Vivid Colors Research Articles

Cross-domain learning for underwater image enhancement

The poor quality of underwater images has become a widely-known cause affecting the performance of the underwater development projects, including mineral exploitation, driving photography, and navigation for autonomous underwater vehicles. In recent years, deep learning-based techniques have achieved remarkable successes in image restoration and enhancement tasks. However, the limited availability of paired training data (underwater images and their corresponding clear images) and the requirement for vivid color correction remain challenging for underwater image enhancement, as almost all learning-based methods require paired data for training. In this study, instead of creating the time-consuming paired data, we explore the unsupervised training strategy. Specifically, we introduce a universal cross-domain GAN-based framework to generate high-quality images to address the dependence on paired training data. To ensure the vivid colorfulness, the color loss is designed to constrain the training process. Also, a feature fusion module (FFM) is proposed to increase the capacity of the whole model as well as the dual discriminator channel adopted in the architecture. Extensive quantitative and perceptual experiments show that our approach overcomes the limitation of paired data and obtains superior performance over the state-of-the-art on several underwater benchmarks in terms of both accuracy and model deployment.

Greek preschoolers drawing the TV of their dreams

This research illustrates how young children conceptualize the image and role of ideal television in their life. Building upon Kress and Van Leeuwen’s (2006) theoretical framework of Visual Grammar, 70 drawings of children from kindergartens of Thessaloniki were analyzed both qualitative and quantitative. Children’s pictorial depictions of their understanding of dream TV suggested they viewed the desirable TV quite close to the traditional TV that has two main aims: entertainment and environmental education. Moreover, the concept of dream TV was closely defined by play both as outdoor activity and organized sports but also toys advertisements. The results of this research revealed that children sketch a quite positive and powerful image of dream TV painted with vivid colors and joyful pictures which has an active role in their lives.

Colors and Learner’s Gender Evoke Different Emotional and Cognitive Effects in Multimedia Learning

The emotional design principle avers that highly saturated warm colors in multimedia learning presentations can elevate affective-motivational, cognitive, and learning outcomes. While warm and achromatic grayscale color tones have been explored extensively, relatively less research examines the effects of cold colors in multimedia learning. This study explores how color tones (warm, cold, and achromatic grayscale) and learners’ gender influence positive emotions, intrinsic motivation, cognitive load, and transfer performance. An online experiment was conducted where learners pursuing IT courses in an Asian university (n=204) engaged with either one of the multimedia learning lessons on distributed denial-of-service attack imbued with (1) a warm color tone, (2) a cold color tone, and (3) an achromatic grayscale color tone. Findings show that the cold color tone was associated with fewer enhanced positive emotion types than the other color tones. Compared to the achromatic grayscale color tone (M=2.38,SD=1.88), significantly higher extraneous cognitive load ratings were observed with the warm color tone (M=3.26,SD=1.96) and the cold color tone (M=3.24,SD=2.18). Following reports by some learners, this could be attributed to the overly vivid and saturated chromatic colors impairing the learners’ visual and cognitive processes, causing them to rate the multimedia learning experience with warm and cold color tones as more difficult than with the achromatic grayscale color tone. Male learners in the warm color tone condition (M=4.93,SD=3.46) performed marginally better on the transfer posttest than male learners in the cold color tone condition (M=3.49,SD=3.45) and male learners in the achromatic grayscale color tone condition (M=3.44,SD=2.69). In contrast, female learners in the warm color tone condition (M=1.75,SD=1.62) performed marginally worse than female learners in the cold color tone condition (M=3.83,SD=3.92) and significantly worse than female learners in the achromatic grayscale color tone condition (M=3.67,SD=2.50). Overall, these results show that gender can shape the effects of warm colors on learning—the warm color tone can enhance male learners’ but stifle female learners’ transfer performance. Moreover, this study aligns with recent studies that colors as an emotional design feature may lead to higher cognitive load ratings. This paper discusses the theoretical and practical implications and submits a future outlook for broadening the research domain.

