Digital camouflage

Principles

Digital camouflage is based on three principles:

Multi-scale patterns

The idea of a multi-scale pattern extends back to the interwar period in Europe. Early printed patterns of camouflage, like the 1929 Italian telo mimetico has larger and smaller elements in the patterns, but it was not until German experiments during the Second World War that true complex multi-scale patterns were developed. Traditional single scale patterns work well in their optimal range from the observer, however an observer too close or too far away will not see the pattern optimally. Nature itself is very often fractal, where plants and rock formations exhibit similar patterns across several magnitudes of scale. The idea behind multi scale patterns is both to mimic the self-similarity of nature, and also to offer scale invariant camouflage that works at close range as well as at traditional combat range.

European experiments

The scale of camouflage patterns has an obvious effect on their use. Large structures need larger patterns than smaller vehicles and single soldiers to disrupt their shape. At the same time, large patterns are more effective from afar, while small scale patterns work better up close.

During the Second World War, Johann Georg Otto Schick designed a series of patterns such as Platanenmuster (plane tree) and erbsenmuster (pea pattern) for the Waffen-SS, combining micro- and macro-patterns in one scheme. The German Army developed the idea further in the 1970s into Flecktarn, which combines smaller shapes with dithering; this softens the edges of the large scale pattern, making the underlying objects harder to discern.

Pixel-like shapes pre-date computer-aided design by many years, already being used in Soviet Union experiments with camouflage patterns, such as "TTsMKK" developed in 1944 or 1945. The pattern uses areas of olive green, sand, and black running together in broken patches at a range of scales.

Tank camouflage in the 1970s

In the 1970s, US Army officer Timothy R. O'Neill suggested that patterns consisting of square blocks of colour would provide camouflage that was more effective than traditional patches of brown and green. Large patches of colour worked well at long range, and small patches at short range, but neither scheme worked well at all ranges. O'Neill's idea was to create a complex pattern of small (2 inch) squares, in modern terms pixels, so that at short range an observer would see a woodland pattern, while at long range the small pixels would merge into larger patches, giving the appearance of a woodland pattern at a larger scale also.

CADPAT and MARPAT

By 2000, O'Neill's idea was combined with patterns like the German Flecktarn to create pixellated patterns for battledress like the Canadian Forces' CADPAT, issued in 2002, and then the US Marines' MARPAT, rolled out between 2002 and 2004. The CADPAT and MARPAT patterns were somewhat self-similar (in the manner of fractals and patterns in nature such as vegetation), being designed to work at two different scales; a genuinely fractal pattern would be statistically similar at all scales. A target camouflaged with MARPAT takes about 2.5 times longer to detect than older NATO camouflage which worked at only one scale, while recognition, which begins after detection, took 20 percent longer than with older camouflage. Fractal-like patterns work because the human visual system efficiently discriminates images which have different fractal dimension or other second-order statistics like Fourier spatial amplitude spectra; objects simply appear to 'pop out' from the background. O'Neill helped the Marine Corps to develop first a digital pattern for vehicles, then fabric for uniforms, which had two colour schemes, one designed for woodland, one for desert.

Digital patterns for uniforms

The "digital" refers to the coordinates of the pattern, which are digitally defined. The term is also used of computer generated patterns like the non-pixellated Multicam and the Italian fractal Vegetato pattern.

According to the patent for MARPAT, pixellation does not in itself contribute to the camouflaging effect. The pixellated style, however, simplifies design and eases printing on fabric, compared to traditional patterns. While digital patterns are becoming widespread, critics maintain that the pixellated look is a question of fashion rather than function.

"Digitizing" a pattern does not of itself improve performance; the design process involves trading-off different factors, including colour, contrast and overall disruptive effect. A failure to consider all elements of pattern design tends to result in poor results. The US Army's Universal Camouflage Pattern (UCP), for example, performed poorly because of low pattern contrast ("isoluminance"—beyond very close range, the design looks like a field of solid light grey, failing to disrupt an object's outlines) and arbitrary colour selection, neither of which could be saved by quantizing (digitizing) the pattern geometry. According to the New York Times, O'Neill was "dismayed" when the U.S. Army issued digital camouflage uniforms in only one colour range "to hide soldiers anywhere in the world, from sand dunes to jungles. 'I had 10 cat fits and a dog fit'" as he considered that a single 'universal' scheme would be "useless everywhere". In 2014 the U.S. Army tested new patterns to replace the single UCP for the same uniform, including woodland, semi-woodland and arid variants.