Overview of the history of the development of camouflage uniforms and its influence on the current state of camouflage

Tikhanychev Oleg Vasilyevich ORCID: 0000-0003-4759-2931 PhD in Technical Science Deputy Head of the Department of Advanced Development Management, "Technoserv Group" 13 Yunosti str., Moscow, 111395, Russia to.technoserv@gmail.com Other publications by this author

Tikhanycheva Evgeniya Olegovna ORCID: 0000-0003-0091-0779 Employee, Moscow Museum of Modern Art 25 Petrovka str., Moscow, 125009, Russia etikhanycheva@mail.ru Other publications by this author

1. Introduction

An analysis of the development of the processes of providing individual elements of military operations shows that in the early stages of the development of combat operations management, it was carried out on the basis of visual information, for which special elements of visualization of the combat situation were used, distinguishable from afar: pennants, banners, equipment details, for example, colored plumes on helmets. In the Middle Ages, recognition was one of the functions of a colored cape worn over armor – a surcoat. With the increase in the size of the battlefield, it was necessary to implement more visual visualization options: the introduction of colored versions of military uniforms and even horse suits for different regiments, providing visible differences between units, both of the opposing armies and within each of them, including units of various branches of the armed forces. The ordering of the color differentiation of uniforms became possible with the advent of regular armies and with the obligatory condition of a developed chemical industry. The Roman army, for example, was regular, but the rules of uniform dress were not followed precisely for economic reasons ^[1].

Once again, we recall that objectively, the need to use solutions for the color division of the uniform was determined by the way of managing combat operations, in which the assessment of the current situation was carried out exclusively visually ^[2]. According to historical data, the primacy in the centralized implementation of the approach to the color differentiation of field uniforms can be considered to belong to our country – for the first time an intentional color difference appeared in the uniforms of the Streltsy regiments under Ivan the Terrible, during the military reform of 1549-1560. In the same historical period, European armies, consisting mainly of mercenary units, still fought in casual clothes, distinguishing the enemy only by the colored ribbons on their uniforms and hats. With this in mind, according to one version, the word "gang" in many European languages came from the German das B a nd (ribbon): from the colored ribbons that the mercenary groups used to designate themselves at that time. And the color differentiation of field uniforms appeared in European armies only at the beginning of the XVII century.

With the development of military equipment, the emergence and mass introduction of effective long-range and rapid-fire weapons, in full accordance with the laws of dialectics, the principles of organizing combat operations have changed. Already with the advent of the first samples of firearms, special techniques for its use appeared, the implementation of which required the masking of shooters. An example is the uniforms of Russian huntsmen of the XVIII century, made in soft colors and devoid of distinctive components, as well as the refusal of huntsmen to act in formation and the use of improvised means by the latter. Experts in this context often refer to Suvorov's instructions, which instruct rangers to use torn tree branches with leaves for camouflage on the battlefield.

Since about the middle of the XIX century, these factors, having significantly increased the loss of personnel from targeted fire, required the adoption of new technical solutions regarding the protection of military personnel, changes in the functions implemented by military uniforms from identification to ensuring secrecy. With the development of weapons, the importance of camouflage grew: with the advent of aviation, it was necessary to disguise from above, with an increase in the range of weapons – at a previously safe distance from the front line. With the development of radio communications, masking on the air was required. With the transition to the era of large armies, measures to ensure secrecy began to be divided into tactical, carried out on the battlefield, and strategic, carried out to mislead the enemy at a higher level.

With the spread of combat operations to different physical environments and virtual space, new requirements have emerged, both in terms of ranges and environments of camouflage, and in terms of its fullness, both in real and in the information space.

But all this does not reduce the importance of measures to ensure secrecy in the visible part of the optical range, implemented both by bringing the color of items of clothing, equipment and military equipment to the background of the surrounding area, and by optical and physical distortion of the contours of objects ^[3].

2. Materials and methods

The main research methods used are analysis and synthesis. Based on the analysis of the features of previously used and currently existing methods of disguising personnel, possible directions of their development are synthesized. The use of a systematic approach that takes into account disguise as part of the engineering support of combat operations made it possible to consider this issue comprehensively.

As a limitation, it is accepted that the research is conducted in the field of tactical camouflage of military personnel, without addressing the issues of disinformation and misleading the enemy used at higher levels.

The source base of the research was made up of scientific and historical, managerial, organizational and technical documents that are in the public domain.

3. Discussion

3.1. The beginning of the development of protective equipment

The analysis of historical documents shows that the field military uniform began to be sewn from a protective fabric in the late XIX – early XX century. The first documentary mention of the use of khaki uniforms (English - khaki, from the Persian "haq" - dusty) dates back to 1867-68. The protective coloration of the uniforms was used for auxiliary units of the British Army in India. By the beginning of the Anglo-Boer War of 1899-1902, the main units of the British army had already been transferred to a new field uniform, replacing the red coats, which ensured a noticeable reduction in losses from small arms. Thus, the principle of using protective equipment confirmed its effectiveness on the battlefield, but the neglect of its use in the era of rapid-fire and long-range weapons was expensive for the troops. Russian Russian infantry, dressed in white tunics, suffered unjustifiably high losses from enemy small arms fire during the Russo-Japanese War. To reduce losses, soldiers of the Russian Imperial Army specially put on old tunics that had lost their whiteness before the battle, which in some cases was even regulated by the instructions of the command ^[4]. Taking into account the experience of combat operations, before the First World War, the protective color uniform was adopted for supply by almost all the leading armies of the world.

