Centroid-Preserving Dynamic Star Image Deblurring for Remote Sensing Satellite Attitude Measurement via Physics-Guided Bi-Level Optimization

Star trackers commonly suffer from star point trailing during stellar imaging under dynamic observation conditions. Traditional non-blind deconvolution methods rely on a known Point Spread Function (PSF), whereas blind deconvolution approaches are plagued by a complex solution space and a high tendency to fall into local optima. These drawbacks make it difficult to meet the requirements of high-precision star centroid extraction. To address these challenges, this paper proposes a novel blind restoration method based on physical model guidance and alternating iterative optimization. Firstly, the parameters of the blurred PSF are blindly estimated using image moment analysis, and a motion blur physical model with controllable direction and length is constructed. Secondly, the iterative ideal physical model is embedded as a strong prior into curvature filtering to achieve guided denoising, which effectively suppresses noise while maintaining the original trailing structure. Finally, a dual-layer alternating optimization framework grounded in the ideal physical model was developed. The inner layer employs the Richardson–Lucy (RL) algorithm integrated with intelligent convergence criteria for high-precision image restoration. The outer layer utilizes a gradient descent algorithm equipped with a confidence-based full step-length strategy to optimize PSF parameters. This architecture establishes a self-correcting closed-loop mechanism characterized by iterative image restoration–model refinement cycles. The simulation results demonstrate that the proposed method generally maintains the star centroiding error below 0.1 pixel without prior knowledge of the PSF, with a maximum observed error of 0.105 pixel under the most challenging high-background condition. Its performance is close to non-blind restoration and significantly outperforms traditional blind deconvolution algorithms. It provides an effective solution for high-precision star centroiding under dynamic conditions.