Spectral reflectance and transmission properties of a multi-layered camouflage net: Comparison with natural birch leaves and mathematical models

Abstract

With improved specifications and capabilities of modern sensors and detectors, concealment is an increasingly challenging endeavor. Concealment from modern sensors requires advanced camouflage material that can provide low background contrast over a wide range of spectral wavelengths. Multi-layer material (i.e. textile fibers) allow for advantageous camouflage abilities such as improved heat transfer and modification of spectral signatures. In this study, we investigate the effect of multiple layers on the reflectance properties of a camouflage net. Camouflage nets provide protection against visual, thermal and radar threats, and can be tailored to offer effective concealment in various natural backgrounds and climate zones. By utilizing a simple mathematic model, we predict multi-layered reflectance properties of the camouflage net from single-layer reflectance data. The model is in good agreement with measurement data for multi-layer net material, and the materials in the study behaves similar to partly transmitting leaves. We also find that 2-3 layers of the materials is sufficient to hinder reflectance contributions from the background. At certain wavelengths, the required number of layers is even lower and reveals that the transmission and reflectance are wavelength dependent.