To realize a variety of structural color adjustments via lossy-dielectric-based Fabry–Perot cavity structure

Abstract Structural colors with tunable properties have extensive applications in surface decoration, arts, absorbers, and optical filters. Planar structures have more advantages over other forms studied to date due to their easy manufacturability. Metal-insulator-metal-based structures are one of the known methods to fabricate structural colors where colors can be tuned mainly by the thickness of the intermediate lossless insulator layer. However, generating colors by MIM structure requires a thin metallic layer on top, and the top metals’ abrasiveness and/or oxidation may degrade the colors quickly. Thus, we propose a lossy dielectric layer to replace the top metallic layer as a solution to ensure the structure’s durability by preventing scratches and oxidation. Herein, CrON/Si3N4/Metal structures have been studied where theoretical investigations suggest that highly saturated colors can be generated in the lossy-lossless dielectric structures. Experimental data validated such simulations by revealing a range of vivid colors. Furthermore, these structures can easily achieve strong light absorption (SLA) even for a thick top layer of ∼100 nm. The colors realized by these structures are appeared due to a combination of the interference effect of the asymmetric Fabry–Perot cavity structure and the absorption rate in the CrO x N1−x layer.

Preparation of Acrylic Yarns with Durable Structural Colors Based on Stable Photonic Crystals.

Structural coloration of photonic crystals (PCs) is considered an ecological and environmental way to achieve colorful textiles. However, constructing PCs with obvious structural colors on traditional flexible yarns is still a great challenge. As a secondary structure that forms textiles, compared with fibers and fabrics, the yarns are rougher, hindering the construction of regular PCs. In this work, the flexible acrylic yarns with vivid structural colors, named PC-based structural color yarns, were prepared by constructing regular PCs via assembling poly(styrene-butyl acrylate-methacrylate) (P(St-BA-MAA)) colloidal microspheres on yarns. Specifically, the properties of P(St-BA-MAA) colloidal microspheres were investigated. The PCs with better structural stability and obvious structural colors were prepared by presetting the acrylic adhesive layer on yarns. Moreover, the color durability and color regulation methods of prepared PC-based structural color yarns were evaluated and discussed. The results showed that the P(St-BA-MAA) colloidal microspheres exhibited even particle sizes, excellent monodispersity, and a typical hard core-soft shell structure. And the glass-transition temperature (T g) of the microspheres was tested to be about 65.6 °C. The cationic acrylate regarded as a pretreatment agent could not only improve the combination between the PC layers and the yarns by acting as a "bridge" but also enhance the structural color effect by smoothing the yarn surface. The results showed that when the mass fraction of cationic acrylate was 3 wt %, the microspheres were beneficial to access regular PCs with obvious structural colors. The PCs with bright structural colors could be constructed on black acrylic yarns, and the colors of yarns were still bright after rubbing and washing tests, indicating that the prepared PC-based structural color yarns have good color fastness. Moreover, the color hue of PC-based structural color yarns could be regulated by adjusting the particle sizes and viewing angles. This study provides strategic support for the structural coloration of flexible materials.

Colorful Image Colorization with Classification and Asymmetric Feature Fusion.

An automatic colorization algorithm can convert a grayscale image to a colorful image using regression loss functions or classification loss functions. However, the regression loss function leads to brown results, while the classification loss function leads to the problem of color overflow and the computation of the color categories and balance weights of the ground truth required for the weighted classification loss is too large. In this paper, we propose a new method to compute color categories and balance the weights of color images. In this paper, we propose a new method to compute color categories and balance weights of color images. Furthermore, we propose a U-Net-based colorization network. First, we propose a category conversion module and a category balance module to obtain the color categories and to balance weights, which dramatically reduces the training time. Second, we construct a classification subnetwork to constrain the colorization network with category loss, which improves the colorization accuracy and saturation. Finally, we introduce an asymmetric feature fusion (AFF) module to fuse the multiscale features, which effectively prevents color overflow and improves the colorization effect. The experiments show that our colorization network has peak signal-to-noise ratio (PSNR) and structure similarity index measure (SSIM) metrics of 25.8803 and 0.9368, respectively, for the ImageNet dataset. As compared with existing algorithms, our algorithm produces colorful images with vivid colors, no significant color overflow, and higher saturation.

Microbial diversity and functional genes of red vinasse acid based on metagenome analysis.

Red vinasse acid has a distinct flavor and a vivid red color that are directly tied to the intricate metabolic activities of microorganisms that produce it. In this study, metagenomic technology was used to mine its functional genes and examine the microbial diversity of red vinasse acid. The findings revealed the identification of 2,609 species, 782 genera, and 63 phyla of microorganisms, and the dominant genus was Lactobacillus. Amino acid metabolism and carbohydrate metabolism were significant activities among the 16,093 and 49,652 genes that were annotated in the evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively. In gluconeogenesis, red vinasse acid encodes 194 genes controlling the transporter protein systems of different sugars and has key enzyme genes that catalyze the conversion of intracellular sugars into glycolytic intermediates. In amino acid flavor formation, red vinasse acid contains 32 control genes for branched-chain aminotransferase (BCAT), 27 control genes for aromatic-amino-acid transaminase (ArAT), 60 control genes for keto acid invertase, 123 control genes for alcohol/aldehyde dehydrogenase, and 27 control genes for acetyl esterase, which have the basis for the formation of strong flavor substances from amino acids.

