Snapshot hyperspectral polarization imaging technology combines spectral imaging and polarization imaging, allowing for the simultaneous acquisition of hyperspectral, polarization, and spatial information. This forms a four-dimensional data cube of the target, expanding the dimensions of target information perception. The system finds wide applications in marine environment monitoring, earth remote sensing, forest resource exploration, military reconnaissance, and search and rescue operations. However, current hyperspectral polarization imaging systems, developed by various research institutions, typically use a fixed-focus system, which struggles to integrate high polarization imaging resolution with high spectral resolution. Improving spectral resolution often limits polarization imaging resolution, resulting in unclear target imaging. In this paper, we propose an integrated imaging solution based on spatial dimension coding. The design maintains constant spectral resolution while improving polarization imaging resolution when switching between short and long focal lengths. The system enables wide-field scanning in the short-focus state and high-resolution imaging in the long-focus state, broadening the application scope of hyperspectral polarization imaging technology.

First, the initial structural parameters of the front zoom objective are determined by establishing a focal distribution model for the reverse telephoto zoom objective. An ultra-long rear intercept zoom objective with a reverse telephoto coefficient of 2.5 is designed to address the issue of optical path occlusion. Next, the coupling relationship between stop position and uniformity of image surface illuminance is analyzed, and the optimal stop position is determined to improve the accuracy of polarization information acquisition at the edges of the system’s field of view. In addition, a digital micromirror device (DMD), relay mirror, imaging mirror, micro polarizer array (MPA), and spectral resolution are proposed to improve both the system’s spectral resolution and pixel matching accuracy. Based on this analysis, a snapshot hyperspectral polarization two-speed zoom imaging optical system is designed, and its imaging quality is evaluated. Finally, a verification experiment is conducted to demonstrate the feasibility of the proposed scheme.

After completing the overall optical design, at a Nyquist frequency of 144 lp/mm, the modulation transfer function (MTF) of the system across the full focal range, field of view, and wavelength band, along both the meridional and sagittal planes, exceeds 0.205 (Fig. 7), indicating excellent imaging quality. When switching between short and long focal lengths, the spectral resolution remains stable (Fig. 8). Moreover, in the 400?650 nm band, the spectral resolution is better than 1.06 nm, providing high spectral fidelity. The degree of linear polarization (DOLP) error test reveals that the DOLP error is less than 4.8%, confirming strong polarization retention (Table 5). The resolution plate imaging experiment (Fig. 11) demonstrates improved polarization imaging resolution after switching focal lengths, with the short-focus state achieving 4.36 mrad and the long-focus state achieving 1.39 mrad. Spectral reconstruction accuracy was further verified through imaging experiments with color pens (Fig. 12). The system’s measured reflectance was compared with that of a commercial spectrometer, showing that the reflectance characteristic peaks closely matched, confirming high spectral reconstruction accuracy and the system’s strong spectral resolution. Finally, field tests were conducted, where the system successfully imaged a moving car. From the DOLP images, we can clearly distinguish the front and rear of the vehicles (Fig. 13), verifying the system’s ability to capture spectral polarization information and effectively image dynamic targets under natural lighting conditions.

In this paper, we propose an integrated spectral polarization imaging scheme based on spatial dimension coding. Utilizing a two-speed zoom mechanism, the system achieves a triple zoom effect while maintaining strong imaging performance. When switching from the short-focus to the long-focus state, the spectral resolution remains unchanged, while the polarization imaging resolution is improved. Within the working spectrum of 400?650 nm, the spectral resolution exceeds 1.06 nm. The feasibility of the proposed scheme is validated through the setup of an experimental verification system and field experiments. The designed snapshot hyperspectral polarization two-speed zoom imaging optical system balances both high polarization imaging resolution and high spectral resolution. It is capable of adapting to fast-moving targets, quickly detecting, locking onto, and tracking them in real time. This enables the acquisition of a data cube encompassing the target’s spatial, spectral, and polarization information, supporting target detection and recognition. The system has significant theoretical and practical implications for the future development and modeling of airborne snapshot spectral polarization imaging system.