Camouflage Effect Research Articles

Metamaterial-inspired infrared electrochromic devices with wideband microwave absorption for multispectral camouflage

Infrared (IR) electrochromic devices, capable of dynamically controlling thermal radiation, hold promising applications in adaptive camouflage. However, the strong microwave reflective properties inherent in the device’s electrodes present a significant challenge, rendering them susceptible to radar detection and weakening their camouflage effect. Inspired by the remarkable electromagnetic control capabilities of metamaterials, the integration of frequency selective surfaces into IR electrochromic devices is proposed to address this multispectral compatibility challenge. The designed integrated metadevices simultaneously exhibit large and reversible IR emissivity tunability (Δε≥0.55 at 3–5 μm, Δε≥0.5 at 7.5–13 μm) and wideband microwave absorption (reflection loss ≤−10 dB at 8.5–18 GHz). Furthermore, the monolithic integrated design of the shared barium fluoride substrate offers a simple device architecture, while careful design considerations mitigate coupling between IR electrochromism and microwave wideband absorption. This work introduces opportunities for the development of multispectral adaptive camouflage systems, offering potential advancements in concealment technology.

Construction of diverse adaptive camouflage nets based on soluble yellow-to-green switching electrochromic materials

The potential application of electrochromic (EC) materials and devices as adaptive camouflage in diverse environments requires further investigation. In this study, we aimed to enhance the camouflage effect of electrochromic devices (ECDs) by developing innovative EC camouflage nets. Three soluble EC materials (FTP, FEP and FBP) were synthesized by incorporating phenothiazine and ProDOT with different donors through direct(hetero) arylation polymerization. Due to the fine-tuning of the energy gap, the three materials exhibit yellow, yellowish-brown and reddish-brown colors in their neutral states, respectively. Particularly, FTP and FEP can switch between different yellow-to-green with superior EC performance. Furthermore, FTP-PEDOT and FEP-PEDOT ECDs were constructed. Notably, the FEP-PEDOT ECD demonstrated enhanced EC performance, characterized by a more noticeable yellow-to-green switch, faster switching times and improved cycle stability. To meet the adaptability for multi-environmental camouflage and wearable applications, we created diverse camouflage patterns using the mask-spray technique and developed three types (“stripe”/ “cross stripe”/ “block”) camouflage net ECDs. This study offers a comprehensive approach for developing adaptive camouflage nets tailored to diverse real combat settings.

A novel type of weather resistant jungle camouflage coating based on hydrotalcites with ability to highly accurate simulate water peaks of the NIR spectrum

The existing jungle camouflage coatings cannot accurately simulate the near-infrared spectral characteristics of water peaks in the 1400–1900 nm region of green vegetation. Compared with the peak area of vegetation water absorption, the smaller water valley area of camouflage coatings is the most serious problem faced by camouflage coatings. This article proposes a new camouflage coating based on hydrotalcites, and the camouflage coating was characterized using XRD, FT-IR, TG-DTA, and SEM equipment. The experimental results show that the spectral water valley area of the camouflage coating is close to that of the vegetation, and the similarity calculation with the vegetation spectrum reaches 95.62%. Especially, the coating has long-term weather resistance, which can accurately simulate the near-infrared spectral characteristics of green vegetation. The hyperspectral imaging results of the camouflage coating confirm that the prepared camouflage coating has a camouflage effect similar to that of green vegetation. This work innovatively proposes a new type of camouflage coating based on hydrotalcites, providing a new research direction for the development of vegetation camouflage.

Treatment of Class III Malocclusion with Open Bite and Macroglossia Using an Anterior Loop

