Color Perception Research Articles

The human brain deals with violating general color or depth knowledge in different time courses

Utilizing the high temporal resolution of event-related potentials (ERPs), we compared the time course of processing incongruent color versus 3D-depth information. Participants were asked to judge whether the food color (color condition) or 3D structure (3D-depth condition) was congruent or incongruent with their previous knowledge and experience. The behavioral results showed that the reaction times in the congruent 3D-depth condition were slower than those in the congruent color condition. The reaction times in the incongruent 3D-depth condition were slower than those in the incongruent color condition. The ERP results showed that incongruent color stimuli induced a larger N270, larger P300, and smaller N400 components in the fronto-central region than the congruent color stimuli. Incongruent 3D-depth stimuli induced a smaller N1 in the occipital region, larger P300 and smaller N400 in the parietal-occipital region than congruent 3D-depth stimuli. The time–frequency analysis found that incongruent color stimuli induced a larger theta band (360–580 ms) activation in the fronto-central region than congruent color stimuli. Incongruent 3D-depth stimuli induced larger alpha and beta bands (240–350 ms) activation in the parietal region than congruent 3D-depth stimuli. Our results suggest that the human brain deals with violating general color or depth knowledge in different time courses. We speculate that the depth perception conflict was dominated by solving the problem with visual processing, whereas the color perception conflict was dominated by solving the problem with semantic violation.

Thermochromic materials in the paints and varnishes sector. Part I: perception and measurement of color

Thermochromic materials in the paints and varnishes sector. Part I: perception and measurement of color

Software and hardware complex based on the STM32F407VG microcontroller for the study of vibra-tions with the LIS3DSH accelerometer

Commonly used color models are reviewed and analyzed, namely the RGB model and subtractive models, including CMY and CMYK. The characteristics of colorimeters based on the use of RGB, CMY and CMYK models have been studied. A comparative analysis of the advantages and disadvantages of RGB and CMYK models was carried out. The developed digital colorimeter allows for express control of color characteristics with high metrological accuracy and does not require a high level of qualification of service personnel. This device reproduces the perception of color by human vision, and its use is intended for both people with normal and impaired vision. The great advantage of this device is its mobility, the speed of measurements and the absence of the need for a specialized laboratory and highly qualified specialists. Full-scale measurements of the output voltage on the photodiodes of the colorimeter corresponding to red, blue and green colors were carried out.

Bright blue-red emission and Optothermal behaviour of Sm(DBM)3Phen complex and amorphous silica nanoparticles

In the present article, we synthesise the Sm(DBM)3phen (SmDP), silica nanoparticles (SiNP) and Sm(DBM)3phen functionalized SiNPs (SiNP_SmDP), which were prepared using the modified Stober method. SEM images revealed an average Si NPs diameter of ∼324 nm. The absorption spectra of the samples showed broad absorption bands in the UV-blue region. Photoluminescence spectra revealed the broadband emission of SiNP centred at 435 nm; and sharp emission peaks corresponding to SmDP due to Sm3+ ion at 567 nm, 609 nm, and 650 nm ascribed due to the transitions 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, and 4G5/2 → 6H9/2, respectively. The SiNP_SmDP's emission spectra consist of amalgam emission with broadband due to SiNP; and sharps peaks due to SmDP complex. Under 405 nm laser excitation, the opto-thermal properties of SiNP_SmDP were explored in the range 293K–313K temperature. CIE coordinate analysis illustrates how colour perception varies with temperature. The maximum sensitivities values are 0.00816 K−1, 1.6326%K−1 and 0.00974 K−1, 3.43743%K−1 corresponding to the transitions 4G5/2 → 6H5/2: 4G5/2 → 6H7/2 and 4G5/2 → 6H5/2: 4G5/2 → 6H9/2 of Sm3+ ions.

