Bionic membrane simulating solar spectrum reflection characteristics of natural leaf

Hyperspectral imaging is becoming an important detection method, which can identify the subtle differences between the reflection spectra of a target and its background. Considering that vegetation is one of the most important backgrounds, a bionic membrane containing hygroscopic material and chromium sesquioxide (Cr2O3) pigment was prepared to counter the hyperspectral detection through simulating the solar spectrum reflectance of natural leaf. The effects of water and Cr2O3 contents on the reflectance of the bionic membrane were discussed, and the absorption and scattering coefficients of the bionic membrane were calculated via a four-flux model to elucidate its reflection mechanism. Based on the obtained absorption and scattering coefficients, the reflectances of the bionic membranes (with a volume fraction of water in the range of 9.75-51.92% during the day time) containing different volume fraction of Cr2O3 (fc) were calculated through the four-flux model. Besides, a military specification of USA was used as the spectrum requirement of the bionic membrane in our work to determine an appropriate Cr2O3 content. It was found that when fc is 1.61%, the reflection spectra of the 3 mm thick bionic membranes can not only meet the military specification but also become opaque, which are capable to camouflage a target.