空间调制型偏振成像的滤波器带宽优化方法研究

Optimization of optimal filter bandwidth for spatially modulated full polarization imaging

针对空间调制型全偏振成像系统在不同目标场景下成像效果不稳定的问题,使其在多目标场景均能保持最佳性能,提出了一种基于仿真干涉水印条纹的滤波器带宽优化计算方法,实现了对系统成像透镜的选型理论指导。通过在强度图像上叠加不同稀疏程度仿真干涉水印条纹的二维正弦函数得到仿真干涉图像,应用快速傅里叶变换和频域低通滤波算法对仿真干涉图解调得到全偏振图像,再对与强度图像结构相似度最高的偏振图像进行求解。提出了基于改进粒子群优化算法的最优滤波器带宽计算方法,通过引入疫苗提取选择策略和模拟退火机制实现了最优滤波器带宽的自适应选取,再结合不同目标场景下选定的图像分辨率、入射光波长及Savart偏光镜单束光偏移量等系统参数,计算得到成像透镜最优焦距,从而完成理论选型。实验部分对比分析了基于最优滤波器带宽选型与传统的自行经验选型的空间调制型全偏振成像系统稳定性,实验结果表明,基于最优滤波器带宽搭建的空间调制型全偏振成像系统性能较好,所提出的基于最优滤波器带宽选型相比于自行经验选型的频谱图反演面积增大4.16倍、图像结构相似度提高了63%,显著提高了系统的偏振成像质量。

To address the issue of unstable imaging performance of spatially modulated fully polarized imaging systems in different target scenes,this paper proposes a method for optimizing filter bandwidth calculation based on simulated interference watermark fringes.This method aims to ensure that the system maintains optimal performance across various target scenarios and provides theoretical guidance for selecting system imaging lenses.The approach involves generating simulated interference images by superimposing two-dimensional sine functions of varying sparsity,which represent simulated interference watermark fringes,onto intensity images.The fast Fourier transform and the frequency domain low-pass filtering algorithm are used to demodulate the simulated interference diagram,producing the total polarization image.The polarization image with the highest structural similarity to the intensity image is selected for further analysis.Additionally,an optimal filter bandwidth calculation method based on improved particle swarm optimization algorithm is proposed.The adaptive selection of the optimal filter bandwidth is achieved by introducing a vaccine extraction selection strategy and a simulated annealing mechanism.Combined with the selected image resolution,incident light wavelength and Savart polarizer single beam light offset in different target scenes,the optimal focal length of the imaging lens was calculated,and the theoretical selection was completed.In the experimental section,the stability of the spatial modulation-based full-polarization imaging system,built using the optimal filter bandwidth selection,is compared with that of the traditional experience-based selection.The experimental results show that the spatial modulation total polarization imaging system based on the optimal filter bandwidth has better performance.The area of spectral graph inversion is increased by 4.16 times and the similarity of the image structure based on the optimal filter bandwidth selection is improved by 63%compared with the self-empirical selection,which significantly improves the polarization imaging quality of the system.