Increasing magnitude of color differences amplifies category effects

Previous studies have identified differences in sensitivity characteristics between color discrimination and perception of suprathreshold color differences. However, it remains highly unclear how color difference sensitivity changes with increasing magnitudes of color difference along various color hues. This study aimed to quantify the sensitivity transition across various magnitudes of color differences and uncover the underlying mechanisms. Color discrimination sensitivities were measured using an adaptive staircase method for 32 isoluminant pedestal colors in the u'v' chromaticity diagram. For suprathreshold color differences, we employed the Maximum Likelihood Difference Scaling (MLDS) method to measure sensitivity to various color difference levels for the same 32 colors. Our findings confirmed the differences in sensitivity characteristics between discrimination and suprathreshold color difference perception. Furthermore, we observed increased sensitivities at many color category boundaries in suprathreshold color difference perception. By investigating the relation between the category effects and the color difference size levels through a model simulation, our findings suggest that the influence of color categories on the perception of color differences may become more pronounced as the magnitude of color differences increases.

WHAT COGNITIVE NEUROSCIENCE SAY ABOUT AESTHETIC EXPERIENCE?

Today, researchers can observe the neural responses to an aesthetic image in the human brain and examine the physiological reactions of viewers to an art object. Neuroaesthetics is a new field of study that characterizes the evolutionary history of the creation and evaluation of art by examining these responses. Neuroscientists, who have managed to map the neural pathways of the visual processing processes that occur in a person's brain while watching artworks, have been focusing on how the visual cortex processes information and reaches aesthetic judgment in recent years. The focus of this research is how a work of art is perceived, how the visual cortex processes information when reaching aesthetic judgments, color perception, synesthesia, and finally, the effects of brain damage on artists. In the study, firstly, the visual-spatial processes, which are the basic processes of visual perception, were discussed. In this way, object perception and the visual processes occurring in the brain during the perception of the art object were examined. In the next section, which draws attention to the perception of color as well as shape and spatial location, synesthesia, which has been the subject of many studies by neuroscientists in recent years and is known as the perception of one sense together with another sense, is discussed. Finally, studies on brain-damaged artists, one of the experimental methods most preferred by neuroscientists in research on aesthetic perception, and the data obtained from these studies are presented.

Exploring the Impact of Facade Color Elements on Visual Comfort in Old Residential Buildings in Shanghai: Insights from Eye-Tracking Technology

Building façade color plays a key role in shaping urban image, enhancing urban vitality, and optimizing citizens’ living experience. Moreover, colors can influence people’s perception of space, but the multiple interrelationships between color elements and users’ color evaluation and visual perception have not yet been thoroughly studied. In order to explore the relationships between color elements and visual perception and subjective comfort, this study discusses the matching relationship between color and the comfort of a residential building façade from three levels of color hue, lightness, and saturation by combining eye movement technology and a subjective evaluation. Taking Anshan San Village in Shanghai as the research object, the relationship model between color elements, visual perception, and subjective comfort is established through correlation analysis, linear regression, and multifactor regression analysis, and the correlation between single elements and multiple elements is explored from multi-dimensional perspectives. It aims to assess the operability of eye movement data as a measure of the visual comfort with the residential building façade color through multiple indicators and to explore and establish a new correlation assessment framework between the three attributes of façade color and users’ visual comfort. The results show that (1) highly saturated façade colors significantly increase cognitive load and decrease color evaluation. (2) Brightness has a non-linear relationship with visual perception and subjective evaluation, either too high or too low a brightness value will cause visual fatigue and thus reduce the color evaluation, and when the brightness is maintained at 40–80%, there will be a better color experience. (3) Warm tones such as red, orange, and yellow can strengthen the color perception to enhance the color evaluation of the façade; among cold tones, cyan and purple can also strengthen the visual perception of the color of the façade to enhance the color evaluation. After validation, the proposed new color comfort assessment method is feasible and comprehensive, and we hope it can provide a reference for the planning of old residential buildings and communities in the future.

The pathways of human color perception

The pathways of human color perception

Seeing is believing: The colour of silver alloys and the global silver circulation in the Chinese Ming and Qing dynasties

AbstractThis research investigates the correlation between colour perception and the circulation of silver in China during the Ming (1368–1644 CE) and Qing (1644–1911 CE) dynasties. The primary aim is to deepen our understanding of how silver alloys were perceived and experienced in this historical context while also situating our study within the broader context of the global silver trade. During the Ming and Qing dynasties, silver possessed immense historical significance as a precious commodity. We argue that copper had a more substantial influence on the final colour of silver alloys compared to lead. Furthermore, employing a colourimetric model, our Monte‐Carlo simulation demonstrates that over 70% of silver from Mesoamerica to China could be discerned by nonexperts using only their unaided vision, largely due to the elevated copper content. Crucially, our simulation experiment reveals differing effects of copper and lead on the colour of silver alloys. The latter demonstrates minimal change until reaching a threshold of 15%, signifying that lead is a suitable and cost‐effective substitute for silver. These findings suggest that the detection of silver purity was less demanding than previously assumed, opening up opportunities for arbitrage.

