Complex Color Research Articles

The Impact of Task Difficulty, Environmental Color Complexity, and Teaching Models on AR-Assisted Subway Maintenance Training

This paper investigates whether different task difficulties, color complexity, and choice of instructional application mode affect cognitive load, usability, visual discomfort, and job performance in subway overhaul training tasks and compares the findings under AR learning modes with those under traditional paper-based learning manuals. This study had sixteen participants and used eight experimental conditions. Tests were completed for environmental color complexity, task difficulty, and instructional application mode. The experimental variables were analyzed using three-way analysis of variance. The results showed that the color complexity of the carriage environment did not affect the participants’ cognitive load and performance, but the use of AR glasses in subway maintenance was influenced by task difficulty and instructional application mode. For example, the AR image format reduced task completion time by an average of 25.9% for easy tasks, while the AR real-time format reduced head deflections by an average of 83.9%, suggesting that there is reliable potential for applying AR to subway overhaul training. This paper can provide a theoretical basis for developing training strategies for the different environments and tasks difficulties of subway maintenance.

PH- and Saccharide-Responsive Cyclometalated Iridium(III) Complexes with Boronic Acid Moieties Displaying a Wide Range of Phosphorescence Colors.

Single compounds displaying a wide range of luminescent colors are attractive optical materials for sensor applications. In this study, we present the beneficial combination of a cyclometalated iridium(III) complex scaffold and boronic acid units for designing stimulus-responsive luminescent materials with various emission colors. Five iridium(III) complexes bearing a diboronic acid ligand (bpyB2) were synthesized: Ir(C^N)bpyB2 (C^N=2-phenylpyridine (1), 2-(2,4-difluorophenyl)pyridine (2), 2-(4-methoxyphenyl)pyridine (3), benzo[h]quinoline (4), 1-phenylisoquinoline (5)). The luminescence color of Complexes 1-4 changed in response to the solution pH or saccharide concentration. Complex 1 exhibited a color change from orange to green-blue due to structural alteration of the boronic acid moiety from trigonal to tetrahedral. Furthermore, the luminescence color of Complex 1 changed reversibly due to repetitive changes in the solution pH between 5 and 10, enabling tuning of the luminescence color and pH tracking. Furthermore, the color range was tuned by selecting an appropriate C^N ligand. Time-dependent density functional theory investigations revealed that the dramatic and reversible color changes could be ascribed to a switch in the electronic distribution in the lowest excited state from bpyB2 to C^N. The stimulus-responsive iridium(III) complexes provide a prospective scaffold for future applications in color-tunable optical devices and chemosensing systems.

Fine-grained restoration of Mongolian patterns based on a multi-stage deep learning network

Mongolian patterns are easily damaged by various factors in the process of inheritance and preservation, and the traditional manual restoration methods are time-consuming, laborious, and costly. With the development of deep learning technology and the rapid growth of the image restoration field, the existing image restoration methods are mostly aimed at natural scene images. They do not apply to Mongolian patterns with complex line texture structures and high saturation-rich colors. In order to solve this problem, this paper proposes a Mongolian pattern restoration model with a multi-stage network. In the first stage, a pyramid context encoder network is introduced to learn the contextual features of the image for global restoration; in the second stage, a local restoration network is constructed by combining the RIC convolutional layer and the MPD down-sampling module; and in the third stage, the global refinement restoration is carried out by using the U-Net network that incorporates the attention mechanism. The experimental results show that this paper’s method achieves remarkable results in the Mongolian pattern repair task, using four evaluation metrics such as Peak Signal-to-Noise Ratio (PSNR), Structural Similarity (SSIM), LPIPS, and L1 Loss to compare with the existing method. The results show that this paper’s method performs well in the Mongolian pattern repair task. Also, the performance of the model on public datasets verifies its wide applicability. The method in this paper provides an efficient solution for the digital restoration of Mongolian motifs and has important application prospects.

