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The threats’ fast adaptation, hybridization, the proliferation of innovative technologies, and increasing lethality of threats, highlight the importance of enhancing the Land Systems (both soldiers and platforms) protection. Camouflage has broad applications in nature, engineering, and the military.
Camouflage comprises the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see (crypsis), or by disguising them as something else (mimesis). Examples include the leopard’s spotted coat, the battledress of a modern soldier, and the leaf-mimic katydid’s wings. From squid who turn themselves the color of ocean sand to brightly colored chameleons, natural camouflage is a powerful evolutionary skill to avoid predators.
A third approach, motion dazzle, confuses the observer with a conspicuous pattern, making the object visible but momentarily harder to locate. Some camouflage systems (eg. SAAB’s Barracuda) rely on this mechanism, disturbing the shape of the protected object so that even if it is detected, it can’t be easily recognised or identified.
Military camouflage has been the subject of continuous improvement and research for over 100 years – ever since the realisation that, supplying troops and equipment with colours matching the ambient environment could lead to improved protection and survivability.
Camouflage has been used to protect military equipment such as vehicles, guns, ships, aircraft and buildings as well as individual soldiers and their positions. Vehicle camouflage methods begin with paint, which offers at best only limited effectiveness. Other methods for stationary land vehicles include covering with improvised materials such as blankets and vegetation, and erecting nets, screens and soft covers which may suitably reflect, scatter or absorb near infrared and radar waves.
Many camouflaged textile patterns have been developed to suit the need to match combat clothing to different kinds of terrain (such as woodland, snow, and desert). The design of a pattern effective in all terrains has proved elusive. Lower mass better protected military platforms and soldiers are easier to operate at reduced risk for injuries.
Some military textiles and vehicle camouflage paints also reflect infrared to help provide concealment from night vision devices. After the Second World War, radar made camouflage generally less effective, though coastal boats are sometimes painted like land vehicles. Aircraft camouflage too came to be seen as less important because of radar, and aircraft of different air forces, such as the Royal Air Force’s Lightning, were often uncamouflaged.
A good camouflage coverage changes the appearance or signature respectively and prevents from being detected, recognized or identified, and furthermore from being, attacked, hurt, killed, damaged or destroyed. Various camouflage measures have been used in many conflicts and have led to partially astonishing and impressive results. Legacy camouflage techniques and means are normally passive materials with fixed technical properties and with no possibility to adapt or change them. Hence, the signature remains unchanged if the background changes due to movement for example. These conventional techniques are being used in nearly all military situations, missions, scenarios and environmental conditions.
Active Camouflage
Researchers are developing Active camouflage or adaptive camouflage technology that is camouflage that adapts, often rapidly, to the surroundings of an object such as an animal or military vehicle. In theory, active camouflage could provide perfect concealment from visual detection. Scientific sources estimate that in five years this colour-changing technology could also be used to disguise military vehicles on the battlefield.
Active camouflage is used in several groups of animals, including reptiles on land, and cephalopod molluscs and flatfish in the sea. Animals achieve active camouflage both by color change and (among marine animals such as squid) by counter-illumination, with the use of bioluminescence.
Military counter-illumination camouflage was first investigated during World War II for marine use. More recent research has aimed to achieve crypsis by using cameras to sense the visible background, and by controlling Peltier panels or coatings that can vary their appearance.
Active camouflage may now develop using organic light-emitting diodes (OLEDs) and other technologies which allow for images to be projected onto irregularly shaped surfaces. Using visual data from a camera, an object could perhaps be camouflaged well enough to avoid detection by the human eye and optical sensors when stationary. Camouflage is weakened by motion, but active camouflage could still make moving targets more difficult to see. However, active camouflage works best in one direction at a time, requiring knowledge of the relative positions of the observer and the concealed object
Italian computer scientists Franco Zambonelli and Marco Mamei have outlined the requirements for a fabric coated with miniaturised LEDs and cameras that, by projecting the appropriate background image in all directions, could confer genuine invisibility. They say that current technologies are almost up to the task and estimate that it could cost under 500,000 euros to build a prototype.