Public Perception of Scrub Color and Style in Plastic Surgery

Public Perception of Scrub Color and Style in Plastic Surgery

Effects of Changes in Lighting on Color Perception of 3D Objects

Effects of Changes in Lighting on Color Perception of 3D Objects

Facial expressions affect the memory of facial colors.

Facial color influences the perception of facial expressions, and emotional expressions bias how facial color is remembered. However, it remains unclear whether facial expressions affect daily facial color memory. The memory color effect demonstrates that knowledge about typical colors affects the perception of the actual color of given objects. To investigate the effect of facial color memory, we examined whether the memory color effect for faces varies depending on facial expression. We calculated the subjective achromatic point of the facial expression image stimulus and compared the degree to which it was shifted from the actual achromatic point between facial expression conditions. We hypothesized that if the memory of facial color is influenced by the facial expression color (e.g., anger is a warm color, fear is a cold color), then the subjective achromatic point would vary with facial expression. In Experiment 1, we recruited 13 participants who adjusted the color of facial expression stimuli (anger, neutral, and fear) and a banana stimulus to be achromatic. No significant differences in the subjective achromatic point between facial expressions were observed. Subsequently, we conducted Experiment 2 with 23 participants because Experiment 1 did not account for the sensitivity to color changes on the face; humans perceive greater color differences in faces than in non-faces. Participants selected which facial color they believed the expression stimulus appeared to be, choosing one of two options provided to them. The results indicated that the subjective achromatic points of anger and fear faces significantly shifted toward the opposite color direction compared with neutral faces in the brief presentation condition. This research suggests that the memory color of faces differs depending on facial expressions and supports the idea that the perception of emotional expressions can bias facial color memory.

A Plasmonic Optoelectronic Resistive Random-Access Memory for In-Sensor Color Image Cryptography.

The optoelectronic resistive random-access memory (RRAM) with the integrated function of perception, storage and intrinsic randomness displays promising applications in the hardware level in-sensor image cryptography. In this work, 2D hexagonal boron nitride based optoelectronic RRAM is fabricated with semitransparent noble metal (Ag or Au) as top electrodes, which can simultaneous capture color image and generate physically unclonable function (PUF) key for in-sensor color image cryptography. Surface plasmons of noble metals enable the strong light absorption to realize an efficient modulation of filament growth at nanoscale. Resistive switching curves show that the optical stimuli can impede the filament aggregation and promote the filament annihilation, which originates from photothermal effects and photogenerated hot electrons in localized surface plasmon resonance of noble metals. By selecting noble metals, the optoelectronic RRAM array can respond to distinct wavelengthsand mimic the biological dichromatic cone cells to perform the color perception. Due to the intrinsic and high-quality randomness, the optoelectronic RRAM can produce a PUF key in every exposure cycle, which can be applied in the reconfigurable cryptography. The findings demonstrate an effective strategy to build optoelectronic RRAM for in-sensor color image cryptography applications.

Colour Perception in Camper Van Interior Design Using Virtual Reality Technology

Virtual reality (VR) technology has been developing progressively and rapidly in the past decades. VR technology is used to create 3D models of rooms and spaces, which can be used to create more accurate and detailed designs. Colours used in interior design have the ability to create specific moods, create harmony, and change the perception of how large or small a space may look or feel. The purpose of this study is to explore the application of virtual reality technology in the interior design of a camper van considering the role of colour perception. We aim to determine the effect of colour on the interior design creating professional-looking 3D camper van layout. The results show that any non-professional in 3D design can design a functional and comfortable living space in the camper van using Vanspace 3D software. It was found that light colours and shades create the feeling of space, light, comfort and cosiness. When choosing colours for the interior design of a small limited space, as is the case with a camper van, it is advisable to combine warm earth colours, white and beige colours.