Urban Architectural Color Evaluation: A Cognitive Framework Combining Machine Learning and Human Perception

Architectural color significantly impacts the quality of built environments and is closely related to the physical and mental health of residents. Previous studies have conducted numerous valuable explorations in this field; however, the challenge of quantitatively measuring the characteristics of architectural colors in depth and examining the complex relationship between these colors and human perception remains an unresolved issue. To this end, this study builds upon recent advancements in data technology and emotion analysis to develop a comprehensive cognitive framework for urban architectural color evaluation. It combines machine learning techniques and perception scales, utilizing both objective and subjective data. By acquiring and recognizing numerous street-view images of the Changsha Central District, we quantitatively examined the hue, saturation, value, color complexity index and color harmony index of urban architectural colors and investigated the complex relationships between human perception and architectural colors through large-scale participant ratings and correlation analyses. The results show that the architectural colors of the study area are warm, with low saturation and moderate value. Most areas exhibit a high color complexity index, whereas the overall color harmony score is low. Human-perception evaluations indicate that people are generally satisfied with the urban architectural colors of the Changsha Central District. For further optimization, the saturation and color harmony scores need to be enhanced. This study provides a comprehensive evaluation of urban architectural color quality, visualizing the complex relationship between urban architectural color and human perception. It offers new perspectives for improving the built environments and supporting sustainable development, with practical application value.

Spectrophotometric determination of Meloxicam in Pure Form and its Pharmaceutical Formulation following azo dye formation with 4-nitroaniline

A fast, cheap, and straightforward spectrophotometric method has been proposed to determine meloxicam (MEL) in its pure form and pharmaceutical formulation. The technique involves diazotizing the (NH2) group in 4-nitroaniline with NaNO2 followed by a reaction with meloxicam to produce a stable and colored complex in a basic medium. This complex demonstrates maximum absorbance at 514 nm. The developed method's linearity ranges from 2.0 - 25 μg mL-1, and the molar absorptivity is 1.5989×104 L mol-1 cm-1. The RSD% is lower than 1.55%. Additionally, the limit of detection (LOD) is 0.2019 μg mL-1. The method successfully determines the pharmaceutical preparation containing meloxicam (Loxim tablets) with a recovery rate of no less than 97.9%.

Design of cascaded diffractive optical elements generating different intensity distributions at several operating wavelengths

We consider the design of cascaded diffractive optical elements (DOEs) for generating specified intensity distributions for several incident beams with different wavelengths. For each incident beam with a given wavelength, the cascaded DOE forms a different specified intensity distribution. The problem of DOE design is formulated as the problem of minimizing a functional that depends on the functions of diffractive microrelief height of the cascaded DOE and represents the deviations of the intensity distributions generated at the operating wavelengths from the specified ones. Explicit expressions are obtained for the derivatives of the functional, and on this basis, a gradient method for calculating a cascaded DOE is formulated. The proposed gradient method is used for the calculation of cascaded DOEs focusing radiation of three different wavelengths into different areas. In particular, the calculation of a cascaded DOE generating a complex color image of parrots is considered. The presented numerical simulation results demonstrate high performance of the proposed method.

Research on the Construction and Application of a SVM-Based Quantification Model for Streetscape Visual Complexity

Visual complexity is a crucial criterion for evaluating the quality of urban environments and a key dimension in arousal theory and visual preference theory. Objectively quantifying visual complexity holds significant importance for decision-making support in urban planning. This study proposes a visual complexity quantification model based on a support vector machine (SVM), incorporating six key indicators, to establish a mapping relationship between objective image features and subjective complexity perception. This model can efficiently and scientifically predict street view complexity on a large scale. The research findings include the following: (1) the introduction of a new quantification dimension for the urban environment complexity—hierarchical complexity– which reflects the richness of street elements based on an in-depth semantic understanding of images; (2) the established complexity quantification model demonstrates high accuracy, with the indicators ranked by contribution for compression ratio, grayscale contrast, hierarchical complexity, fractal dimension, color complexity, and symmetry; and (3) the model was applied to predict and analyze the visual complexity of the Xiaobailou and Wudadao Districts in Tianjin, revealing that the visual complexity of most streets is moderate, and targeted recommendations were proposed based on different levels of visual complexity.

Вплив червоного та синього електромагнітного випромінювання на каталазну активність зародків в’юна Misgurnus fossilis L.

