In-situ surface measurement of large-aperture convex aspherical optics based on closed-loop multi-view stitching deflectometry

Large-aperture convex aspherical optics are key components in advanced optical systems, where accurate surface figure measurement is essential for guaranteeing system performance. However, due to the large-aperture and convex geometric characteristics, reflected rays exhibit strong divergence, which makes in-situ surface figure measurement of large-aperture convex aspherical optics extremely challenging during fabrication and polishing. To address this issue, this paper proposes an in-situ measurement method based on closed-loop multi-view stitching deflectometry for large-aperture convex aspherical optics. Specifically, a high-precision closed-loop optimization model is first established to determine the relative poses among multiple cameras and the screen. Subsequently, a synchronized stitching algorithm is employed to compute stitching coefficients and compensate for inconsistencies among sub-apertures, enabling accurate surface reconstruction. Finally, an aspherical surface registration method is used to calculate the surface figure. Experimental results from a convex hyperbolic aspherical surface with a measured aperture of approximately 420 mm × 420 mm show that the proposed method achieves sub-micrometer level RMS accuracy, providing an efficient and cost-effective solution for the in-situ measurement of large-aperture convex aspherical optics.