Misalignment-induced aberration compensation technique based on feature extraction and optimization of spot images at an arbitrary single field point.

Off-axis telescopes in operational states are susceptible to environmental variations and mechanical vibrations, which deviate the secondary mirror (SM) from its nominal positions and induce misalignment aberrations. Existing compensation techniques for SM misalignment-induced aberrations of off-axis telescopes typically rely on fixed multi-field points wavefront sensing data or spot images to solve for misalignment restoration solutions. These methods suffer from limitations such as poor environmental adaptability, inflexible field-of-view configuration, and high computational costs for achieving high-precision misalignment restoration solutions. To address this, this paper proposes an aberration compensation technique based on feature extraction and optimization from arbitrary single field point spot images. It utilizes unbiased finite impulse response (UFIR) moments to extract spot image features and combines them with the differential evolution (DE) nonlinear optimization algorithm to find equivalent misalignments, thereby achieving system aberration compensation. Simulation verifies the feasibility of this method and compares its performance with typical image moment approaches. The influence of atmospheric turbulence on the presented method is also analyzed. Finally, physical experiments are conducted on an experimental platform for further validation. This technique compensates for aberrations using only arbitrary single field point spot images, without requiring multiple field points wavefront or spot data, nor precise determination of actual misalignments. It simplifies the misalignment-induced aberration compensation process and provides a reference for subsequent engineering applications.