Fig. 1. Optical path of refractive Offner compensator null test

Fig. 2. Three different structural forms of Offner compensator. (a) Structural form 1; (b) structural form 2; (c) structural form 3

Fig. 3. Distribution of original data points in structural parameter coordinate system. (a) Data point distribution diagram of structural form 1; (b) data point distribution diagram of structural form 2; (c) data point distribution diagram of structural form 3

Fig. 4. Spline interpolation surfaces with different structural forms. (a) Scattered data point distribution map of structural form 1 and its interpolation surface; (b) scattered data point distribution map of structural form 2 and its interpolation surface; (c) scattered data point distribution map of structural form 3 and its interpolation surface

Fig. 5. Distribution of randomly selected data points in parameter space. (a) Selection diagram of simulation verification data points; (b) comparison between actual verification points and interpolation residuals

Fig. 6. References of design results of parabolic Offner compensator. (a) Reference Ⅰ; (b) referenceⅡ