Photobiomodulation therapy is widely used to treat various pathological conditions. This therapy is based on the use of monochromatic light radiation. The light of the visible spectrum induces different biological effects at the molecular and cellular levels, both therapeutic and toxic. The obtained effect depends on the length of radiation, exposure, etc. One of the possible mechanisms of such influence is the regulation of pro-oxidant-antioxidant homeostasis. In order to clarify the mechanism of action of electromagnetic radiation (EMR) of different spectral composition, catalase (CAT) activity was investigated in germ cells of loach Misgurnus fossilis L. during embryogenesis. Since, loach embryos are an adequate system that reflects the physiological state of the cell both under normal conditions and as a result of the influence of various pharmacological, physical and chemical agents. The resulting zygotes were irradiated (10 min) with blue and red LEDs (λ = 460 and 660 nm, respectively). The activity of CAT was determined by the ability of hydrogen peroxi­de to form a stable colored complex with molybdenum salts. It was established that EMR of the red spectrum has the most pronounced biological effects and caused significant changes in catalase activity during embryogenesis relative to control and blue light. The maximum increase of the indicator occurs at the stage of 16 blastomeres, and at the stage of 8 and 10 divisions, a gradual decrease in enzymatic activity is observed. Irradiation by the light of the blue spectrum lasting 10 min did not cause significant changes in catalase activi­ty relative to the control at the early stages of loach embryogenesis. The obtained results suggest that CAT, one of the key enzymes of the antioxidant defense system, undergoes photoactivation under the influence of red light.

Formation mechanism of iron-catechol complexes in the colored periostracum of Corbicula spp.

The shell color of Corbicula clams, which are globally distributed, is roughly divided into yellowish and blackish depending on the environmental conditions of the sediment. The formation of an iron-L-3,4-dihydroxyphenylalanine (DOPA) complex in a thin organic layer, called the periostracum, on a calcareous layer causes the blackening of the clamshell. However, the iron-DOPA complex formation mechanism is unclear. To reveal how the iron is transported from the aquatic environment to the periostracum, cross-sectional analyses of the shell were conducted using an electron probe microanalyzer and Raman spectroscopy to investigate the distribution and structure of iron in the shell. Iron was only present in the periostracum, excluding deposition, and all iron was in the form of an iron-DOPA complex. Attenuated total reflection infrared spectroscopy and oxygen K-edge X-ray absorption fine structure spectroscopy revealed that the molecular structure of the native periostracum is independent of shell color. These results indicate that dissolved iron-organic complexes diffuse from the aqueous environment to the periostracum, forming iron-DOPA complex through ligand exchange. Because the iron-DOPA complex color depends on the pH, the shell color can serve as a historical indicator of the shell's growth environment.

Mangrove Extraction Algorithm Based on Orthogonal Matching Filter-Weighted Least Squares.

High-precision extraction of mangrove areas is a crucial prerequisite for estimating mangrove area as well as for regional planning and ecological protection. However, mangroves typically grow in coastal and near-shore areas with complex water colors, where traditional mangrove extraction algorithms face challenges such as unclear region segmentation and insufficient accuracy. To address this issue, in this paper we propose a new algorithm for mangrove identification and extraction based on Orthogonal Matching Filter-Weighted Least Squares (OMF-WLS) target spectral information. This method first selects GF-6 remote sensing images with less cloud cover, then enhances mangrove feature information through preprocessing and band extension, combining whitened orthogonal subspace projection with the whitened matching filter algorithm. Notably, this paper innovatively introduces Weighted Least Squares (WLS) filtering technology. WLS filtering precisely processes high-frequency noise and edge details in images using an adaptive weighting matrix, significantly improving the edge clarity and overall quality of mangrove images. This innovative approach overcomes the bottleneck of traditional methods in effectively extracting edge information against complex water color backgrounds. Finally, Otsu's method is used for adaptive threshold segmentation of GF-6 remote sensing images to achieve target extraction of mangrove areas. Our experimental results show that OMF-WLS improves extraction accuracy compared to traditional methods, with overall precision increasing from 0.95702 to 0.99366 and the Kappa coefficient rising from 0.88436 to 0.98233. In addition, our proposed method provides significant improvements in other metrics, demonstrating better overall performance. These findings can provide more reliable technical support for the monitoring and protection of mangrove resources.

