An iterative algorithm to improve infrared thermographic systems’ accuracy in temperature field measurement of aluminum alloys

Accurate real-time measurement of temperature is vital for ensuring successful production of aluminum alloy parts. As an excellent approach to real-time measurement of aluminum alloys’ temperature field, infrared thermal imaging systems enable non-contact, fast-response measurement. However, the emissivity of aluminum alloys varies by temperature, making accurate measurements by infrared thermographic systems unavailable. For this reason, an emissivity iterative algorithm is proposed in this paper. The emissivity-temperature curves of aluminum alloys are obtained and used for the correction of the temperature field. The algorithm helps infrared thermal imaging systems reduce their dependency on emissivity and thus realizes a precise temperature field measurement for aluminum alloy. To validate this model, we conduct experiments to measure the temperature field of uniformly heated aluminum alloys, and of friction stir welding. Results of the experiments show this model can effectively improve the accuracy of infrared thermographic systems for measuring the temperature field of aluminum alloys.