# Towards quantitative small-scale thermal imaging

## TL;DR

This paper evaluates the performance of a 3-5 μm thermal imaging system for reliable, quantitative temperature measurement at sub-millimetre scales, addressing non-uniformity and uncertainty to enable precise applications.

## Contribution

It introduces a method to quantify thermal imager non-uniformity and assesses the system's temperature accuracy and source size effects at small scales.

## Key findings

- Achieved a measurement uncertainty of 640 mK for 10 mm targets.
- Demonstrated the system's potential for reliable sub-millimetre thermal imaging.
- Provided a foundation for further development of quantitative thermal imaging techniques.

## Abstract

Quantitative thermal imaging has the potential of reliable temperature measurement across an entire field-of-view. This non-invasive technique has applications in aerospace, manufacturing and process control. However, robust temperature measurement on the sub-millimetre (30 {\mu}m) length scale has yet to be demonstrated. Here, the temperature performance and size-of-source (source size) effect of a 3 {\mu}m to 5 {\mu}m thermal imaging system have been assessed. In addition a technique of quantifying thermal imager non-uniformity is described. An uncertainty budget is constructed, which describes a measurement uncertainty of 640 mK (k = 2) for a target with a size of 10 mm. The results of this study provide a foundation for developing the capability for confident quantitative sub-millimetre thermal imaging.