Self-calibrating infrared thermometer for remote monitoring in cold climates

This paper presents a non-contact infrared thermometer capable of accurate measurements in cold climates. This is accomplished through the use of lens heaters to prevent frost forming and blocking infrared energy, and self-calibration to ensure that the thermal shock caused by the heater does not affect the measurement accuracy. Applications for this thermometer include the monitoring of railway tracks and roads to detect ice. The self-calibration technique reported is shown to successfully reduce measurement errors to within ±1°C compared with errors of greater than 20°C when the heater is cycled under normal operation. Results show that this method can be applied to any infrared thermometer utilizing a thermopile, regardless of optical geometry.