Fig. 1. Distortion correction principle diagram

Fig. 2. Image point coordinate sampling chart

Fig. 3. Principle diagram of two-dimensional distortion correction

Fig. 4. The law of refraction in vector form

Fig. 5. Point-by-point construction process

Fig. 6. Feature data point calculation process

Fig. 7. Optical layout diagram

Fig. 8. Field of view sampling strategy

Fig. 9. Image point data graph

Fig. 10. Freeform lens

Fig. 11. (a) Aspheric design architecture; (b) Freeform design architecture

Fig. 12. Freeform and aspherical contours in different directions

Fig. 13. Grid distortion

Fig. 14. (a) Relative illumination distribution of the original system; (b) Relative illumination distribution of the aspheric system; (c) Relative illumination distribution of the freeform surface system

Fig. 15. (a) Average MTF; (b) Average MTF distribution along Y=0°