General Background: Class III malocclusion is a prevalent dental anomaly characterized by the anterior positioning of the mandible relative to the maxilla, posing functional and aesthetic challenges. Specific Background: This condition may present with additional complexities such as dental crowding, open bite, and macroglossia, complicating the orthodontic treatment approach. Knowledge Gap: While conventional treatment modalities include orthognathic surgery and growth modification, there is limited documentation on the efficacy of orthodontic camouflage in non-surgical settings, particularly in adults with completed growth. Aims: This study aims to evaluate the effectiveness of orthodontic camouflage using anterior stainless steel loops in managing dentoskeletal Class III malocclusion accompanied by anterior open bite and macroglossia, without premolar extraction. Results: Over a 7-month treatment period, significant corrections in overjet, overbite, and molar relationship were achieved, demonstrating the potential of this approach as a non-surgical alternative. Novelty: This research introduces a modified technique involving stainless steel wire with specific loop placements, contributing to the orthodontic management strategies for complex Class III cases. Implications: The findings support the broader application of camouflage techniques in orthodontic practice, offering a viable option for patients opting out of surgery and highlight the need for further studies to optimize and validate such approaches.Highlights: Efficiency of Camouflage: Shows how orthodontic camouflage can effectively treat complex Class III malocclusion without surgery. Novel Technique: Introduces a new method using stainless steel loops in wires to enhance treatment outcomes. Clinical Implications: Expands non-surgical treatment options in orthodontics, offering viable alternatives to surgery. Keywords: Class III Malocclusion, Orthodontic Camouflage, Open Bite, Macroglossia

Characterization of Near Infrared-Dye Colored Fabrics Using Hyperspectral Imaging.

Near-infrared (NIR) dyes have a unique ability to interact favorably with light in the NIR region, which is particularly interesting where stealth and camouflage are paramount, such as in military uniforms. Characterization of cotton fabric dyed with NIR-absorbing dyes using visible-NIR (Vis-NIR) and short-wave infrared (SWIR) hyperspectral imaging was done. The aim of the study was to discern spectral changes caused by variations in dye concentration and dyeing temperature as these parameters directly influence color- and crocking-fastness of fabrics impacting the camouflage effect. The fabric was dyed at three concentrations (2.5, 5, and 10%) and two dyeing temperatures (55 °C and 85 °C) and principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were performed on the spectra to discriminate the fabrics based on dye concentrations. The PCA models successfully segregated the fabrics based on the dye concentration and dyeing temperature, while PLS-DA models demonstrated classification accuracies between 75 and 100% in the Vis-NIR range. Spectra in the SWIR region could not be used to detect the differences in the concentrations of the NIR dyes. This finding is promising, as it aligns with the objective of creating NIR-dyed camouflage fabrics that remain indistinguishable under varying dye concentrations. These results open possibilities for further exploration in enhancing the stealth capabilities of textiles in military applications.

Role of body size and shape in animal camouflage.

Animal camouflage serves a dual purpose in that it enhances both predation efficiency and anti-predation strategies, such as background matching, disruptive coloration, countershading, and masquerade, for predators and prey, respectively. Although body size and shape determine the appearance of animals, potentially affecting their camouflage effectiveness, research over the past two centuries has primarily focused on animal coloration. Over the past two decades, attention has gradually shifted to the impact of body size and shape on camouflage. In this review, we discuss the impact of animal body size and shape on camouflage and identify research issues and challenges. A negative correlation between background matching effectiveness and an animal's body size has been reported, whereas flatter body shapes enhance background matching. The effectiveness of disruptive coloration is also negatively correlated with body size, whereas irregular body shapes physically disrupt the body outline, reducing the visibility of true edges and making it challenging for predators to identify prey. Countershading is most likely in larger mammals with smaller individuals, whereas body size is unrelated to countershading in small-bodied taxa. Body shape influences a body reflectance, affecting the form of countershading coloration exhibited by animals. Animals employing masquerade achieve camouflage by resembling inanimate objects in their habitats in terms of body size and shape. Empirical and theoretical research has found that body size affects camouflage strategies by determining key aspects of an animal's appearance and predation risk and that body shape plays a role in the form and effectiveness of camouflage coloration. However, the mechanisms underlying these adaptations remain elusive, and a relative dearth of research on other camouflage strategies. We underscore the necessity for additional research to investigate the interplay between animal morphology and camouflage strategies and their coevolutionary development, and we recommend directions for future research.