Centimeter scale color printing with grayscale lithography

Structural color from artificial structures, due to its environmental friendliness and excellent durability, represents a route for color printing applications. Among various physical mechanisms, the Fabry–Perot (F–P) cavity effect provides a powerful way to generate vivid colors in either the reflection or transmission direction. Most of the previous F–P type color printing works rely on electron beam grayscale lithography, however, with this technique it is challenging to make large-area and low-cost devices. To circumvent this constraint, we propose to fabricate the F–P type color printing device by the laser grayscale lithography process. The F–P cavity consists of two thin silver films as mirrors and a photoresist film with a spatially variant thickness as the spacer layer. By controlling the laser exposure dose pixel by pixel, a centimeter-scale full-color printing device with a spatial resolution up to 5 μm × 5 μm is demonstrated. The proposed large area color printing device may have great potential in practical application areas such as color displays, hyperspectral imaging, advanced painting, and so on.

P‐5.12: One‐way Observable Window Signage with Vivid Colors Using Dye‐doped and Scattering Layers Which Enable to Make Images Invisible from Back Side

It stands to reason that someone observes mirrored imaging according to the direction of viewing if you draw something on the transparent material. The authors dislike this mirrored imaging problem, although it is not a fatal defect. In 2021, our research group proposed window signage using dye‐doped thin film layer to avoid this problem of mirrored imaging. But our 2021 model had a defect that color vividness was less than colors painted on non‐transparent materials because the images of our window signage are painted or printed on the transparent material for one‐way observable signage. To solve this weak point, we needed to find new technology for generating color using a transparent material. This paper shows a one‐way observable window signage using dye‐doped and special light scattering thin layers for unidirectional color generating by light controls, how to make colors more vivid and material development.

Tri-channel metasurface for watermarked structural-color nanoprinting and holographic imaging.

Structural-color nanoprinting, which can generate vivid colors with spatial resolution at subwavelength level, possesses potential market in optical anticounterfeiting and information encryption. Herein, we propose an ultracompact metasurface with a single-cell design strategy to establish three independent information channels for simultaneous watermarked structural-color nanoprinting and holographic imaging. Dual-channel spectrum manipulation and single-channel phase manipulation are combined together by elaborately introducing the orientation degeneracy into the design of variable dielectric nanobricks. Hence, a structural-color nanoprinting image covered with polarization-dependent watermarks and a holographic image can be respectively generated under different decoded environments. The proposed metasurface shows a flexible method for tri-channel image display with high information capacity, and exhibits dual-mode anticounterfeiting with double safeguards, i.e., polarization-controlled watermarks and a far-field holographic image. This study provides a feasible route to develop multifunctional metasurfaces for applications including optical anticounterfeiting, information encryption and security, information multiplexing, etc.

Three‐Dimensional Electrochromic Soft Photonic Crystals Based on MXene‐Integrated Blue Phase Liquid Crystals for Bioinspired Visible and Infrared Camouflage

Developing bioinspired camouflage materials that can adaptively change color in the visible and infrared (IR) regions is an intriguing but challenging task. Herein, we report an emerging strategy for fabricating dynamic visible and IR camouflage materials by the controlled in situ growth of novel photopolymerizable blue phase liquid crystals with cubic nanoarchitectures onto highly aligned MXene nanostructured thin films. The resulting MXene-integrated 3D soft photonic crystals exhibit vivid structural colors and reversible switching between a bright colored state and a dark black state under a low DC electric field. As an illustration, proof-of-concept pixelated devices that allow for pixel-controllable electrochromism are demonstrated. Furthermore, a free-standing electrochromic flexible film of such 3D soft photonic crystals is fabricated, where visible electrochromism and thermal camouflage are enabled by leveraging the superior electrothermal conversion and low mid-IR emissivity of MXene nanomaterials.

