Fig. 1. Principle of spectrum split based on CVF

Fig. 2. Lightpath diagram of CVF type spectroradiometer

Fig. 3. Blackbody emissivity

Fig. 4. Diagram of experimental system

Fig. 5. Flow diagram of data processing

Fig. 6. Spectra of blackbody at different temperatures. (a) Band of InSb detector; (b) band of MCT detector

Fig. 7. Responsibility curves of blackbody at 200 ℃. (a) Band of InSb detector; (b) band of MCT detector

Fig. 8. Gas transmittance curves. (a) CO₂; (b) H₂O

Fig. 9. Comparison of responsibility curves before and after atmospheric absorption rejection. (a) Before rejection; (b) after rejection

Fig. 10. Measured responsibility at 4.515 μm and 11.560 μm at different calibration temperatures

Fig. 11. Comparison of measured and theoretical radiance of blackbody at 200 ℃

Fig. 12. Relative errors in radiometric calibrations at different blackbody temperatures. (a) Band of InSb detector; (b) band of MCT detector