Automation of reading liquid-in-glass thermometers

In this paper, the automation of calibration of liquid-in-glass thermometers (LiGTs) is discussed. Temperature readings are taken automatically with the use of a measuring system that consists of a standard calibration setup, a video camera and illumination, an image acquisition module and a computer that executes the algorithm for image processing and analysis. Once the reading of the temperature is extracted from the acquired image, this value can be passed to any other data processing program, which includes the comparison with the values from the reference thermometer and determination of correction and combined uncertainty. Data achieved in this way can be directly used to prepare the calibration certificate.