HyperStealth patents military “Invisibility Cloak”
In 2019, HyperStealth Biotechnology Corporation, a manufacturer of camouflage uniforms used by the military, has announced that it has recently filed a patent application relating to a “Quantum Stealth Light Bending Material” which it refers to, in a nod towards Harry Potter’s famous item of clothing, as an “Invisibility Cloak”.
According to CEO and president Guy Cramer, who founded the Canadian company in 1999, “True invisibility was thought to be impossible by most physicists. Not only does the material hide a target in the visible spectrum but … it also bends in the Ultraviolet, Infrared and Shortwave Infrared while it blocks the Thermal Spectrum, making it a true ‘Broadband Invisibility Cloak’”.
In a pitch designed to highlight the potential military applications of the new technology, HyperStealth claims that by “bending” light around any given object, the material could effectively “hide” a person, a vehicle, a ship, spacecraft, even buildings. The material is said to be inexpensive and paper-thin and does not require a power source. The manufacturer has released over 100 minutes of impressive footage of the material in action.
Active Camouflage technology
Many Active camouflage prototypes have been developed with varying successes.. In 2003 researchers at the University of Tokyo under Susumu Tachi created a prototype active camouflage system using material impregnated with retroreflective glass beads. The viewer stands in front of the cloth viewing the cloth through a transparent glass plate. A video camera behind the cloth captures the background behind the cloth.
A video projector projects this image on to the glass plate which is angled so that it acts as a partial mirror reflecting a small portion of the projected light onto the cloth. The retroreflectors in the cloth reflect the image back towards the glass plate which being only weakly reflecting allows most of the retroreflected light to pass through to be seen by the viewer. The system only works when seen from a certain angle.
Phased-array optics (PAO) would implement active camouflage, not by producing a two-dimensional image of background scenery on an object, but by computational holography to produce a three-dimensional hologram of background scenery on an object to be concealed. Unlike a two-dimensional image, the holographic image would appear to be the actual scenery behind the object independent of viewer distance or view angle.
Octopus-Inspired Camouflage Sheet Developed By US, Chinese Research Team
Drawing inspiration from the color-changing capabilities of cephalopod skin, researchers have developed a new camouflage sheet capable of quickly reading its environment and adapting to mimic its surroundings. The technology, known as an optoelectronic camouflage system, is based on the ability of the octopus, squid and cuttlefish to alter their appearance to hide from predators and as a way to issue warnings. In fact, in addition to changing color, the creatures can alter the shape and texture of their skin, said National Geographic’s Ed Yong. “No man-made technology comes close” to matching the transforming talents of cephalopods, Yong said.
Rogers explained that he and his colleagues are working to develop adaptive sheets that can wrap around solid objects and change their appearance – technology that could allow military vehicles to automatically camouflage themselves, or clothing that can change its color based on current lighting conditions. Lead investigators Cunjiang Yu, assistant professor of mechanical engineering at the University of Houston, and John Rogers of the Beckman Institute for Advanced Science at the University of Illinois at Urbana-Champaign have developed a prototype that currently works in black and white, with shades of gray.
However, Yu said in a statement that the technology could be enhanced to operate in the full color spectrum. The device has a flexible skin comprised of extremely thin layers of semiconductor actuators, switching components and light sensors with inorganic reflectors and organic color-changing materials that combine to allow it to autonomously color-match its background. The three-layer design of the device was copied from the skin of the marine animals, as they have a top layer that contains the colors, a middle layer that drives the color changes, and a lower layer that senses the background patterns to be copied.
In comparison, the camouflage system is a 16-by-16 grid of squares, each of which is comprised of multiple layers, Yong explained. The top one contains heat-sensitive dye that can change color from black at room temperature to colorless at 47 degrees Celsius and back again. The next layer is a thin piece of silver used to create a bright white background, and the one below that heats the dye and controls the color. The final layer contains a light-detector in one corner, and each of the layers above it have notches removed from their corners to allow this instrument to always view the surrounding environment. The device also possesses a flexible base, allowing it to bend and contract without breaking.
