High-accuracy contactless measurement method for measuring temperature of metal thermoforming mold

A high-accuracy contactless measurement method for measuring a temperature of a metal thermoforming mold, the method comprising steps of:

• (A):
• spraying a high temperature resistant coating on a metal to be measured, wherein the high temperature resistant coating is in a visible band of an infrared band, for determining a monitoring area on the high temperature resistant coating;
• (B):
• providing a temperature sensor, measuring a focal plane array (FPA) of the temperature sensor, obtaining an FPA operating temperature, determining a thermal radiation calibration regression coefficient based on the FPA operating temperature, and calibrating the temperature measured by the temperature sensor based on the thermal radiation calibration regression coefficient;
• (C):
• providing a contact temperature sensor, measuring the high temperature resistant coating to obtain a contact temperature value by using the contact temperature sensor, measuring the high temperature resistant coating to obtain a contactless temperature value by using the temperature sensor, and calculating the contactless temperature value to compensate an error of the contactless temperature value with the contact temperature value so as to obtain a calculated temperature value by taking the contact temperature value as a basic value;
• (D):
• setting a group of upper and lower limits of variations of the FPA operating temperature based on the FPA operating temperature, measuring the FPA to obtain a real-time FPA operating temperature and comparing the real-time FPA operating temperature with the FPA operating temperature obtained in Step (B), and returning to perform Step (B) to Step (D) when the real-time FPA operating temperature is greater than the upper limit of variations of the FPA operating temperature or smaller than the lower limit of variations of the FPA operating temperature;
• (E):
• setting a group of upper and lower thresholds of temperature, analyzing the calculated temperature value of the high temperature resistant coating in the monitoring area, and showing a warning sign on a monitoring display when an average value of the calculated temperature values of all of the analyzable high temperature resistant coatings is greater than the upper threshold of temperature or smaller than the lower threshold of temperature.