But simply approximating the color of field uniforms to the color of the surrounding area did not fully solve the problem of countering the detection of military personnel. The way out, as it often happens, was suggested by nature – a complex coloring that blurs the contours of objects, concealing their real dimensions, geometric center, individual details and direction of movement, making it difficult to recognize the observed object. It is considered to be the date for the start of work on such coloring in 1909, when the American artist Abbott Handerson Thayer published the book "Concealing Coloring in Animal Kingdom", which described the methods of disguise used in nature. And in 1939, the French artist of Russian origin Vladimir Baranov-Rossine patented a spotted military uniform ("pointillistic dynamic camouflage") or "chameleon method" ^[5]. Regardless of the primacy of the invention, the very concept of "camouflage" appeared in Russian and many other languages from French camouflage. The principles of masking proposed by these authors did not just bring the color of the object closer to the background of the terrain, they provided blurring of the contours of objects, making it difficult to determine their type by visually distorting the size, hiding the nature of actions and direction of movement, implementing a fundamentally new approach to increasing stealth.

However, it is possible to talk about any scientific priority in terms of the invention of camouflage quite conditionally: practical work on the creation of camouflage uniforms was carried out simultaneously with France in Germany, where the "splinter" WH splintentarn of 1931 (German Splittertarnmuster, literally: needle camouflage pattern) or "colorful" camouflage (German Buntfarbenmuster, literally: color camouflage pattern), M1929 Telo mimetico (it. Telo mimetico, camouflage fabric) was created in Italy, research was conducted in other countries.

3.2. The development of camouflage during the Second World War

By the beginning of World War II, camouflage was used in all the leading armies of the world, but not massively, but in the form of capes and camouflage suits used by military specialists solving important tasks requiring secrecy: scouts, snipers, sappers.

With the development of the chemical and textile industries, the possibility of mass production of inexpensive, resistant and diverse artificial dyes has appeared. Accordingly, the cost of complex fabric coloring has decreased and mass production of uniforms directly from camouflage material has become possible.

On the one hand, this has generated a number of positive factors:

- the list of supply items has decreased;

- the camouflaged field uniform is more convenient to use than the additional camouflage suits worn over the uniform;

- the use of camouflage has been made widespread.

Recall that almost any modern field uniform serves to implement two functions: deforming, distorting the contours of the object, and imitation, bringing the color of the masked object closer to the background:

- the imitation function is provided by using in the camouflage pattern the colors most often found on the terrain where it is planned to conduct combat operations with the choice of the most characteristic of them as the main one;

- the implementation of the deforming function is provided by the selection of the shape, size, relative position and color of the elements of the camouflage pattern.

At the same time, during the development of camouflage, it is necessary to take into account that large components more successfully provide a solution to the first function, and small ones – to the second. Taking into account this postulate, during the development of the camouflage pattern scheme, it is constantly necessary to solve the variational problem of color selection and optimization of the size and shape of the components of the camouflage pattern.

In the interests of providing both deforming and imitation functions, army camouflage patterns were developed for the specific type of terrain on which it was intended to conduct combat operations. The camouflage was created taking into account both the geographical features of the area of the intended battle and the time of year. For example, winter camouflage has been used quite actively since the Second World War and up to the present time – white masks and suits worn over the main uniform. These suits come in both plain white and two- or three-color spotted coloration, such as the German Schneetarn ^[6].

In the Red Army, camouflage uniforms were adopted for supply before the outbreak of the Great Patriotic War for snipers, sappers and scouts. At first, they were hooded camouflage robes worn over the main uniform. Where, in fact, did the word "camouflage" used in the Russian language to define almost any camouflage suit come from. Later, camouflage robes were replaced with more practical suits consisting of a jacket and trousers, also worn over the main uniform and made of the same light cotton fabric as the masks, with a summer pattern of uneven spots in the shape of an amoeba, brown or black, applied on a basic khaki or green background. The official name of such a scheme is "deforming coloring of the 1935 sample". In 1942, camouflage suits of light green color with leaf-shaped patterns appeared (the "deciduous forest" coloring), and in 1944 – the "palm" type coloring of four types ^[3]. White fabric was used for winter camouflage kits.

During the same period, the use of camouflage uniforms was actively carried out by the allies of the USSR in the anti-Hitler coalition. For example, the US Army used camouflage in the European Theater of Operations, which served as a prototype for a later version of Woodland: a pattern with irregularly shaped spots of four colors. In the Pacific Theater of Operations, US Marine Corps soldiers used the US pacific camouflage, which was a basic khaki base, on which patches of green, light and dark brown colors were applied. Camouflage suits were made double-sided, with different color options on different sides of the fabric, which allowed them to be used in operations in areas with different soil and vegetation ^[3]. Which, however, turned out to be not very convenient from the point of view of the practical use of suits, the convenience of wearing them.

During the war, the British Army used "Denison smock jackets" with a "smear" type of coloring. The pattern of the jacket's fabric included a combination of spots and smears of sand, green, brown and black colors, which became the prototype of modern DPM (Disruptive Pattern Material) camouflage.

