The contactless detection of vital parameters in humans and animals is crucial for ensuring health. While sensors that touch the body or are invasive can already accurately capture parameters such as body temperature, heart rate, or respiratory rate, contactless systems are still under development. An interesting technological approach involves the use of thermal cameras for capturing vital data, as they can operate unobtrusively even in complete darkness and from a greater distance. Unfortunately, the section of measurements affects the recorded temperature; the absolute temperature is imprecise, and calibration is very complex and should be redone periodically. This paper presents a simple yet effective solution for enhancing thermal imaging. The solution is a temperature-controlled Peltier element with a feedback loop that provides an exact reference point in the desired temperature range. This might improve the detection of fever and infections and support further vital data recognition in humans and animals or condition monitoring in machines using thermal cameras.