Three‐Dimensional Electrochromic Soft Photonic Crystals Based on MXene‐Integrated Blue Phase Liquid Crystals for Bioinspired Visible and Infrared Camouflage

AbstractDeveloping bioinspired camouflage materials that can adaptively change color in the visible and infrared (IR) regions is an intriguing but challenging task. Herein, we report an emerging strategy for fabricating dynamic visible and IR camouflage materials by the controlled in situ growth of novel photopolymerizable blue phase liquid crystals with cubic nanoarchitectures onto highly aligned MXene nanostructured thin films. The resulting MXene‐integrated 3D soft photonic crystals exhibit vivid structural colors and reversible switching between a bright colored state and a dark black state under a low DC electric field. As an illustration, proof‐of‐concept pixelated devices that allow for pixel‐controllable electrochromism are demonstrated. Furthermore, a free‐standing electrochromic flexible film of such 3D soft photonic crystals is fabricated, where visible electrochromism and thermal camouflage are enabled by leveraging the superior electrothermal conversion and low mid‐IR emissivity of MXene nanomaterials.

Ghosting-free multi-exposure image fusion for static and dynamic scenes

The visual system enables humans to perceive all details of the real-world with vivid colors, while high dynamic range (HDR) technology aims at capturing natural scenes in a closer way to human perception through a large dynamic range of color gamut. Especially for traditional –low dynamic range (LDR)– devices, HDR-like image generation is an attractive research topic. Blending a stack of input LDR exposures is called multi-exposure image fusion (MEF). MEF is indeed a very challenging problem and it is highly prone to halo effects or ghosting and motion blur in the cases when there are spatial discontinuities in between input exposures. To overcome these artifacts, MEF keeps the “best” quality regions of each exposure via a weight characterization scheme. This paper proposes an effective weight map extraction framework which relies on principal component analysis, adaptive well-exposedness and saliency maps. The characterized maps are later refined by a guided filter and a blended output image is obtained via pyramidal decomposition. Comprehensive experiments and comparisons demonstrate that the developed algorithm generates very strong statistical and visual results for both static and dynamic scenes. In addition, the designed method is successfully applied to the visible-infrared image fusion problem without any further optimization.

Come siamo diventati populisti: la lingua politica italiana della «terza Repubblica»

Vulgar, dishonest, incompetent: in recent years Italian politicians and their speeches have been described as such by journalists, linguists and political scientists. The turning point seems to date back to the three-year period from 2007 to 2009, when the political landscape in Italy appears to have taken on the most vivid colours of populism. These years saw the emergence of political movements and forces very different from each other, but which had some common characteristics: direct appeal to the people, intolerance for parliamentary representation rules, and a close relationship between supporters and a charismatic leader. In this paper the author wonders whether this representation of political communication reflects real new features or if it is rather the result of some longer processes in the history of Italian politics and its language. To answer this question, the author proposes a synthetic profile of political language in Italy over the last 10–15 years and focuses on its evolution and current trends, using written or transcribed texts and a corpus of parliamentary speeches from the last legislatures.

Cover

This piece depicts two women having starkly contrasting aging experiences. One has cognitive decline, able to interact physically with a world in vivid color as her mind turns black and white. The other woman has Parkinson's disease, which diminishes her motor ability, leaving her surroundings colorless and out of reach. With disease progression, the opposing sides come together. Their unique yet notably connected perspectives present profound lessons about aging. See the related article by Wong et al., pages 2731–2734.

Improved Floral Characteristics of Salvia coccinea through Intraspecific Hybridization

Salvia is the largest genus in the Lamiaceae with more than 1000 species. The species S. coccinea used in this study has naturalized in the southeastern United States and is an important plant for pollinators. This project aimed to improve phenotypic characteristics of S. coccinea for use in the landscape by selecting for increased petal size and unique petal color. Two elite accessions were selected for hybridization using the pedigree method. One selection displayed compact habit with bicolored coral and white flowers, while the other was slightly larger with solid red flowers. Selections were made based on improved flower color and larger petal size. The breeding program achieved a 25% increase in petal width and a more vivid petal color for the coral bicolored selections. Additionally, a 60% increase in petal width was achieved for red flowers. These novel selections are attractive plants for the landscape, displaying improved ornamental value and supporting local pollinator populations.

