Fig. 1. Discrete aperture detection framework for large-aperture segmented telescopes

Fig. 2. System low-order wavefront obtained based on discrete aperture and original wavefront. (a) Reconstructed wavefront; (b) original wavefront; (c) measurement residuals

Fig. 3. Validation system of segmented mirror test method. (a) Measurement light path; (b) experimental site

Fig. 4. Fine co-focus and co-phasing measurements based on the diffuse fringe. (a) Relationship between single actuator movement and visibility; (b) step difference and co-phasing error detection results

Fig. 5. Fringes before and after co-phasing adjustment. (a) Before adjustment; (b) after adjustment

Fig. 6. High precision step difference estimation based on broadband method. (a) Initial phase; (b) phase shift; (c) measurement result out of coherence length; (d) non-confocal state of discrete aperture detection for extended target; (e) confocal state of discrete aperture detection for extended target

Fig. 7. Photonics interferometry based step difference measurement results. (a) Large step size; (b) small step size

Fig. 8. Spectral testing based on discrete apertures. (a) Test site; (b) beam combining device; (c) beam combining spectrum measurement results; (d) contrast at different fields of view