However, the practice of warfare has shown that the use of camouflage uniforms still has certain limitations. For example, if the Theater of operations itself is not changed often, then there is a change of seasons, which is an objective factor affecting the requirements for camouflage. It is not always economically feasible to change uniforms for each season, so it is still easier to use camouflage capes and robes. Which are also cheaper to produce, which is important for mass armies. In addition, ordinary uniforms do not have some of the factors of specialized suits, they distort the physical contours of objects less. Therefore, during the Second World War, and now for winter conditions or for personnel solving special tasks in which secrecy is more important than convenience, specialized camouflage kits or capes are used.

In addition to the regular ones, improvised means were often used for disguise. In summer, camouflage robes were supplemented with cut branches, in winter, instead of camouflage capes, ordinary white sheets were sometimes used manually modified. Simple medical bandages could be used for camouflage wrapping of weapons in winter.

During the same period, camouflage uniforms were actively developing in the Axis countries. In the German army, back in 1931, the Zeltbahn-31 camouflage cape appeared, implementing a "splintered" pattern (German Splittertarnmuster). During the Second World War, after experiments with sharp-angled "splintered", "schrich" (H eerres-Splittermuster-31) and "deciduous" colors (Buntfarbenmuster, swamp camouflage Sumpftarnmuster) used in the Wehrmacht, a fairly effective camouflage coloring was developed for the Waffen-SS troops "Flecktarn" (Flecktarn, from the German der Fleckt – "spot, blot" and die Tarnung – "disguise"). "Flectarn" is a three-, four-, five- or six-color "explosive" camouflage coloring. The use of groups of multicolored dots created a "noise" optical effect, eliminating clear boundaries between different colors and blurring the contours of the masked object.

By the end of 1944, the Wehrmacht used up to forty variants of camouflage colors in different variations, implementing mainly Flecktarn variants: Eichenlaubmuster, Platanenmuster, Rauchtarnmuster, Palmenmuster, Sumpftarnmuster, Erbsenmuster, Leibermuster and the like (Figure 1). The "oak leaf" variant (Eichenlaubmuster) had as variations a six-color SS-Beringt-Eichenlaubmuster and a five-color SS-Eichenlaubmuster version. The army camouflage also had variations: Splittermuster A (splintered, mod. 1931), Splittermuster B (splintered, mod. 1941), Splittermuster C (splintered, mod. 1943), Splittermuster D (splintered, mod. 1944), Sumpfmuster A (swamp, mod. 1943) and Sumpfmuster B (swamp, mod. 1944).

At the same time, the main means of camouflage in the German army of that period was the Zeltbahn-31 cape, made in "dashed" colors. In addition, Tarnhemd jackets and Tarnhelmuberzug helmet covers in the same "dashed" colors or winter version were actively used. Various variants of the "flectarn" coloring were used to create special camouflage uniforms: suits consisting of camouflage jackets or blouses, and trousers.

Camouflage jackets and blouses were originally designed to be worn over the main uniform, so slots were made on the sides to access the pockets of the main uniform and equipment. The silhouette of jackets and trousers was made baggy, for additional distortion of the contours of the figure. The sleeves in the lower part were tightened with elastic bands or laces, the collar was also provided with lacing, the hood, which replaced the collar, was tightened with a lace. On later versions of the jackets, external pockets and flaps were added to cover the slots. Since 1944, belt loops have been sewn on the shoulders and sleeves to attach branches or tufts of grass to them.

Many of these solutions later became classics for camouflage uniforms.

But, despite the fairly successful experience of using uniforms in the colors "flectarn", the fact that it was used mainly in the field units of the Waffen-SS, formed a certain negative attitude towards a fairly promising method of coloring – after the war, the "flectarn" was forgotten for a long time, returning to use only in the late 1970s ^[3].

Fig. 1. Variants of camouflage coloring of Wehrmacht uniforms: Splittertarnmuster on the left, different versions of Flecktarn on the right (collage by the author)

The allies of the Germans also had their own developments in terms of camouflage, implemented mainly in the form of army capes, such as, for example, the Italian tent tent (it. telo tenda) in the M1929 Telo mimetico coloring.

3.3. The development of camouflage in the post-war years

The experience of the Second World War showed the high importance of disguising personnel to ensure their protection on the battlefield. It is logical that in the post-war years, the development of camouflage methods and the improvement of camouflage colors for field uniforms continued.

In terms of leading foreign countries, taking into account the informatization of the battlefield, since 1984, most camouflage patterns for the Armed Forces of the United States and other NATO countries have been implemented in a "digital" version. The most common "digital" pattern of the US Army is considered to be the basic camouflage Universal Camouflage Pattern (UCP), implemented in the ACUPAT (Army Combat Uniform Pattern) kit and including color options for various conditions: basic (general), desert (desert), forest (woodland), mountain (highland) and urban, made in shades of gray (urban). According to official designations, the UCP versions are divided into: Army UCP (Current), UCP A, UCP B, UCP C, Modified UCP D and Modified UCP E. There are varieties of camouflage pattern by belonging to the branch of the armed forces, for example, the US Marine Corps used its own version of ACUPAT – MARPAT (Marine Pattern) in Woodland, Desert and Winter variants.

