Fig. 1. Design rendering of infrared integrating sphere

Fig. 2. Diagram of overall controlling plan

Fig. 3. Structural schematic of infrared radiation unit. (a) Overall view; (b) sectional view

Fig. 4. Uniform-light effect of parent integrating sphere

Fig. 5. Schematic of electric aperture

Fig. 6. Measurement result of angular uniformity in vertical plane

Fig. 7. Measurement of planar uniformity. (a) Schematic; (b) measurement result

Fig. 8. Output spectral radiance of parent integrating sphere at different radiation medium temperatures

Fig. 9. Output spectral radiance of parent integrating sphere in four magnitude levels

Fig. 10. Parent integrating sphere spontaneous radiation and blackbody radiation. (a) Simulated value, Tsp2=155 K; (b) measured value, Tsp2=298 K

Fig. 11. Ratio of background radiation to output radiance when temperatures of parent integrating sphere are 155 K and 298 K, respectively

Fig. 12. Temperature control accuracy of infrared radiation medium. (a) Effect of ΔTL on instability of spectral radiant flux; (b) effect of ΔTL on radiance output instability of radiation source system

Fig. 13. Effect of temperature control accuracy of radiation source system on output spectral radiance

Fig. 14. Data of platinum resistance temperature sensor within fifteen minutes

Fig. 15. Test results of instability