林地型伪装网热红外发射率取值分析

Decision of the Thermal IR Emissivity of Woodland Camouflage Net

在晴朗无风的白天及夜间考察了不同发射率伪装网装饰布（热红外发射率从0．63～0．94）与樟树树冠的辐射温差，并参照可见光变形迷彩设计理论分析了林地型伪装网中间色斑块的发射率取值范围。实验表明，传统林地型伪装网在热红外波段不能满足昼夜与林地背景融合的要求。林地型伪装网要满足强目照下热红外伪装的要求，中间色斑块的发射率必须小于0．63；要满足夜间热红外伪装的要求，中间色斑块的发射率不小于0．83。综合采用发射率可变涂料、降低太阳能吸收率、增强网面对流换热等技术手段可改善林地型伪装网与背景的昼夜兼容能力。

The apparent temperature difference between camouflage net cloth and camphor trees were calculated from the thermal IR images,which were shot under cloudless and windless weather. The camouflage cloth has different thermal IR emissivity from 0.63 to 0.94. Analogizing to the visible distort pattern design theory,the appropriate emissivity of mid-brightness camouflage cloth is discussed. The traditional woodland camouflage net can not get ideal efficiency in daytime and nighttime simultaneously. The thermal IR emissivity of mid-brightness camouflage cloth must be less than 0.63 to get effective camouflage under sunshine. But it requests emissivity larger than 0.83 to fulfill the camou- flage efficiency in nighttime. The camouflage efficiency compatibility in daytime and nighttime may be improved by camouflage cloth of alterable emissivity, of low solar energy absorptivity and of better convection heat exchange.