Since 2010, the seven-color camouflage pattern MultiCam (MultiCam, MC), which is considered universal for various terrain and urban conditions, has been adopted for the supply of special operations forces of the US Army. In addition to the basic version, variants of this coloring have been created for units operating in Afghanistan (MC Arid), in tropical areas (Multicam Tropic), an option for police units (MC Black), as well as MC Alpine. The MultiCam version is adopted by the UK Armed Forces under the name Multi-Terrain Pattern (MTP), replacing the DPM camouflage. However, for the US Army, the UCP camouflage coloring remains the main one.

The armies of other NATO countries use color options DPM (Disruptive Pattern Material), MTP, CCE camo (Camouflage Central European), Flecktarn, Tropentarn, Multitarn, M/03 (N-Ørkenkamo), Vegetata, wz.93, Turkish pattern and others (Figures 2 and 3). Many variants of modern camouflage, implemented in the armies of small states, are direct copies or variations of well-known drawings from leading developers in this field. So, the Danish camouflage Flectarn-D, the Norwegian M75 and M98 and the Japanese Jeitai are versions of the German "flectarn", and the Swedish camouflage coloring M/90 is a modern version of the German "splinter" camouflage splintentarn. The Canadian Army uses the CADPAT camouflage coloring, which is a version of MARPAT, and the French CCE Camo camouflage coloring has significant similarities with the old American Woodland.

However, there are also original designs, such as the Finnish camouflage M05, the digital scheme of which was created taking into account the colors of Finnish forests. The National Liberation Army of China (PLA) uses its own versions of the Type 87, Type 97, Type 99 camouflage, created on the basis of the "flectarn" pattern, as well as the Type 07 pixel camouflage.

Most camouflage colors, as already noted, have variations for different theaters of war and/or seasons: vegetation, desert, urban colors, winter and others. Thus, the English DPM camouflage has a desert version of DDPM, the Italian armed forces use the Vegetato camouflage coloring (a "digital" pattern of brown, sandy and black spots on a green background) and its desert version Desertato. The French CCE camouflage has a desert version based on the Daguet Desert pattern, and the German Flectarn is also available in the desert version of the Tropent a rn (3-Farb-Tarndruck). For actions on specific TVD, specialized colors are used, such as the French "Leopard" (Lizzard pattern) and the Cuban "Tiger" (Tiger), used in the jungle, or the American Snow camo, used for actions in the Arctic regions. The variety of options ensures that the basic set of colors is as close as possible to the coloring of the terrain on which it is supposed to conduct combat operations. After all, as studies have shown, poorly chosen camouflage colors lose out in providing concealment to the uniform color of the field uniform, close to the background of the terrain. And again, let's remember that camouflage should implement not only a deforming, but also an imitation function. Taking into account the complexity of the simultaneous implementation of these functions in all application ranges, to date, simple uniform colors such as khaki, olive Green or dark olive Drab, green-gray (Feldgrau) are sometimes used in field uniforms.

Fig. 2. Variants of camouflage of NATO countries, from left to right: Woodland, UCP, MARPAT, Fecktarn (collage by the author)

Fig. 3. Variants of the desert camouflage of NATO countries, from left to right: DPM Desert of the British army, six-color desert of the USA, UCP, Tropentarn (collage by the author)

The further development of modern foreign camouflage is determined not only by the improvement of the shape of the pattern and its colors, there are prerequisites for fundamental changes. So, in open sources there is information about the development by the American company Kryptek of the so-called 3D camouflage, which should implement more effective optical deception techniques.

Research and development work (R&D) in the interests of improving camouflage colors was carried out in the army of the USSR, and then in Russia. In the Soviet Union, the "silver leaf" pattern of the 1957 sample was developed for camouflage overalls (the official name is "Coloring of the 1957 model, the "Silver Leaf" variant, aka "Birch", KLMK suit), the basic camouflage for the field uniform "Butan/Dubok" of 1984, which existed in the form of color solutions for forests and for desert-steppe areas. A special KZS suit had a coloring similar to the "birch tree", only in a different color scheme. This mesh suit, in addition to optical camouflage, provided protection from intense light radiation due to a special impregnation that forms a haze when heated ^[7].

The armies of the Warsaw Pact countries used their own camouflage variants, most of which were formed according to the principle of the German "needle" coloring (German Strichtarn) with different variations, such as additional spots or transverse strokes. The exception was the uniform of the Hungarian army in the colors of the "tereptark" M49/82. The GDR Army (Nationale Volksarmee, NVA) used variants of the NVA Flachentarn (Flächentarnmuster, Blumentarn) and NVA Strichtarn.

The first variants of camouflage of the Russian army: The HRV-93 and HRV-98 Flora were created using Soviet developments. Subsequently, a completely new camouflage pattern was developed – "Digital Flora", which reduces the level of visibility of military personnel, especially for electronic-optical surveillance equipment (the official name is "Uniform Camouflage Coloring (EMR) + color code / variant"). In addition to the Ministry of Defense, camouflage patterns have been developed for other law enforcement agencies that have their own uniform supply agencies. Taking into account their specifics, camouflage is created mainly in urban colors, realizing shades of gray and dirty blue colors. Variants of such drawings for the city can be considered "Gray reed", "Gray city" or "Gray figure". For actions outside urban conditions, units of other law enforcement agencies use foreign schemes adapted to Russian conditions: "Tiger", "Surpat" or "Spectrum".

