measuring the temperature of cold objects, we used a shutter with a combined emissivity as an internal reference source of radiation at the input of the device optical unit. With this aim a small mirror was fixed in the center on its surface covered black, thereby ensuring an efficient reflection of radiation in a wide spectral range of wavelengths. When processing the signal for each pixel of the thermal image, the differential value of the detector response to the shutter blackened and mirror areas was used as a reference. A relative measurement error of 3 percent was obtained for the studied objects with a temperature of -150 {\deg}C. The device was successfully used for remote study of thermal field dynamics during freeze-thawing of biological tissues in vivo.