Multi-scale camouflage

The Canadian Forces were the first army to issue pixellated digital camouflage for all units with their disruptively patterned CADPAT, shown here in its 'Temperate Woodland' variant.

Digital camouflage are a type of camouflage patterns combining micro- and macro patterns, often with a pixellated look. The function is to provide military camouflage over a range of distances. While the term is usually associated with the pixelated look of many of the patterns, not all multiscale patterns are pixellated, and not all pixellated patterns combine micro- and macro patterns. The term is also used to refer to modern camouflage patterns created with the use of a computer, some of which do not conform to the stereotypical pixellated patterns.

History

Second world war 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 number of patterns 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.

Pixellated 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 pixels 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.

The CADPAT and MARPAT

The CADPAT and MARPAT patterns were thus 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, was delayed by 20 percent. 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.

Early digital patterns for uniforms

Further information: List of military clothing camouflage patterns

The Universal Camouflage Pattern provides insufficient contrast to disrupt a soldier's outline effectively.

By 2000, O'Neill's idea was combined with patterns like the German Flecktarn to create pixellated patterns like CADPAT or MARPAT. Battledress in digital camouflage patterns was first designed by the Canadian Forces. 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. However, the basis of "digital" camouflage was lost in tech reports; the design technique actually has three purposes: (1) to add high spatial frequency texture components that add concealment at closer ranges, (2) to modify visual processing of edges, and (3) to produce intermediate colours by a dithering effect.

"Digitizing" a pattern does not of itself improve performance; the design process is actually more complex, and involves colour and contrast as well as overall disruptive effect of specific pattern geometry. 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".