Palette‐Based Recolouring of Gradient Meshes

AbstractGradient meshes are a vector graphics primitive formed by a regular grid of bicubic quad patches. They allow for the creation of complex geometries and colour gradients, with recent extensions supporting features such as local refinement and sharp colour transitions. While many methods exist for recolouring raster images, often achieved by modifying an automatically detected palette of the image, gradient meshes have not received the same amount of attention when it comes to global colour editing. We present a novel method that allows for real‐time palette‐based recolouring of gradient meshes, including gradient meshes constructed using local refinement and containing sharp colour transitions. We demonstrate the utility of our method on synthetic illustrative examples as well as on complex gradient meshes.

Spectrophotometric Determination of Curcumin using 3-Methyl-2-benzothiazolinone Hydrazone Hydrochloride Hydrate as Electrophilic Coupling Agent

Introduction: Nutraceuticals are products derived from food sources that provide extra health benefits in addition to the basic nutritional value found in foods. Spectrophotometric methods for the determination of curcumin were developed, which are simple, sensitive, selective, rapid, and reliable. Methods: The methods are based on the reduction of iron (III) to iron (II) by 3-Methyl-2- benzothiazolinone hydrazone hydrochloride hydrate (MBTH), which is an electrophilic coupling agent and subsequent reaction with curcumin in mild hydrochloric acid medium. Spectrophotometric methods for the determination of curcumin were developed, which are simple, sensitive, selective, rapid, and reliable. The methods are based on the reduction of iron (III) to iron (II) by 3-Methyl-2-benzothiazolinone hydrazone hydrochloride hydrate (MBTH), which is an electrophilic coupling agent and subsequent reaction with curcumin in mild hydrochloric acid medium. Result: The reaction produces a bluish–green complex with maximum absorbance at 670 nm. The colour complex can be extracted into chloroform. The methods obey Beer’s law in the range 0.3-7.0 and 0.2-7.0 (μg mL-1). Conclusion: 10 common anions and cations were added, and the method was tested, and no interference was observed. The proposed methods offered the advantages of having good reproducibility and were satisfactorily worked out to estimate the amount of curcumin in various turmeric samples.

Study of complexation behavior for Cobalt(II) with a new ligand derived from pA benzoic acid to estimate Co2+content in vitB12

The spectrophotometric method was suggested for the determination of trace amounts of cobalt. The method is based on the reaction of cobalt (selected between some ions) with a novel prepared reagent 4-((1-ethoxy-1,3-dioxobutan-2-yl) diazenyl)benzoic acid at pH 9 in the presence of sodium hydroxide as a basic medium to form a distinct color complex that shows maximum absorption at λmax = 421nm. Under specific conditions, Beer’s law is obeyed to control the concentration mode of 10-60 ppm. The molar absorptivity was 106.0695 L.mol-1cm-1, Sandellʹs sensitivity was 2.6×10-5, and the detection coefficient was 0.9984. The method was applied with good results to estimate cobalt in multiple doses of vitamin B12 (tablets and injection), then compared with FAAS instrumental, for which the results were close.

Colored Complexes of Bidentate Lewis Acids R[OB(C6F5)2]2 (R = 1,4-C6H4, 1,4-C6F4) with Pyrazine

Colored Complexes of Bidentate Lewis Acids R[OB(C6F5)2]2 (R = 1,4-C6H4, 1,4-C6F4) with Pyrazine

A Reaction-Based Approach to Colorimetric Detection of Organic Analytes in Water Using a Chlorine-Containing Carbocyanine Dye and Hypochlorite

Water quality control employs techniques mostly targeting individual analytes; group detection is also practiced, but the choice of group methods is limited, which supports interest in developing such methods. We have examined the interaction of hypochlorite with a chlorine-containing heptamethine carbocyanine dye in the presence of 30 organic and inorganic model analytes that were found to induce diverse color changes in the system. The main supposed mechanisms are retardation of the dye oxidation with hypochlorite (presumably by scavenging chlorine radicals) and substitution of chlorine atom in the dye by the most nucleophilic analytes (amines, amino acids, proteins, DNA, phenol). The grass-green substitution product is more contrastingly visible against the dark-purple hypochlorite oxidation product of the dye than against the original emerald-green dye. The indicator reaction is monitored photographically for 10–40 min and the images are processed using principal component analysis (PCA) or linear discriminant analysis (LDA), allowing for data convolution for the complex color transitions. Nitrogen compounds are discriminated from the others, and more reactive analytes (tryptophan, cysteine, bovine serum albumin, and DNA) are detected in the presence of less reactive ones in natural water. The system is promising for the development of group assays for dissolved organic matter and the discrimination of water samples.