It should be noted that by mentioning the "official" names of camouflage, the authors somewhat sin against the truth, simplifying the situation – the names of the types of colors are used in special documents and during R&D, or in commercial names of camouflage, and the field uniform itself, including in camouflage colors, differs only in the articles of the nomenclature of the clothing service ^[6].

When masking, certain attention is paid not only to the elements of equipment and weapons, but also to the masking of open areas of the body: the face and hands. Even in early versions of camouflage suits, fabric masks made of the same material as the suit itself, as well as protective nets, were used to cover the face. Later, the face and hands began to be masked with special makeup of different colors. Gloves are often used to mask the hands, which, in addition to the protective color, can also protect the hands from cold and mechanical damage.

The use of interchangeable elements for disguising equipment and weapons, which are changed by the servicemen themselves, allows you to bring the camouflage color as close as possible to the terrain where the servicemen are currently operating, as well as dynamically adapt the disguise to the changing seasons. This is especially true due to the fact that the vast majority of equipment and weapons, unlike uniforms, are not seasonal.

Moreover, replaceable components can be endowed with additional useful properties, for example, water resistance and volume (Figure 4). The interchangeable component approach has additional useful applications. For example, army bowlers in the Soviet army were painted with protective enamel, and aluminum landing kits were not painted, they were carried in a protective cloth cover. After cooking on a campfire, the paint of the army pot burned, and the pot from the landing kit was removed from the cover during cooking, and after cooking it was easily wiped off with sand.

Fig. 4. Camouflage waterproof backpack cover with 3D effect (photo from the website https://mordor-tac.com )

The most effective is considered to be the complex application of camouflage measures. For example, when physical distortion of the contours of a figure is used together with protective coloring. Based on this, in addition to camouflage coloring of uniforms and covers, other methods of camouflage are used: distortion of the contour of the figure due to capes, baggy cut of uniforms and special patchwork suits, applying special paints to exposed areas of the body, the use of local objects and materials – branches and dirt, etc. The use of such methods is often realized due to improving the components of the field uniform, for example, inserting a wire into the edge of the hood that can bend and set a shape that distorts its silhouette, or a patch on the uniform of special loops that serve to attach torn branches to it.

In modern conditions, when technical means of reconnaissance and surveillance began to play a significant role on the battlefield, it was necessary to expand the protected range. And even though the ultraviolet part (Ultraviolet, UV) of the spectrum is practically not used by reconnaissance means due to its increased absorption by the atmosphere and sensitivity to air transparency, but in addition to the visible (visible L ight S spectrum, VS, Vis), its infrared part (Infrared, IR) is actively used. Accordingly, suits and multi-layered fabrics are added to the camouflage in the visible spectrum, providing reduced visibility in the infrared, and sometimes in the radar range. An example is a variant of the MARPAT delta camouflage uniform, which provides reduced visibility in the IR range.

As with the use of optical camouflage, there are examples of the use of improvised means in other ranges. During the war in Iraq, the soldiers of the Iraqi army, who did not have specialized means of protection from IR surveillance devices, used ordinary blankets, which for a while allowed them to weaken the radiation in the infrared spectrum. For similar purposes, a shelter among vegetation was used, which shields radiation in various parts of the spectrum with varying degrees of success. Of course, these are partial measures that reduce radiation only for a while and without guaranteed results, but they worked.

Considering the use of camouflage coloring on the battlefield, it is impossible not to recall the camouflage of combat and other equipment: land, sea and air-based. In various historical periods, camouflaged coloring books were used to increase stealth and technology, of course, taking into account the environment of its functioning. However, taking into account the size, noise and composition of the equipment, various camouflage nets and screens, natural and artificial shelters, as well as aerosol curtains, traps and reflectors of various ranges are more often used to mask it ^[8].

It should be remembered that at the stage of the appearance of protective coloring, animals on the battlefield were draped in the color of "khaki". If wild animals, for the most part, match their coloring to the surrounding area, then domesticated ones, most often, do not have this quality. This also applies to animals used in various capacities on the battlefield. Currently, there are a lot fewer of them, animals are used mainly to solve specific tasks: sapper dogs, pack transport in difficult terrain conditions. But for those animals that are currently used for military purposes, protective coloring has not lost its relevance. An example is a camouflage cape for pack animals carrying 81 mm mortars in the Indian Army (Figure 5).

Fig. 5. Camouflage for animals (photo from the website newsofrussia.ru )

3.4. About the technologies of camouflage pattern development

As part of the analysis of the development of camouflage as an element of ensuring military operations, it is interesting to study the technological process, namely, the appearance and development of various types of camouflage uniforms. Like any military equipment, camouflage evolved with the development of technology, the improvement of forms and methods of warfare. Its development was a complex scientific task, solving several problems in a complex, one of which is the contradiction between the need to meet the parameters and tasks solved at each specific point on the battlefield, the availability of technological and economic opportunities to achieve this goal. To provide a solution to this problem, camouflage patterns were divided into enlarged groups during development, similar in terms of conditions of use, mainly by type of terrain and season.