Femtosecond laser-textured superhydrophilic coral-like structures spread AgNWs enable strong thermal camouflage and anti-counterfeiting

Modulating the thermal emission of a material in the infrared (IR) range can be essential for various practical applications such as smart textiles, camouflage, and anti-counterfeiting. Although many different materials or structures have been proposed, the complex manufacturing processes are still hindering their widespread use. Herein, a facile femtosecond laser processing technology and a drop-coating method are introduced to form a patternable low emissivity film. Laser-treated polyimide films resulted in superhydrophilic structured surfaces that are uniformly coated with silver-nanowires (AgNWs) in aqueous solutions for low emissivity surfaces. Furthermore, the emissivity of the samples is as low as ∼0.2 without deterioration over 800 bending-releasing cycles. The as-prepared films also display good thermal camouflage properties, namely, the films reduced the thermal radiation temperature of an object by 35.8 °C when the object temperature was ∼69.1 °C. Additionally, this IR camouflage effect of the AgNWs coated samples shows excellent stability even in harsh environments such as immersion in water, acid, alkali, and salt solution and applied voltage. We also show that information encryption was possible by adjusting the amount of AgNWs. The design of this programmable patterned low emissivity film indicates an idea for the thermal camouflage and anti-counterfeiting technology, which can carry more abundant application scenario and disguise them more complex and sophisticated.

Research on military targets camouflage effect rating based on background anomaly detection and deep transfer features learning

Manual evaluation of military target camouflage often fails to fully capture human visual characteristics. This paper introduces a method for intelligent camouflage feature extraction and effect evaluation using deep neural networks. Firstly, military target and background datasets are constructed, with annotation methods optimized through perceptual experiments. A GANomaly model for background anomaly detection and a transfer learning feature model are developed. These models evaluate data similarity to background and target features to categorize camouflage into three levels. PCA dimensionality reduction and RFE screening identify final features. Two logistic regression models are then combined to create a grading model. In experiments, the GANomaly model was trained and optimized, achieving 86.8% accuracy in distinguishing level 1 from non-level 1 camouflage using 28-dimensional features. Among three transfer models, the MobileNetV2 model identified 33-dimensional features with 85.1% accuracy in distinguishing level 3 from non-level 3 camouflage. Combined, the models reached an 84.3% grading accuracy on the test set, with Micro and Macro average AUC values of 0.939 and 0.945, respectively. This performance surpasses that of BP network models and linear models based on manual features, as well as metrics like SSIM, UIQI, MSE, and PSNR. The results indicate that the models effectively align with human annotations and can reliably assess military target camouflage levels.

Reversible image hiding with super-resolution behavior camouflage effect

Reversible image hiding with super-resolution behavior camouflage effect

Research on the Evaluation of Target Camouflage Effect in Visible Spectrum Based on Similarity

Research on the Evaluation of Target Camouflage Effect in Visible Spectrum Based on Similarity

Assessing target optical camouflage effects using brain functional networks: A feasibility study

Brain functional networks model the brain's ability to exchange information across different regions, aiding in the understanding of the cognitive process of human visual attention during target searching, thereby contributing to the advancement of camouflage evaluation. In this study, images with various camouflage effects were presented to observers to generate electroencephalography (EEG) signals, which were then used to construct a brain functional network. The topological parameters of the network were subsequently extracted and input into a machine learning model for training. The results indicate that most of the classifiers achieved accuracy rates exceeding 70%. Specifically, the Logistic algorithm achieved an accuracy of 81.67%. Therefore, it is possible to predict target camouflage effectiveness with high accuracy without the need to calculate discovery probability. The proposed method fully considers the aspects of human visual and cognitive processes, overcomes the subjectivity of human interpretation, and achieves stable and reliable accuracy.

Ontogeny of color development in two green-brown polymorphic grasshopper species.

Many insects, including several orthopterans, undergo dramatic changes in body coloration during ontogeny. This variation is particularly intriguing in gomphocerine grasshoppers, where the green and brown morphs appear to be genetically determined (Schielzeth & Dieker, 2020, BMC Evolutionary Biology, 20, 63; Winter etal., 2021, Heredity, 127, 66). A better understanding of how these color morphs develop during ontogeny can provide valuable insights into the evolution and ecology of such a widespread color polymorphism. Here, we focus on the color development of two green-brown polymorphic species, the club-legged grasshopper Gomphocerus sibiricus and the steppe grasshopper Chorthippus dorsatus. By following the color development of individuals from hatching to adulthood, we found that color morph differences begin to develop during the second nymphal stage, are clearly defined by the third nymphal stage, and remain stable throughout the life of an individual. Interestingly, we also observed that shed skins of late nymphal stages are identifiable by color morphs based on their yellowish coloration, rather than the green that marks green body parts. Furthermore, by assessing how these colors are perceived by different visual systems, we found that certain potential predators can chromatically discriminate between morphs, while others may not. These results suggest that the putative genes controlling color morph are active during the early stages of ontogeny, and that green color is likely composed of two components, one present in the cuticle and one not. In addition, the effectiveness of camouflage appears to vary depending on the specific predator involved.