Tetrafunctionalized Azocalix[4]resorcinarene Dye: A Chromogenic Supramolecule Used for the Selective Liquid-Liquid Extraction and Spectrophotometric Determination of Cu(II)

Background: The detection and extraction of trace metal ions, particularly copper(II), are critical for environmental monitoring and industrial processes. Calixresorcinarene, with its unique cavity structure, offers excellent platforms for designing selective chemosensors and extractants. Functionalization of calixresorcinarene with azo groups can enhance their chromogenic properties, enabling both extraction and detection in a single step. Objective: This study aimed to evaluate its (Azocalix[4]resorcinaren) efficacy as a selective chemosensor for the liquid-liquid extraction and spectrophotometric determination of Cu(II) ions. Methods: Application in Extraction and Detection: The ability of the dye to selectively extract Cu(II) ions from aqueous solutions was investigated via liquid-liquid extraction experiments. The dye-Cu(II) complex formation was monitored by UV-Vis spectrophotometry, with systematic optimization of experimental conditions, including pH, solvent system, and extraction duration. Results: The synthesized azocalix[4]resorcinarene dye exhibited a pronounced selectivity towards Cu(II) ions, forming a stable, colored complex. The complexation induced a distinct bathochromic shift in the absorption spectrum, allowing for precise spectrophotometric detection. Optimal extraction was achieved at a specific pH and solvent combination, with the method demonstrating a low detection limit and high sensitivity. The dye showed minimal interference from other metal ions, confirming its selectivity for Cu(II). Conclusion: The tetrafunctionalized azocalix[4]resorcinarene dye is a highly effective chromogenic agent for the selective extraction and detection of Cu(II) ions. Its robust performance in both extraction efficiency and spectrophotometric detection underscores its potential utility in environmental analysis and industrial applications where trace metal detection is crucial.

Reallocation of the magnificent catshark Proscyllium magnificum Last & Vongpanich, 2004 to the genus Ctenacis Compagno, 1973 (Carcharhiniformes: Proscylliidae).

The magnificent catshark Proscyllium magnificum was described in 2004 based off five specimens collected in the Andaman Sea off Myanmar. It was originally allocated to the genus Proscyllium, but recent molecular analyses suggested it was more closely related to the harlequin catshark Ctenacis fehlmanni from the western Indian Ocean. This study incorporated meristics and external and internal morphology, together with molecular data to reclassify the magnificent catshark as Ctenacis magnificum and provides revised diagnoses for the genera Ctenacis and Proscyllium. Ctenacis consists of two allopatric Indian Ocean species, while Proscyllium is monotypic genus confined to the northwest Pacific. The revised Ctenacis can be distinguished from Proscyllium in having a broader and longer head (head length 21%-23% vs. 16%-18% of total length), distance between pectoral and pelvic bases shorter than head length (vs. greater than head length), more teeth (upper jaw with 80-86 vs. 46-62 tooth files), and a complex colour pattern of dark reddish-brown blotches and saddles (vs. colour pattern of small black spots). A revised key to the genera of proscylliids and species of Ctenacis is provided.

