Fan Axin, Xu Tingfa, Wang Xi, Xu Chang, Zhang Yuhan
Key Laboratory of Photoelectronic Imaging Technology and System of Ministry of Education of China, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.
Beijing Institute of Technology Chongqing Innovation Center, Chongqing 401120, China.
Sensors (Basel). 2020 Dec 11;20(24):7120. doi: 10.3390/s20247120.
Polarized hyperspectral images can reflect the rich physicochemical characteristics of targets. Meanwhile, the contained plentiful information also brings great challenges to signal processing. Although compressive sensing theory provides a good idea for image processing, the simplified compression imaging system has difficulty in reconstructing full polarization information. Focused on this problem, we propose a two-step reconstruction method to handle polarization characteristics of different scales progressively. This paper uses a quarter-wave plate and a liquid crystal tunable filter to achieve full polarization compression and hyperspectral imaging. According to their numerical features, the Stokes parameters and their modulation coefficients are simultaneously scaled. The first Stokes parameter is reconstructed in the first step based on compressive sensing. Then, the last three Stokes parameters with similar order of magnitude are reconstructed in the second step based on previous results. The simulation results show that the two-step reconstruction method improves the reconstruction accuracy by 7.6 dB for the parameters that failed to be reconstructed by the non-optimized method, and reduces the reconstruction time by 8.25 h without losing the high accuracy obtained by the current optimization method. This feature scaling method provides a reference for the fast and high-quality reconstruction of physical quantities with obvious numerical differences.
偏振高光谱图像能够反映目标丰富的物理化学特征。同时,其所包含的大量信息也给信号处理带来了巨大挑战。尽管压缩感知理论为图像处理提供了一个很好的思路,但简化的压缩成像系统在重建全偏振信息方面存在困难。针对这一问题,我们提出了一种两步重建方法,逐步处理不同尺度的偏振特征。本文利用四分之一波片和液晶可调谐滤波器实现全偏振压缩和高光谱成像。根据它们的数值特征,对斯托克斯参数及其调制系数同时进行缩放。第一步基于压缩感知重建第一斯托克斯参数。然后,基于先前结果在第二步中重建具有相似数量级的后三个斯托克斯参数。仿真结果表明,对于未优化方法无法重建的参数,两步重建方法将重建精度提高了7.6 dB,并且在不损失当前优化方法所获得的高精度的情况下,将重建时间减少了8.25小时。这种特征缩放方法为快速、高质量重建具有明显数值差异的物理量提供了参考。