Acoustic camouflage increases with body size and changes with bat echolocation frequency range in a community of nocturnally active Lepidoptera.

Body size is an important trait in predator-prey dynamics as it is often linked to detection, as well as the success of capture or escape. Larger prey, for example, often runs higher risk of detection by their predators, which imposes stronger selection on their anti-predator traits compared to smaller prey. Nocturnal Lepidoptera (moths) vary strongly in body size, which has consequences for their predation risk, as bigger moths return stronger echoes for echolocating bats. To compensate for increased predation risk, larger moths are therefore expected to have improved anti-predator defences. Moths are covered by different types of scales, which for a few species are known to absorb ultrasound, thus providing acoustic camouflage. Here, we assessed whether moths differ in their acoustic camouflage in a size-dependent way by focusing on their body scales and the different frequency ranges used by bats. We used a sonar head to measure 3D echo scans of a total of 111 moth specimens across 58 species, from eight different families of Lepidoptera. We scanned all the specimens and related their echo-acoustic target strength to various body size measurements. Next, we removed the scales covering the thorax and abdomen and scanned a subset of specimens again to assess the sound absorptive properties of these scales. Comparing intact specimens with descaled specimens, we found almost all species to absorb ultrasound, reducing detection risk on average by 8%. Furthermore, the sound absorptive capacities of body scales increased with body size suggesting that larger species benefit more from acoustic camouflage. The size-dependent effect of camouflage was in particular pronounced for the higher frequencies (above 29 kHz), with moth species belonging to large-bodied families consequently demonstrating similar target strengths compared to species from small-bodied families. Finally, we found the families to differ in frequency range that provided the largest reduction in detection risk, which may be related to differences in predation pressure and predator communities of these families. In general, our findings have important implications for predator-prey interactions across eco-evolutionary timescales and may suggest that acoustic camouflage played a role in body size evolution of nocturnally active Lepidoptera.

Long‐Term Infrared Stealth by Sandwich‐Like Phase‐Change Composites at Elevated Temperatures via Synergistic Emissivity and Thermal Regulation

AbstractThe rapid development of infrared surveillance technologies has attracted great attention for scientists to design advanced functional materials with prominent infrared stealth and thermal camouflage effectiveness. In the current study, a sandwich‐like functional composite based on a crosslinked polyimide aerogel, a meso‐erythritol (mE)‐based phase‐change composite, and an MXene film has been developed to achieve long‐term thermal camouflage at elevated temperatures. In this composite system, the lower aerogel layer can act as a barrier to insulate heat transfer through its layer‐stacking structure under ultralow directional thermal conduction. The introduction of the middle phase‐change composite layer ensures that the composite system obtains a dynamical temperature‐regulation capability through sensible and latent heat absorption of mE as a phase change material, while the upper MXene layer provides a very low emissivity surface for the system. As a result, the developed composite achieves a significant reduction in the thermal radiation temperature of a high‐temperature target. Moreover, the MXene film exhibits good electromagnetic interference shielding effectiveness, making the sandwich‐like composite obtain a thermal camouflage capability in various complicated scenarios. This work provides a promising approach for the design of advanced functional materials to realize long‐term infrared stealth and thermal camouflage of high‐temperature targets in security protection and counter‐surveillance.

