Method, device, and system for temperature calibration and determination of a temperature in a scene

A thermal camera system for temperature calibration of a thermal camera configured to be arranged at a scene and for determination of a temperature in the scene, wherein the thermal camera system comprises:

• the thermal camera;
• a collecting processor configured to, at each time point out of a plurality of time points in a first period of time, collect an ambient temperature representing a temperature at a first part of the scene to obtain collected ambient temperatures spanning over a range of ambient temperatures;
• wherein the thermal camera is configured to, at each time point out of the plurality of time points in the first period of time, collect one or more thermal image sensor signal values corresponding to the collected ambient temperatures and relating to the first part of the scene so as to generate a plurality of thermal image sensor signal values,
• wherein the first part of the scene comprises one or more background areas for which the one or more thermal sensor signal values are collected;
• a calibration function determination processor configured to determine a calibration function as a function fitting the collected plurality of ambient temperatures and the collected plurality of thermal image sensor signal values, wherein the calibration function gives temperature as a function of thermal image sensor value, and
• wherein thermal camera is configured to, in a second period of time, capture a thermal image of the scene comprising thermal image sensor signal values relating to a second part of the scene;
• and
• a temperature determination processor configured to, in the second period of time, determine a temperature at the second part of the scene based on the calibration function and based on one or more of the thermal image sensor signal values comprised in the captured thermal image of the scene and relating to the second part of the scene.