Abstract:Imaging spectrum technology can obtain the image and spectral characteristics of the target at the same time, and it is easy to identify the traditional camouflage materials whose spectrum are different from the background spectrum. In recent years, imaging spectrum has been developed rapidly, which has experienced the leap from multispectral technology to hyperspectral technology. Owing to the application of ISR UAV technology in various countries, hyperspectral sensors are expanded from spaceborne to airborne, which can identify military camouflage targets in a closer range, and pose a huge challenge to the survival ability of military targets with important value. At present, the main design idea of hyperspectral camouflage materials is to composite materials with similar color and spectral reflection characteristics (within the detection range of sensors), so as to achieve “the same color and spectrum” with the environmental background to avoid the high spectrum reconnaissance. Green vegetation is the most common camouflage background, and it is also the spectral simulation object of most researches in this field. Its spectral reflection curve has four main characteristics in the visible near-infrared range: “green peak”, “red edge”, “near-infrared plateau” and “water absorption band”, assign to leaf tissue structure, chlorophyll and water. The photothermal stability of chlorophyll in vitro is poor, which cannot be directly used as camouflage material, so it is one of the current researches focuses on finding and synthesizing molecules with good stability, chlorophyll-like structure and spectrum. In addition, chrome green and cobalt green are commonly used camouflage pigments, which have spectral reflection characteristics similar to green vegetation, like “green peak”, “red edge” and “near-infrared plateau”. Researchers composited them with superabsorbent fillers to introduce “water absorption peak”, roughly simulating the reflection spectrum of green vegetation, but there are still some problems to be solved in order to achieve accurate simulation. Based on the Vis-NIR reflection spectra of green vegetation, this paper elucidated the material selection, which simulating spectrum properties of green vegetation in the visible and near-infrared region respectively, introduced the problems existing in the accurate simulation of the vegetation spectra, and the research work of improving the spectral similarity and weather ability through modification and composition. The prospects for the future developments are also discussed.
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