Comparing temperature measurement using infrared line scanners and the wedge method

Temperature measurement based on infrared radiation depends on correctly adjusted emissivity. However, emissivity configuration is not an easy task because emissivity is not normally known with precision, it is influenced by radiation reflections, and can also change with the temperature. The wedge method is a temperature measurement method which assures correct correct emissivity configuration using an infrared camera to take images of a wedge region. Within the wedge, a virtually closed cavity for radiation is created. Although this method out-performs traditional infrared measurement, no comparison has yet been carried out under real industrial conditions which would provide information about emissivity variations. This work compares the temperature measurement acquired from a calibrated infrared line scanner, and the temperature measurement using an infrared camera and the wedge method. Conclusions provide recommendations and guidelines for technicians interested in temperature measurement.