Fig. 1. BRDF measurement

Fig. 2. Magic black matting coating

Fig. 3. Detection system of BRDF

Fig. 4. Fitting data of BRDF

Fig. 5. Schematic diagram of the edge

Fig. 6. Dual telecentric coaxial optical detection of light-blocking ring edges

Fig. 7. Analysis of image quality. (a) Distortion; (b) MTF

Fig. 8. Flow diagram of the algorithm for edge recognition and edge thickness calculation based on grayscale image

Fig. 9. Test system data calibration. (a) Reticle; (b) Measurement accuracy

Fig. 10. Schematic of edge inspection

Fig. 11. Measurement of mask edge by imaging method

Fig. 12. Light-blocking ring edge thickness test data

Fig. 13. Schematic diagram of mask extinction ratio test

Fig. 14. Baffle design parameters

Fig. 15. Extinction ratio detection

Fig. 16. Stray light test in darkroom

Fig. 17. Stray light test data

Fig. 18. Stray light test at outfield

Fig. 19. Stargazing test data. (a) Accuracy of star sensor without stray light; (b) Accuracy of star sensor interfered by stray light using the baffle mentioned in this paper