An equally important problem was the development of new types of drawings and their effectiveness testing.

For a long time, the subjective component prevailed in this process: developers, guided by their own logic and intuition, and hints received from nature, created their own camouflage options. These options were tested for imitation and deforming qualities in different areas of the terrain, the results were averaged, after which a conclusion was made about the acceptance of the drawing for supply or the need for its completion.

Initially, the camouflage assessment was carried out with the involvement of experts to conduct field experiments on the ground. Subsequently, with the advent of color photography, it was possible to reduce the cost of experiments by applying photo modeling methods and moving the activities of experts from landfills to laboratories.

In both cases, the characteristics of human vision in the daytime were taken as indicators and criteria determining the effectiveness of the detail and color saturation of the drawing, its geometric construction and contrast. That is, the assessment remained subjective, and the method of searching for new drawings was iterative and weakly directed.

With the development of computerization, it became possible to use mathematical modeling technologies and other precise methods for both developing camouflage patterns and evaluating them. For the assessment, the indicators of the mean Square error of object recognition (Mean Square Error — MSE) and the calculation of the Peak Signal Noise Ratio (PSNR) were used. But the most effective tool for evaluating the effectiveness of the camouflage effect is considered to be the use of the Universal Image Quality Index (UIQI), which correlates well with the psychophysical indicators of the human Vision System (HVS) ^[9]. Based on taking into account the standard deviations of the levels of various parts of the spectrum in the studied image, the UIQI index takes into account the correlation coefficient of images, brightness and contrast of information, which allows us to form comprehensive estimates of the effectiveness of camouflage patterns. Using the values of the UIQI coefficient, the probability of detecting a masked object in various conditions of its observation can be obtained.

The next logical step in the development of the camouflage development process is the transition from UIQI evaluative mathematical models to prescriptive ones, which allow purposefully developing a camouflage pattern optimized for specified sets of background conditions. That is, models that provide an automated search for new variants of drawings and colors according to specified criteria.

3.5. About some other camouflage applications

Practice shows that camouflage can be used not only for its intended purpose, in combat, but also for other purposes, sometimes far from the field of armed confrontation.

One of the notable aspects is the use of camouflage fabrics in fashion. Historically, after any war, there are unspent stocks of weapons, equipment and uniforms. Storing them with the prospect of future use is usually costly and pointless: the peacetime army does not need them too much, and a new war will most likely require new equipment. Therefore, stocks are usually sold at minimal prices, which is used by merchants and ordinary citizens. A good example of the implementation of this approach is the history of the Leroy Merlin retail chain, which began with the stores "Stock American" (Au Stock Americain) ^[8].

This principle also applies to military uniforms left over from the fighting. For example, a practical and durable army uniform that went on sale was liked by many after the end of World War II ^[10]. And in the 60s of the last century, after the end of a series of national liberation and anti-colonial wars, the widespread use of military uniforms gave rise to the military style. A notable element of this style is camouflage clothing. In the 70s of the last century, the "military" style became a symbol of various youth subcultures, protests against wars and violence. Young men in military uniforms on city streets hoped to make the townspeople feel what it's like when there are battles and soldiers walking on your streets. The second wave of fashion for the "military" style occurred in the late 80s - early 90s of the last century.

And to this day, elements of the "military" style remain in fashion: rough boots, elements of army equipment used as brutal accessories and, of course, camouflage jackets, trousers and hats.

Of course, the functionality of civilian camouflage differs significantly from the military, neither imitation nor deforming functions, nor mass production are optional for it. Therefore, it may contain not only differences in the quality of the fabrics used, but also differences in the requirements for the camouflage pattern used, which serves not the purpose of increasing secrecy, but giving a certain brutality, symbolism.

Separately, camouflage for "women's military" can be distinguished, which is often dominated by pink, blue and other delicate colors. Of course, the imitation function in such camouflage is not the main one. Moreover, its use often solves the exact opposite task – not to hide, but to stand out. In addition, for both women's and sports camouflage, there is usually no requirement to perform not only an imitation, but also a deforming function: often such things are performed according to the figure. Moreover, it is quite possible to solve the reverse problem for the camouflage pattern, which has not yet been directly posed – for female camouflage, it is possible to assume the development of deforming schemes that conceal the size of the figure, visually ensuring "weight loss". Or even a more non–trivial task, which has not yet been formulated - visual size adjustment in the necessary places, both downwards and upwards.

Nowadays, as at the end of the twentieth century, camouflage as durable and non-marking clothing is becoming a symbol of street protests. A baggy silhouette and a cap with a visor play a certain role in this, making it difficult to visually identify the protesters by means of video recording. With this in mind, in some countries, wearing camouflage clothing at mass events is strongly discouraged ^[6].

Another notable trend in the use of camouflage in the civilian sphere is the use of camouflage suits and capes by hunters. On the one hand, hunters and tourists actively use regular field uniforms, inexpensive and practical. On the other hand, there is a fairly large selection of specialized suits for hunters, tourists and fishermen, designed specifically taking into account the conditions of use. Taking into account the smaller volume of production and the higher allowable price, specialized camouflage suits are characterized by high quality fabric, it can have "breathable" and water-repellent properties. From the point of view of drawing, unlike army standardized approaches, camouflage colors created by various companies and organizations engaged in the development and production of specialized clothing for hunters are usually non-standard. Examples of non-standard camouflage colors are the Russian variants "reed", "autumn forest", "sedge", or the Canadian Duck hunter.