Obtaining brandy from the alcoholic fermented cashew tree, Goiano, Brazil

The process of obtaining the brandy consists of adding yeast to the must to transform the sugar into alcohol, the same microorganism as the fermentation agent. This work aimed to produce brandy from fermented cashew juice and perform physical-chemical analyses. The following analyses of alcohol at 20 °C, pH, total acidity, fixed and volatile were performed, as well as the color parameters in the CIEL system, (L*) luminosity (black/white); (a*) coloring in the red/green region and; (b*) coloring in the yellow/blue range; (c*) Chromaticity is the ratio of a*/b*; (h*) saturation and color angle and; (G*) brightness of the measured color. According to the literature, the results obtained were for alcohol 38.2ºGL and pH 4.53, with an alcoholic degree of 38 to 54% in volume at 20 °C, and its optimum pH for brandy, which is between pH 4.0 and 5.0 at higher levels. The total (38.99) and fixed (3.19) acidity found in this study corroborate the literature regarding volatile acidity, 97.37 mg/100ml of anhydrous alcohol expressed as acetic acid. The L* value (52.59) in the brandy sample presented lighter colors because it was closer to white, as well as the low values of a*(-1.18) and b*(2.47) values evaluated. Chromaticity presented 2.14; chroma defines color intensity, assuming values close to zero for neutral colors (gray) and around 60 for vivid colors. The values obtained for H* were high, whose value obtained 115.51, which characterizes the color of yellow, where hue-angle indicates the saturation of the object's color, is the angle formed between a* and b*. Therefore, they follow the literature and Brazilian legislation based on the results obtained.

Dual-channel anticounterfeiting color-nanoprinting with a single-size nanostructured metasurface.

Metasurface-based structural-colors are usually implemented by changing the dimensions of nanostructures to produce different spectral responses. Therefore, a single-size nanostructured metasurface usually cannot display structural-colors since it has only one design degree of freedom (DOF), i.e., the orientation angles of nanostructures. Here, we show structural-color nanoprinting images can be generated with a single-size nanostructured metasurface, enabled by designing the anisotropic nanostructure with different spectral responses along its long- and short-axis directions, respectively. More interestingly, the concept of orientation degeneracy of nanostructures can be applied in the metasurface design, which shows two spectral modulations can be implemented under different polarization directions of output light, thus extending the color-nanoprinting from single-channel to dual-channel. The proposed dual-channel metasurface used for anticounterfeiting color-nanoprinting has presented the advantages of ultra-compactness, high information capacity, and vivid colors, which can develop broad applications in fields such as high-end anticounterfeiting, high-density information storage, optical encryption, etc.

Investigation of highly luminescent inorganic perovskite nanocrystals synthesized using optimized ultrasonication method

All-inorganic halide perovskite nanocrystals are next-generation materials with excellent optical and semiconductor properties suitable for display applications. In this study, we introduce an optimized ultrasonication method for the high-capacity synthesis of highly luminescent inorganic perovskite nanocrystals. After the synthesis of CsPbBr3 with superior optical performance by ultrasonication method, halide anion exchange was performed to tune the stable emission wavelength over the entire visible range. In particular, the maximum photoluminescence wavelengths of the red and green perovskite nanocrystals were appropriate for light-emitting diode applications, and their full-width-at-half-maximum were very narrow, showing outstanding color purity. The materials also had excellent thermal and photo-stability, which is a necessary requirement for perovskite nanocrystal/organic light-emitting diode hybrid device applications. We formulated uniformly stable perovskite nanocrystal inks and optimized their physical and rheological properties for successful inkjet-printing. Finally, we fabricated a hybrid device with a color conversion layer based on the red and green perovskite nanocrystals synthesized using the optimized ultrasonication and halide-ion-exchange methods. The color reproduction range of the fabricated devices was 27.3 % wider than that of the National Television System Committee values, indicating very vivid colors.

Vivid structural colors of photonic crystals: Self-assembly of monodisperse silica nano-colloids synthesized using an anionic surfactant

Photonic crystals are widely applied in non-fading structural color production areas owing to their easy tunability. However, it is found that achieving high monodispersity in the case of particles diameter less than ∼100 nm is challenging. The understanding on the mechanism behind the synthesis could help to fabricate photonic crystals. Here we examine the effect of single anionic surfactant on the final particle diameter. Subsequently, the fabrication of photonic crystals using various size silica nanoparticles ranging from ∼250 nm to ∼50 nm by spin coating method is performed. Vivid structural colors from red to blue are obtained as a function of increasing particle size. This is rather peculiar since most studies shows opposite trend. Furthermore, the colloidal photonic crystals are prepared using spin coating method. The obtained spin coated photonic crystal films exhibit low viewing angle dependent structural colors.