New method of two-color calibration and one-color measurement for real-time inspection of temperature field

摘要

Based on the research of a colorimetric method with tow RI images, a new method of two-color calibration and one-color measurement for real-time inspection of welding temperature field was developed, which can not only eliminate disadvantages of one-color measuring method, such as dependence of the measured temperature on the distance of object and the emissivity of object and the parameters of the measurement system, but also overcomes disadvantages of two-color measuring method, such as the low speed and sensitivity on the noise in the measurement. The method is applied successfully in welding temperature field measurement, the measuring time is less than 0.5 second per temperature field and the error of measurements is within 30 degrees C. Weld shape control is another important application of the developed method. Using the width of isotherm from welding temperature field as input and welding current as control parameter, a penetration control system for TIG weld was installed. Experiments proved that the even penetration be obtained under very unstable weld condition.