Identification of morphostructures by utilizing Knickpoint Ranks, a method to avoid the camouflage effect in knickpoint analysis

Knickpoints are relief features characterized by a convex-up abrupt change in the equilibrium profile of a given river. In the field they can be recognized as rapids or waterfalls. Their presence indicate geological conditions or processes that modify erosive rates, such as contrasting lithologies, base-level changes, or active structures, and, therefore, especially relevant in tectonic geomorphology studies. The computation of knickpoints for classification purposes is made dividing the Slope-Extension Ratio (RDE) by the Total Slope-Extension Ratio (RDT), which are derived from the Stream-Gradient index (SL). Traditionally, the classification of knickpoints has been treated in two ways, (1) by the simple division into first and second order, according to a limit value of RDE/RDT of 10, and (2) by the statistical division of values into classes, mainly with natural breaks. Recent studies have used both divisions and correlated the RDE/RDT values with the size of the knickpoints in the field. However, there are studies on morphometric analysis that point to the existence of gaps that occur in specific cases, such as the so-called knickpoint camouflage. In order to eliminate these gaps and with the aim of improve the classification technique, we propose the determination of fixed intervals of distribution of knickpoints which, based on the division according to the RDE/RDT values, use the strengths of the statistical divisions as a means to define limits of RDE/RDT values. The objective of this methodological development is to prevent errors during the classifications as well as to facilitate the interpretation of the obtained knickpoints. The new classification method was applied in 20 hydrographic basins with their RDE/RDT values checked in 44 knickpoints in the field. The analyses carried out point to the coherence of the new proposed classification and confirm the effectiveness of both the fixed intervals and the tools used in the cartography of knickpoints.

The effectiveness of microneedling and cosmetic camouflage in the treatment of vitiligo

BACKGROUND: Treatment of vitiligo is one of the most difficult problems in dermatology. Despite the availability of various safe and effective methods of treatment, there are problems with combining and correctly applying techniques for the most effective result. Vitiligo has an impact on the psycho-social aspects of patients' daily life. This makes it necessary to use additional techniques, such as cosmetic camouflage to improve the quality of life of patients with vitiligo.
 AIM: to assess the effectiveness of microneedling and cosmetic camouflage for the treatment of vitiligo.
 MATERIALS AND METHODS: The study included 78 people with vitiligo aged 2846 years. At the first stage of the study, 49 patients underwent microneedling in combination with ultraviolet B therapy and local tacrolimus. The subjects of the control group (n=29) were affected only by ultraviolet B therapy and tacrolimus. Phototherapy with ultraviolet B rays of 311 nm was carried out according to the method of 3-fold irradiation per week (Monday, Wednesday, Friday) with an initial dose of 0.05 J/cm2. 0.1% tacrolimus ointment was applied twice a day during the course of therapy. The treatment lasted for 25 months; 2 courses of 2 months were carried out with a break of 3 months (in total 5 months). On average, for therapeutic effect (complete or partial repigmentation), patients received 6064 sessions. Patients of the studied groups underwent a comparative analysis of repigmentation 2 and 5 months after treatment. At the second stage of the study, patients after microneedling were divided into the main group (n=33) and the comparison group (n=16). The subjects of the comparison group underwent cosmetic camouflage of vitiligo sites. Before and after treatment, the dermatological index of quality of life was determined for patients.
 RESULTS: After 1 month from the start of treatment, 67.4% of patients after microneedling and 6.1% of patients in the control group showed moderate improvement (2650% repigmentation). There was a good improvement with 5175% repigmentation in 26.5% of patients after microneedling. After 5 months from the start of treatment, 67.4% of the subjects after microneedling showed an improvement in repigmentation of more than 51%. It was found that the average indicators of the dermatological quality of life index after treatment in patients of the main group (9.60.3 points) and the comparison group (7.00.3 points) corresponded to the values of "moderate effect of the disease on quality of life" and were significantly (p=0.018) lower than the baseline level (20.80.2 points and 19.91.1 points). This was not determined in the control group (18.20.4 points and 22.40.1 points). In the comparison group, this indicator was significantly (p=0.001) lower in comparison with the scores of other study groups.
 CONCLUSION: The combination of microneedling, ultraviolet B therapy and tacrolimus is an effective method of treating patients with vitiligo. It increases repigmentation and quality of life. Additional cosmetic camouflage improves various aspects of the life of patients with vitiligo.

Habitat geometry rather than visual acuity limits the visibility of a ground-nesting bird's clutch to terrestrial predators.