In general, there are certain differences from military camouflage in this area of camouflage. In terms of imitation properties, they are determined by the peculiarity of animals that most of them have dichromatic vision, which does not allow them to distinguish many colors. Therefore, specialized hunting camouflage sometimes simultaneously solves two tasks: it provides a crucifixion of the hunter's silhouette to make it less noticeable to animals, and marks the hunter to show his position to his companions. Based on this, it often uses colors of bright shades: red, signal pink. Birds, unlike animals, have tetrachromatic vision, so the option with bright camouflage is not suitable for hunting them. At the same time, in this case, the colors may differ from the classic ones, given that the range of visual perception of birds may be wider than human.

Another factor that significantly affects the pattern of hunting camouflage is the significant differences in visual acuity of humans, animals and birds. With this in mind, in terms of deforming requirements, when developing hunting camouflage, it is taken into account not only that symmetrical and repetitive elements are rarely found in inanimate nature, therefore, the camouflage pattern should be as chaotic as possible so as not to alarm the hunting object, but also the detail of its components should correspond to the visual acuity of animals and birds. Along with other features, this distinguishes specialized hunting camouflage from army camouflage.

However, these aspects are not predominant, the main purpose of camouflage was and remains to be used in the military field.

3.6. Some historical and practical conclusions

An analysis of the history of the creation and use of camouflage uniforms allows us to identify the main stages of this process:

1) providing optical stealth by visual methods:

- implementation of the simulation function by approximating the color of the object to the colors of the main background;

- implementation of the deforming function through the use of camouflage colors;

2) additional provision of secrecy due to the physical distortion of the contours of the figure, the use of local objects;

3) the spread of protective paints on the elements of weapons and equipment;

4) ensuring stealth in other ranges in which the enemy's means of reconnaissance and aiming operate;

5) development of methods to ensure secrecy in new areas covered by armed struggle.

In addition to these stages, other approaches are used in the process of improving the camouflage properties of military uniforms. For example, not being able to reliably hide an object in conditions of high density of intelligence assets, you can take advantage of the fact that their resource is not infinite for the enemy, and distract his attention using false objects or mimicry of protected objects for less important ones, get lost among similar ones.

The most obvious example of such mimicry is implemented in all modern armies. This is when, in peacetime, the military uniform has significant and noticeable differences from a distance for privates, sergeants and officers, and the field uniform for the categories of ordinary and commanding personnel is practically indistinguishable even at a short distance.

The analysis of the state of the subject area allows us to conclude that, despite the change in the conditions of warfare, the "ordinary" army camouflage has not lost its importance in modern conditions. And, probably, it will not lose in the future.

Moreover, at present, the use of camouflage has become so effective that it required solving the inverse problem – to restore the recognition functions, at least partially. Recently, it is often possible to notice in video reports from areas of local wars and armed conflicts how the opposing sides add colored components to the uniform – armbands or headbands of a predetermined color. This is done precisely in order to distinguish between one's own and others dressed in similar camouflage in the conditions of dynamic combat operations. As part of solving this problem, in military history, many other methods of identifying their military personnel can be noted: from the sound of "clickers" used during the Allied landings in Normandy to red lanterns on helmets facing the rear, which were used in the US army during the Vietnam War. Currently, more technologically advanced methods of identifying personnel on the battlefield are being used, such as NATO's "friend-foe" millimeter-range Cooperative Target ID System and personal optoelectronic DSID (Dismounted Soldier Identification Device) ^[2,11,12]. However, in the current situation, a non–trivial scientific task may well be formulated - to develop a camouflage that hides a soldier from the enemy and shows his place to his own. For modern types of "digital" colors, such a solution, for example, may be the use of QR-code technologies, with the help of which, in a pixel drawing of camouflage uniforms, messages about the ownership of the owner of the camouflage suit can be encrypted. Given the constant increase in the number of robotic tools, such identification is becoming especially relevant for vision systems.

4. Conclusion

Summarizing the material of the article, it can be concluded that masking in the optical spectrum, in all its ranges, remains quite relevant in modern conditions.

Firstly, despite the appearance on the battlefield of surveillance and aiming devices operating not only in the visible, but also in the infrared and radio bands, optical camouflage is still very important to reduce losses of personnel and equipment ^[13,14,15]. The principles developed for optical masking and tested in practice can be used to solve similar problems in other ranges and environments. And the use of historical experience, proven methods of reducing optical visibility, remains relevant.

Secondly, it would be logical to expect the spread of the principles of using camouflage colors to implement such properties not only in different ranges, but also from all angles, including camouflaged canopies and capes covering personnel from the upper hemisphere when on site. Including on the basis of camouflage, developed taking into account the peculiarities of the technical vision of unmanned vehicles, which are becoming more and more on and above the battlefield ^[6,16,17]. Taking into account the requirements for the complexity of the tasks to be solved, masking canopies, for example, in addition to camouflage properties, can, when given a certain rigidity, additionally serve as "umbrellas" for anti-theft protection, etc.