“So, the light-detectors sense any incoming light, and tell the diodes in the illuminated panels to heat up,” Yong explained. “This turns the overlying dye from black to transparent. These pixels now reflects light from their silver layer, making them look white. ”
Color Changing Materials
There are a range of colour changing materials that have found use in commercial products such as ophthalmic lenses, toys (hypercolour), thermometers, and many others. These materials can be classified into two major groups – as active or passive materials depending on how the change of the colour is activated. The passive colour change materials, such as photochromic or thermochromic materials react to the changes in environmental parameters, such as ultraviolet (UV) radiation level and temperature, respectively, while active materials, can be switched on and off on demand. One group of active materials is electrochromics. They can be found in a form of a thin film or a suspension, and they range from inorganic materials (eg. tungsten oxides or vanadium oxides) to
organic materials such as viologens or conducting polymers.
Some of the electrochromic materials (inorganic and viologen based) have already been commercialised and can be found in high-end automotive dimming interior rear view mirrors (Gentex corporation) or in the Boeing 787 Dreamliner windows. However, they are limited in their switching speed and high power consumption, where to reach full contrast it takes approximately 60 seconds, and the electric potential must be applied and held to maintain the colour state. Also, viologen based electrochromics are limited to the colour
tones of blue and grey.
Another group of electrochromic materials are conducting polymers. These materials present several promising properties. They require low voltage to switch, offer colour memory effect (they retain their switched colour without a continuously applied voltage) and they have switching speeds in the range of seconds. Several chemistries of conducting polymers have been developed and they range from polyanilines, polythiophenes, polypyrroles and several other derivatives. These materials can produce a wide range of
colour tones we find closely suited to those used for military concealment.
Researchers creating active or dynamic camouflage materials that auto-matches surroundings
Cephalopods—which include octopuses, squid, and cuttlefish—are masters of disguise. These amazing sea creatures change texture, pattern and colour in milliseconds in response to new backdrops, thanks to chromatophore organs or tiny pigment sacks inside their skin. By expanding or contracting their muscles, they can control how much light bounces off these pigments and change their colours. Researchers have been trying to match their skills with varying success.
In a paper published in Feb 2018, in Advanced Optical Materials, Deravi’s group describes its work in isolating the pigment granules within these organs to better understand their role in color change. The researchers discovered these granules have remarkable optical qualities and used them to make thin films and fibers that could be incorporated into textiles, flexible displays, and future color-changing devices. Deravi’s lab collaborated with the U.S. Army Natick Soldier Research, Development, and Engineering Center for the study.
By removing individual pigment particles from the squid, Deravi was able to explore the breadth of their capabilities as static materials. One particle is only 500 nanometers in size, which is 150 times smaller than the diameter of a human hair. Deravi’s team layered and reorganized the particles and found they could produce an expansive color pallet. “We’re showing these pigments are a powerful tool that can produce ultra-thin films that are really rich in colors,” Deravi said.
Her team also discovered the pigments can scatter both visible and infrared light. This enhances brightness and light absorption and affects how a final color is perceived. And when Deravi engineered a system that included a mirror—mimicking the layout of organs that squids have naturally—she was able to further enhance the perceived color through scattering light through and off the granules. This process could potentially be replicated on functional materials like solar cells to increase the absorption of sunlight, Deravi said.
“From a scientific and technical engineering perspective, understanding how light scattering affects color is very important, and this is an exciting new development in the field of optics in biology,” said Richard Osgood, a collaborator from the U.S. Army Natick Soldier Research, Development, and Engineering Center. “This is an unusual harnessing of optics and physics knowledge in scattering to understand biological systems.”
