## 5 Discussion and Prospects  
Recently, significant progress has been made regarding hyperspectral camouflage materials and technologies. Through vigorous research, a theoretical system of hyperspectral camouflage has been gradually formed, which has greatly improved the effectiveness of military camouflage. The future development trends of vegetation-imitating hyperspectral camouflage materials and technologies are shown below:  
* Improving the bionic camouflage technology  
The inorganic or organic pigments used in traditional camouflage materials are completely different from the biological pigments in green vegetation, and they can be easily identified by hyperspectral detection. Thus, to improve the camouflage performance of the target, we must solve the shortcomings of the existing traditional bionic camouflage technology. For example, pigments can be compounded, doped, or added with chlorophyll-like spectral fillers (e.g., phthalocyanine compounds) to accurately simulate important spectral features, such as green reflection peaks and red edges. In addition, the reflection characteristics of green vegetation are closely related to their water content. However, the existing camouflage materials contain little to no water, making it difficult to accurately simulate the moisture characteristic absorption peak of the vegetation background. Therefore, the design and preparation of bionic camouflage materials must be focused on studying their moisture absorption and water-retention mechanism. In this way, these materials can have a water-retention effect similar to plants, and they can show spectral characteristics that are basically consistent with the vegetation background, achieving effective resistance against hyperspectral detection;
* Improving the performances of leaf-simulating camouflage materials  
At the technical level of hyperspectral camouflage, the biggest challenge is how to design a suitable material system that can achieve the camouflage function of hyperspectral camouflage materials. First, to achieve the hyperspectral camouflage effect, the primary problem is to design and prepare a bionic material that can be preserved for a long time. Second, achieving the hyperspectral camouflage performance of materials is another key  
Figure 12: 1 Three-ayer structured metamaterials inspired by the spectral characteristics of natural leaves in the solar and infrared bands [101].  
issue. At the application level of hyperspectral camouflage, leaf bionic camouflage materials must not only meet the performance requirements of hyperspectral camouflage but also account for the comprehensive performance under service conditions and meet certain use performance indicators. At the current stage, the above issue is mainly reflected in how to improve the usability and reliability of materials in actual service environments and develop a material system with excellent hyperspectral camouflage performance and comprehensive capabilities.  
[PERSON] organized and compiled this article. [PERSON], [PERSON] and [PERSON] provided the ideas and references. All authors contributed to the article and approved the submitted version. All authors have read and agreed to the published version of the manuscript.  
This work was financially supported by the National Natural Science Foundation of China (51875249), the Jilin Engineering Normal University PhD startup foundation (BSKJ201902), the Education Department of Jilin Province (JIKH20230223 KJ), and the Science and Technology Development Plan Project of Jilin Province (YDZJ202201 ZYTS317).  
Not applicable.  
The authors declare no conflict of interest.