Thirdly, the potential for the development of camouflage means has not yet been exhausted: on the one hand, the development of autonomous robotics and the active appearance of robotic systems on the battlefield requires increased stealth from technical vision, on the other – and the process of borrowing from nature, from which, in fact, the development of camouflage began, has not yet been fully realized. There are, for example, living beings that dynamically change color according to the situation, and this natural property was tried to be repeated by experts from Seoul National University, who developed artificial skin that changes color when the temperature of nanowire heating elements controlled by a computer changes. The created coating can not only change color, but also form patterns. This is still a prototype, but with prospects for using optical masking in practice.

Another option for dynamic color management, which can be borrowed from nature, is to change the visible color due to the surface structure, which changes the parameters of light reflection, like the white scarab (Cyphochilus insulanus). An even more perfect mechanism for using this effect is shown by the variable coloration of the rainbow hummingbird (Coeligena iris), the color of which can change not due to a set of basic colors, but due to changes in the angles of reflection of the feathers when they turn.

In the case of creating camouflage based on such methods, such dynamic camouflage will provide a significant increase in the imitation characteristics of the camouflage form by taking into account even small changes in the properties of the terrain, seasonality and time of day. However, these approaches provide an imitation function of uniforms, in order to implement the deforming function, it is necessary to have prescriptive methods of forming a camouflage pattern, the need for the development of which was mentioned earlier.

Moreover, it seems quite possible that similar approaches can be used in other ranges, for example, in the infrared, by bringing the IR radiation of an object to the background level by equipping it with temperature sensors and distributed means of individual air conditioning. Moreover, analogues of this approach can be found in history – during the war, snipers, being in ambush, deliberately chewed snow to cool their breath and not give themselves away with steam from their mouths. However, given that there is no absolute protection against observation in the IR or radar range, it can be assumed that the approach implemented in optical camouflage is used as an addition to the currently used simulation approaches implemented by reducing the radiation level: the transition to deforming ones is the purposeful fragmentation of the thermal or radiocontrast silhouette of the protected object in these ranges, making it difficult its contour recognition.

Another natural property that has not yet been realized is the setting of personal concealing veils, as, for example, squids or octopuses do. It is quite possible, within the framework of borrowing, to provide military personnel with the means of setting personal aerosol curtains of directional action or with specified properties.

That is, despite the growth of technological capabilities, much of what is available in nature has not yet been realized in disguise. Work in this area is likely to continue in the future ^[18,19,20].

Fourth, analyzing the still unrealized potential opportunities for increasing stealth, it is worth considering that the main purpose of disguise is to make sure that the enemy does not see what actually exists, could not correctly assess the objects and the situation. Taking this into account, it can be concluded that ensuring secrecy can be realized not only by changing the properties of the object, but also by directional distortion of the perception of the latter by the observer. The point is that the development of technologies, the use in management practice of technical means of collecting and processing information, augmented reality (AR) and virtual reality (VR) technologies, generates new opportunities in distorting information about objects given to the observer. The approach of influencing the observer's brain through the colors and configuration of the drawing was developed by the Soviet avant-garde artist Ya.G.Chernikhov in the 40s of the last century. The same approach can be implemented to mislead software algorithms for processing visual information. As part of solving such problems, there are known options for the practical implementation of the formation of a "digital" pattern of clothing, obtained on the basis of an analysis of vulnerabilities of neural network image recognition algorithms, due to the use of which an object normally distinguishable by a person is not recognized by hardware and software surveillance complexes. In the future, such and even broader opportunities can be realized by distorting or adding virtual information about real objects that change their perception, which may even give rise to fundamentally new directions in disguise.

And the last thing: As historical analysis shows, methods of increasing stealth are effective not only when they are rationally prepared, but also when they are used in combination and purposefully, combined with other measures to mislead the enemy, implemented both directly on the battlefield, at the tactical level, and in higher instances. Including, as already noted, in a wide variety of ranges and spheres. This fact must be taken into account both when developing them and when organizing the practical application of camouflage.

Thus, the analysis of the historical experience of the development of scientific and technical approaches to ensuring the safety of personnel by increasing secrecy allows us to formulate a number of scientific and practical tasks for the development of camouflage pattern:

- the use of new technologies in camouflage uniforms that provide dynamic changes in colors and patterns;

- extension of the principles of ensuring secrecy, both imitation and deformation, to other ranges of observation, except optical;

- development and implementation of methods for purposefully misleading enemy surveillance equipment, implemented not only by improving the imitation and deforming properties of uniforms with respect to the features of technical vision systems, but also by developing specialized algorithms triggered, for example, by requests (prompt) encrypted in a camouflage pattern;

- the return of the "friend-foe" identification functions to uniforms, both by creating characteristic colors and patterns, and by other methods, for example, using QR codes "sewn" into the pixel pattern of the "digital" camouflage for reading by technical means of observation;

- improvement of camouflage pattern development methods, abandoning iterative approaches to development in favor of prescriptive ones that form variants based on the analysis of the initial background and specified requirements, including in dynamic mode;

- giving additional properties to camouflage uniforms, such as physical protection of a serviceman from shock, protection from adverse natural factors and others.

Perhaps the solution of these tasks will determine the prospects for the development of camouflage uniforms in the near future and even change approaches to ensuring combat operations – practice and historical analysis of current and future conflicts will show.