Engineers and professors over at MIT are crafting dynamic, flexible materials that mimic the responsive behavior of cephalopod skin (that’s octopuses, cuttlefish, and squid to you), animals which are able to change color and pattern to blend into their surroundings. Although the durable technology could also be used for various electronics, it’s intended for the military, after attempts to design a single pattern that worked in all terrains failed spectacularly, to the tune of billions
In 2016, Scientists University of Illinois and the Massachusetts Institute of Technology (MIT) made significant steps towards mimicking this process, which they call visual appearance modulation, with a new material. One side of the material contains thousands of tiny light-sensitive cells that can detect surrounding colours. Electrical signals then trigger the top layer to imitate those colours by using heat-sensitive dyes.
Engineering professor Xuanhe Zhao, at MIT, said: ‘I have high hopes for its use in military camouflage. At the moment the military spends millions of dollars developing new camouflage patterns but they’re all static right now, they don’t change. If you put a pattern designed for the forest into the desert, it is not going to function.
‘Dynamic camouflage would allow soldiers and their vehicles to adapt to their surroundings instantly.’ The tests by 3 Rifles and American troops of camouflage material that is ready for use now against enemies such as Islamic State and the Taliban took place earlier this year at the US Army’s centre for experimental warfare techniques at Fort Benning, Georgia. During the trials, British snipers used Vatec – which can be moulded into shapes to match mountainous terrain – to build hideaways on a mock battlefield. In 2014, Scientists from the Massachusetts Institute of Technology (MIT) and Duke University in the US reported to have developed a stretchy, skin-like synthetic material that takes us a step closer to invisbility-cloak-like camouflage.
The material was inspired by cephalopods, the class of animals containing the very-well-camouflaged octopuses, squids and cuttlefish. The new material acts in a similar way, as Sarah Zhang explains for Gizmodo. The polymer has dyes embedded in it, and when voltage is applied to the material it causes the polymer to crease up, changing its texture and colour. This means it can immediately become fluorescent red or bumpy, and even change its pattern, as shown in the images above.
“The texturing and deformation of the elastomer [the polymer that makes up the material] further activates special mechanically responsive molecules embedded in the elastomer, which causes it to fluoresce or change colour in response to voltage changes,” said Stephen Craig, one of the lead researchers from Duke University, in a press release. “Once you release the voltage, both the elastomer and the molecules return to their relaxed state — like the cephalopod skin with muscles relaxed.”
‘Invisibility’ Material Offers Thermal Camouflage
Gorodetsky led the development of the adaptive camouflage materials that change their infrared reflectance on demand, enabling the surface to acquire desired – and potentially deceiving – thermal signatures when visualized under an infrared camera. After being stretched or electrically triggered, the material’s thin swatches quickly change heat reflectance, smoothing or wrinkling their surfaces in under a second. The modulation of apparent temperatures enables an invisibility to infrared night-vision tools. “It goes from wrinkled and dull to smooth and shiny, essentially changing the way it reflects the heat,” said Gorodetsky of the material.
“Essentially, you start out with a surface that’s wrinkled. The wrinkles are tens to hundreds of microns scale, and then you flatten that surface. In those two states is where you have the differences in how the material reflects heat or infrared light.” In the flattened state, the material reflects the heat right back at you. In the wrinkled state, the material scatters the heat, so it doesn’t come right back at the source, or at a camera, that’s looking at heat reflection. Being able to go between those two states is what gives these adaptive properties to the material. When you look at that surface under an infrared camera, those two states will look very different and they’ll have very different apparent temperatures. That effectively lets the material reappear and disappear under an infrared camera.
The camouflage aspect is one, for example, for security applications, but there are many common technologies that rely on controlling thermal radiation. For example, you could create windows on buildings that in one state might reflect heat, but in another state might let it in to maintain the temperature of the building.
The robot uses nanowires that helps it change colour instantly, reported in August 2021
A group of researchers from South Korea have created a robot that is able to change its colour like a chameleon — known to possess the remarkable ability to adjust the colour of its skin to match the surface it is on and blend with the surroundings. The breakthrough research has paved the way for a new high-resolution artificial camouflage technology that can be widely used, including for military and espionage purposes. It can increase the survivability of military equipment and personnel from enemy fires. Previous attempts at artificial camouflage relied on devices with tiny channels to control the flow of fluids inside, but this project took a fully electric approach.