The nests of ground-nesting birds rely heavily on camouflage for their survival, and predation risk, often linked to ecological changes from human activity, is a major source of mortality. Numerous ground-nesting bird populations are in decline, so understanding the effects of camouflage on their nesting behavior is relevant to their conservation concerns. Habitat three-dimensional (3D) geometry, together with predator visual abilities, viewing distance, and viewing angle, determine whether a nest is either visible, occluded, or too far away to detect. While this link is intuitive, few studies have investigated how fine-scale geometry is likely to help defend nests from different predator guilds. We quantified nest visibility based on 3D occlusion, camouflage, and predator visual modeling in northern lapwings, Vanellus vanellus, on different land management regimes. Lapwings selected local backgrounds that had a higher 3D complexity at a spatial scale greater than their entire clutches compared to local control sites. Importantly, our findings show that habitat geometry-rather than predator visual acuity-restricts nest visibility for terrestrial predators and that their field habitats, perceived by humans as open, are functionally closed with respect to a terrestrial predator searching for nests on the ground. Taken together with lapwings' careful nest site selection, our findings highlight the importance of considering habitat geometry for understanding the evolutionary ecology and management of conservation sites for ground-nesting birds.

Multifunctional Metamaterials with Ultrawideband Wave Absorption and Thermal Camouflage

Objects can be identified based on their distinctive scattering signatures in multiple physical areas such as optics, electromagnetics, and thermotics. To ensure comprehensive stealth and camouflage capabilities, antisense devices with multiphysical field coupling are highly desired. Herein, a multifunctional antisense metadevice that achieves stealth in the microwave band while also generating multiple camouflage images from the original object's position during the heat conduction process is proposed and demonstrated. The metadevice combines both antimicrowave detection and camouflage infrared imaging capabilities, resulting in broadband electromagnetic stealth and thermal camouflage effect. Experimental and simulation results confirm the metadevice's ability to achieve these multifunctional capabilities in temperature‐dependent cases. The development of such multifunctional devices that span physical fields provides new avenues for the design and preparation of multifunctional structures.

Development of Neural Network Recognition Model for Optical Illusion Images

In the battlefield, tank armored vehicles have high mobility, strong defense and stable transportation capabilities, and play a role that cannot be ignored. However, its appearance and camouflage pattern design often have the camouflage effect of geometric optical illusion. The good recognition effect can ensure the safety of soldiers, and also avoid the loss of life and property of the people by accidentally hitting the surrounding houses. Therefore, how to quickly and effectively identify its appearance has become an urgent problem to be solved in the military. In this paper, the outline of the vehicle is disassembled into 12 most representative basic shapes for analysis, using image preprocessing technology, invariant moment feature extraction, and developing a BPNN(back propagation neural network) recognition model, which effectively improves the recognition rate of tank armored vehicles over above 95%.

Camouflage and masking behavior in adult autism.

Autism spectrum disorder (ASD) is characterized by persistent deficits in social communication and social interaction across multiple contexts. Social camouflaging was first shown to be a characteristic of autistic persons, who actively try to disguise and compensate for their autism features in social contexts in an effort to socially blend in better. Recently, an increasing, though still insufficient, number of studies has been conducted on the concept of camouflage; however, different aspect of it, from psychopathology and etiology to its complications and consequences, are not clearly defined. We aimed to systematically review the existing literature on camouflage in autistic adults to describe the correlates of camouflage, motivations for exhibiting camouflage behavior, and the potential impacts of camouflage on the mental health of autistic individuals. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist guidelines to conduct a systematic review. The databases of PubMed and Scopus, and PsycInfo were searched for eligible studies. Studies were published between January 1st, 1980, to April 1st, 2022. We included 16 articles, of which four studies were qualitative and 11 were quantitative. One study used a mix method. The assessment tools used for camouflage, the correlates of camouflage including autism severity, gender, age, cognitive profile and neuroanatomical correlates, reasons for camouflage and the impacts of camouflaging behavior on mental health are discussed in this review. In synthesizing the literature, we conclude that camouflage seems to be more common among females who report more autistic symptoms themselves. There may also be some differences between men and women in reasons of exhibiting it and its neuroanatomical correlates. Further research is needed as to why this phenomenon is more prevalent in females with implications for gender related cognitive and neuroanatomical differences. Effects of camouflage on mental health and daily life measures of individuals such as employment, university graduation, relationship, financial status, and quality of life should be studied with more details in future studies.