Accurately measuring surface temperature is not difficult when the surface, the sensor, and air temperatures are similar, but it is challenging when the surface temperature is significantly different than air and sensor temperatures.
We tested three Infrared Thermocouple sensors (IRT’s) that had been used for two years in a greenhouse environment. The importance of the correction for sensor body temperature was also examined.
Pinnock, Derek R. and Bugbee, Bruce, "A Simple Test to Evaluate the Calibration Stability and Accuracy of Infrared Thermocouple Sensors" (2002). Techniques and Instruments. Paper 1.