The researchers said that they used colour sensors, nanowire wires, and thermochromic materials —change colour when heated or cooled — to create multiple skin patterns that allowed the robot to change colours almost instantly. The study has been published in the journal Nature Communications. Seung Hwan Ko, a professor at Seoul National University and one of the authors of the study, told MIT Technology Review that the most challenging part was getting the colour transition speeded up to create an appearance of natural behaviour. Here, nanowires, which heat up quickly, were useful. These wires would warm the artificial skin very fast to let the robotic skin change colour.
The nanowires also were useful in creating simple patterns to give shape to the chameleon robot. However, as the technology is dependent on colour, it doesn’t work as well in extreme cold. Also, the development of an artificial camouflage at a complete device level remains a vastly challenging task. But Hwan Ko hopes the research will have a wider impact, more than just military uses, like in the fields of transportation, beauty, and fashion. This technology can help future cars to adapt their colours to stand out or even we can see colour-changing clothes.
Light-driven dynamic surface wrinkles for adaptive visible camouflage
In a new study published in the journal Proceedings of the National Academy of Sciences, a team of researchers has designed a new kind of camouflage technology that can transform someone’s appearance using only light. Borrowing from the biology of cephalopods, this light-driven technology works by creating and relaxing wrinkles in a colored film to scatter color information.
To create the animal-like “skin” of their camouflage tech, the researchers created a sandwich of two different film types: a rigid polymer film and a soft substrate layer mixed with pigments. This soft, pigmented layer expands and contracts when struck with light waves, and the “mismatch” between the states of these two layers creates reversible wrinkles in the skin. From there, it was a simple trick of optics — the science of scattering light — that determined whether or not the skin appeared colorful or hidden. When all scrunched up, the team found that the light was strongly scattered off the surface. This is likely because there was more surface area to scatter off of — think of light scattering of a cut diamond versus flat glass. In this wrinkled state, the skin showed vibrant colors.
“To date, many adaptive camouflage materials and systems have been reported,” the authors write. “However, most dynamic camouflage systems work in active form and require extra mechanical or electric stimuli and even external sensors,” they continue. “These requirements increase the design complexity and mass, leading to clumsiness and an awkward appearance. Moreover, high supply voltages increase the energy consumption.” Instead of relying on extra power supplies or sensors, this team’s technology can work using just sunlight.
“Camouflage enables a device or a robot to seamlessly blend into its environment for effective environment and species monitoring,” the authors write. “[Additionally,] reconnaissance and anti-reconnaissance play an important role in target survivability on the battlefield. Camouflage helps the military objects to avoid detection by the enemy, thus resulting in fewer casualties.”
In addition to its military applications, the authors write that this technology could also have consumer tech applications including smart displays, information storage, and anticounterfeiting technology.
European Commission looking for Innovative technologies for adaptive camouflage (June 2022)
The adaptation of the camouflage characteristics to the conditions, such as encountered sensors, environment and threat level, could bring this protection to a new level. Both the performance of the adaptive camouflage and material characteristics, including its passive properties (e.g., fire/electric shock protection and camouflage), will influence the impact of this technology on military capabilities. An important measure to protect soldiers and military platforms is camouflage in a wider spectral range, also including radar frequency bands
At the same time, available military and commercial sensors, drones, detectors and cameras in combination with sophisticated signal or image processing and analysing software algorithms (such as artificial intelligence-based routines) increase the probability to detect, to recognize or to identify such conventionally camouflaged objects. An increasing threat consists of (more) affordable high-tech sensors, airborne (e.g., drones) and ground based, operating in the various spectral bands including emerging sensor technologies (such as lasers scanning and quantum) and multi and hyperspectral sensors.
