Method for suppressing backward stray light in satellite ground laser communication system terminals considering multi-band polarization

In the process of suppressing backward stray light in the satellite ground laser communication system terminal, traditional stray light suppression methods ignore the local detail information of the target image during the suppression process, resulting in color distortion and edge discontinuity, which affects the imaging quality. The impact of different polarization states (0°, 45°, 90°) on the suppression effect of stray light varies significantly, and it is necessary to achieve stability and consistency of the suppression results under multi band polarization conditions. In response to this issue, researches were conducted on stray light suppression methods considering multi band polarization. By analyzing the optical structure of backward stray light involved in satellite ground laser communication terminals, a stray light diffusion function was constructed. The multi-band polarization degree was calculated and the image pixels were constrained under the influence of stray light. A binarization mask approach was employed to generate a mask image, thereby enabling the separation of stray light and diffuse reflected light. By fully accounting for the local detail information of the target, the light reflectance of stray light was calculated. A weighted regularization constraint was introduced to mitigate issues such as color distortion and edge discontinuity that might arise after stray light suppression. By combining the weighted regularization information completion method, the problem of suppressing stray light was transformed into an energy function minimization problem, thereby suppressing stray light. The experimental results show that this method is not affected by complex polarization environments. The suppressed light intensities at 0°, 45°, and 90° polarization states are 3.4×10⁴ W/m², 3.6×10⁴ W/m², and 4.0×10⁴ W/m², respectively, which are consistent with the ideal light intensity. It shows that this method has good suppression reliability.