Fig. 1. Four-wavelength detection imaging principle

Fig. 2. Spectral response of four-wavelength imaging thermometer

Fig. 3. Design scheme of four-wavelength imaging thermometer

Fig. 4. Optical objective lens design drawing

Fig. 5. Four-color filter design form

Fig. 6. Software flow chart of four-wavelength imaging thermometer

Fig. 7. Principle of high temperature measurement experiment of imaging thermometer

Fig. 8. Visible image and near infrared image of target

Fig. 9. Comparison of test results between four-wavelength thermometer and thermocouple