Improved and new Camouflage, Concealment, Deception & Obscurant (CCD&O) solutions and operating procedures are required to prevent land systems (including their weapons) to be detected, identified or their intentions disclosed. Potential countermeasures include passive camouflage, mobile systems, weapons, active camouflage, including smart materials, deception methods, obscurants, and deceptive technologies.
A promising contribution to this challenge is adaptive camouflage techniques and devices that are able to adapt their signatures to the background, to the surveillance sensors (mainly when active), different weather and daytime conditions and threat level hence reducing the ranges of detection, tracking, recognition and identification increasing the survivability of soldiers and platforms. Military platforms or soldiers equipped with adaptive camouflage measures are able to change the signature and to adapt it to the actual background or to deceive sensors in different spectral bands. In order to provide protection against future sensor technologies, development of new materials and concepts have to be investigated. The current development of electromagnetic detection tools like Foliage Penetration Reconnaissance, Surveillance, Tracking and Engagement Radar pinpoints a need for wider spectral range protection, also including radar frequency bands, to protect moving soldiers or military platforms under trees. A combination of camouflage in the optical and radar spectral bands will ensure the highest level of protection, reducing the risk of being targeted.
In that sense and in line with both ‘Ground Combat Capabilities’ CDP priority and ‘Soldier Systems’ CARD Focus Area, this topic aims to push the undergoing technological effort addressing adaptive camouflage for protection of land systems.
In particular – and in compliance with European Defence Agency (EDA)’s Overarching Strategic Research Agenda (OSRA) results, including TBB3 [3] “Passive and active protection for Land Systems” and TBB87 “Camouflage and Signature Management Technologies” – this topic will contribute for closing the technical gaps directly related with the following capabilities:
Upgrade, modernize and develop Land platforms to adapt to operational environment – upgrade of current and development of next generation’s armoured platforms.
Enhance protection of forces.
Improve individual soldier equipment.
Scope
The main scope is to investigate suitable adaptive innovative camouflage techniques, taking also into account usability, and to demonstrate this with a technology demonstrator in real applications. Especially the problem of a good adaptation to the background and to the observing sensors in different spectral bands should be at the heart of the activities. Proposals should address the development of new concepts, technological blocks, sub-systems and/or systems. Technologies for commercial, civil applications and concepts of previous projects that have been publicly presented should be taken into account.
In order to understand the prioritisation of adaptive camouflage techniques, the activities should contain a threat analysis, which explores and ranks risk areas on military platforms or soldiers and ranks spectral range threats to be treated. These considerations should reflect night-time and daytime scenarios, situations of degraded visual environment given in woodland, arid and snow situation. The abovementioned threat analysis should also contain reference on the physics of camouflage for each spectral band.
The activities shall further focus mainly on research on state-of-the-art and innovative adaptive camouflage techniques and devices in the different optical and radar spectral bands, on arranging and combining them in a common structure (layers, mosaic), on realizing a demonstrator (rigid panel display, elastic shield or flexible textile) and on testing and assessing it. The aim is to have the ability to change the signature (intensities and patterns) in different spectral bands at the same time without deteriorating the signature in any other spectral band. A concept and proposal to develop a self-adapting closed loop with the help of sensors (either embedded or as part of the material) detecting the surrounding environment and its own signature should also be planned. Materials for signature management in spectral bands listed in footnote 16 not deemed as threats should be studied on a more basic research level (TRL 1-4). Moreover, a development of bi-recyclable textiles and flexible elements (e.g., smart glass, optical fibres, etc,) with widest possible anti-radar properties should be investigated.
The adaptive camouflage techniques considered should address the integration with the platform or soldier C4I technology and should consider power source appropriate for the platform or soldier energy budget.
References and Resources also include:
http://www.bbc.com/future/story/20140915-is-this-the-ultimate-camouflage
https://en.wikipedia.org/wiki/Active_camouflage
https://phys.org/news/2018-02-squid-skin-solution-camouflage-material.html
https://www.techbriefs.com/component/content/article/tb/stories/blog/28976
https://www.inverse.com/innovation/creating-camouflage-using-sunlight