Urban Color Perception and Sentiment Analysis Based on Deep Learning and Street View Big Data

The acceleration of urbanization has resulted in a heightened awareness of the impacts of urban environments on residents’ emotional states. This present study focuses on the Lixia District of Jinan City. By using urban street view big data and deep learning methods, we undertook a detailed analysis of the impacts of urban color features on residents’ emotional perceptions. In particular, a substantial corpus of street scene image data was extracted and processed. This was performed using a deep convolutional neural network (DCNN) and semantic segmentation technology (PSPNet), which enabled the simulation and prediction of the subjective perception of the urban environment by humans. Furthermore, the color complexity and coordination in the street scene were quantified and combined with residents’ emotional feedback to carry out a multi-dimensional analysis. The findings revealed that color complexity and coordination were significant elements influencing residents’ emotional perceptions. A high color complexity is visually appealing, but can lead to fatigue, discomfort, and boredom; a moderate complexity stimulates vitality and pleasure; high levels of regional harmony and aesthetics can increase perceptions of beauty and security; and low levels of coordination can increase feelings of depression. The environmental characteristics of different areas and differences in the daily activities of residents resulted in regional differences regarding the impacts of color features on emotional perception. This study corroborates the assertion that environmental color coordination has the capacity to enhance residents’ emotions, thereby providing an important reference point for urban planning. Planning should be based on the functional characteristics of the region, and color complexity and coordination should be reasonably regulated to optimize the emotional experiences of residents. Differentiated color management enhances urban aesthetics, livability, and residents’ happiness and promotes sustainable development. In the future, the influences of color and environmental factors on emotions can be explored in depth, with a view to assist in the formulation of fine urban design.

Superwettable microchip for visual detection of date-rape drug in beverages

Gamma-hydroxybutyric acid (GHB), which is used in drug-facilitated sexual assault, is typically delivered in the form of gamma-butyrolactone (GBL) in beverage carriers. In response to the growing need of methods for rapid and on-site sensing of the drugs, we carried out an investigation aimed at developing a superwettable microchip for visual detection of the date-rape drug GBL in adulterated beverages. The superwettable microchip is comprised of Fe3O4 nanoparticles which aggregate to form a reactive spot on a superhydrophobic fabric. The spot captures and confines microdroplets containing GBL on the superhydrophobic substrate. Fe(III), generated by HCl promoted reaction of the Fe3O4 spot, then participates in a colorimetric reaction with GBL to form a naked eye observable colored complex. Quantitative determination of GBL in beverages is achieved by analyzing the red proportion of a smartphone camera derived image. The detection range of this assay protocol is ca. 0.1–10 mg mL−1, which meets the requirements to detect potentially dangerous concentration of GBL in drinks. The detection stability of the superwettable microchip for GBL in water and common beverages is maintained over at least 30 cycles.

A pH-responsive dual-emission composite for fast detection of BAs and visual monitoring seafood freshness with large luminescence color difference

Sensing biogenic amine (BAs) content is very important for assessing food freshness. To address the limitations such as small color difference values (ΔE) and complex preparation of probes for visualizing the freshness of seafood, a pH-responsive ratiometric fluorescent probe (EnEB) was prepared by Eu(NO3)3, trimeric acid (BTC), and hydrochloric acid norepinephrine (Enr). EnEB emitted blue (446 nm) and red fluorescence (616 nm) originating from Enr and Eu3+, respectively, and exhibiting a fluorescence wavelength difference up to 170 nm. The ratiometric fluorescent signals of EnEB showed a linear correlation with pH in the range of 5.5–8.0. Thus, EnEB can rapidly and precisely detect BAs, such as histamine, tyramine, and spermine, with detection limits and response times of 1.14 μmol/L (3 s), 1.04 μmol/L (8 s), and 0.41 μmol/L (2 s), respectively. Furthermore, an EnEB aerogel was prepared by loading EnEB in a matrix formed by polyvinyl alcohol (PVA) and agarose (AG). EnEB aerogel exhibited excellent acid-base gas-sensing properties. The fluorescence color of EnEB aerogel can change significantly with the deterioration of seafood. When seafood changed from fresh to decayed, the ΔE value of EnEB aerogel was as high as 80.9. Importantly, the results of seafood freshness by naked eye using EnEB aerogel was consistent well with the TVB-N content and the freshness standard stipulated by national food standard, indicating EnEB aerogel can accurately visually and real-time monitor seafood freshness. Furthermore, the strategy for sensing food freshness based on EnEB aerogel also offered multiple color variations to indicate fine freshness levels of seafood. This work provided a convenient, efficient, and accurate approach to assessing the freshness of seafood. Additionally, EnEB also has promising applications in security and anti-counterfeiting.