Impact of Waveband on Target-to-Background Contrast of Camouflage

The purpose of military camouflage is to make an object hard to see, or to confuse a hostile observer as to its true nature. Perfect camouflage would do this by making itself invisible against its surroundings. Currently, the best camouflage attempts to make the target appear to be a natural part of the background. An imperfect but still very useful metric of this similarity between target and background is the at-range contrast difference between them, and the smaller that is, the harder it is to discern the camouflaged object and the longer it takes to determine its true nature. The intrinsic contrast difference in the reflective wavebands (i.e., visible through short wave infrared), is a function of the spectral nature of the scene illumination and the spectral reflectivity of the camouflage and background. Until recently, military camouflages have been typically designed to work best in the visible band against one of the generic background types such as woodland, desert, arctic, etc., without significant attention paid to performance against a different background, type of scene illumination, or different waveband. This paper documents an investigation into the dependence of the contrast difference behavior of camouflage as a function of waveband, background, and scene illumination using battle dress uniforms (BDU) as material.