Exploring the differences between landscape colour and perceptive colour when walking through urban green space in summer

Landscape colour influences people’s visual behaviour and preferences. Insufficient exploration has been conducted on people’s colour perception when walking through urban green spaces (UGSs) dominated by green in summer. This study used eye-tracking technology to explore the differences between the visual attention colour (VAC) and space colour (SC), and the effect of spatial form on VAC. Participants were asked to view six walking spaces in two UGSs in Nanjing, China. The results indicated that SC and VAC had correlations in hue variance (yellow), saturation mean, and value variance, but weak correlations in hue mean (green), hue variance (green), and value mean. Additionally, the higher the spatial openness, the more reduction in brightness of the VAC compared to SC. The findings suggest that landscape visual perception studies need to consider the interaction between landscape colour, spatial form, and human top-down visual behaviour to support the design of UGSs.

N-Lüders channels: a novel class of rebit channels, their properties and applications

In a very recent paper, the complete classification of rebit channels has been achieved. Here, we exploit that result to show how the classification can be used to perform an exhaustive analysis of a novel class of rebit channels induced by effects called n-Lüders channels. In the final part of the paper we propose a concrete application of these channels within the mathematical framework of a quantum theory of color perception that originated the interest about a rebit channels classification.

Hue selectivity from recurrent circuitry in Drosophila

In the perception of color, wavelengths of light reflected off objects are transformed into the derived quantities of brightness, saturation and hue. Neurons responding selectively to hue have been reported in primate cortex, but it is unknown how their narrow tuning in color space is produced by upstream circuit mechanisms. We report the discovery of neurons in the Drosophila optic lobe with hue-selective properties, which enables circuit-level analysis of color processing. From our analysis of an electron microscopy volume of a whole Drosophila brain, we construct a connectomics-constrained circuit model that accounts for this hue selectivity. Our model predicts that recurrent connections in the circuit are critical for generating hue selectivity. Experiments using genetic manipulations to perturb recurrence in adult flies confirm this prediction. Our findings reveal a circuit basis for hue selectivity in color vision.

Tradescantia response to air and soil pollution, stamen hair cells dataset and ANN color classification.

Tradescantia plant is a complex system that is sensible to environmental factors such as water supply, pH, temperature, light, radiation, impurities, and nutrient availability. It can be used as a biomonitor for environmental changes; however, the bioassays are time-consuming and have a strong human interference factor that might change the result depending on who is performing the analysis. We have developed computer vision models to study color variations from Tradescantia clone 4430 plant stamen hair cells, which can be stressed due to air pollution and soil contamination. The study introduces a novel dataset, Trad-204, comprising single-cell images from Tradescantia clone 4430, captured during the Tradescantia stamen-hair mutation bioassay (Trad-SHM). The dataset contain images from two experiments, one focusing on air pollution by particulate matter and another based on soil contaminated by diesel oil. Both experiments were carried out in Curitiba, Brazil, between 2020 and 2023. The images represent single cells with different shapes, sizes, and colors, reflecting the plant's responses to environmental stressors. An automatic classification task was developed to distinguishing between blue and pink cells, and the study explores both a baseline model and three artificial neural network (ANN) architectures, namely, TinyVGG, VGG-16, and ResNet34. Tradescantia revealed sensibility to both air particulate matter concentration and diesel oil in soil. The results indicate that Residual Network architecture outperforms the other models in terms of accuracy on both training and testing sets. The dataset and findings contribute to the understanding of plant cell responses to environmental stress and provide valuable resources for further research in automated image analysis of plant cells. Discussion highlights the impact of turgor pressure on cell shape and the potential implications for plant physiology. The comparison between ANN architectures aligns with previous research, emphasizing the superior performance of ResNet models in image classification tasks. Artificial intelligence identification of pink cells improves the counting accuracy, thus avoiding human errors due to different color perceptions, fatigue, or inattention, in addition to facilitating and speeding up the analysis process. Overall, the study offers insights into plant cell dynamics and provides a foundation for future investigations like cells morphology change. This research corroborates that biomonitoring should be considered as an important tool for political actions, being a relevant issue in risk assessment and the development of new public policies relating to the environment.

THE FORMATION OF COLOR ASSOCIATIONS THROUGH STABLE UNITS FORMED WITH THE PARTICIPATION OF WORDS EXPRESSING COLOR

This research investigates the formation of color associations through stable units formed with the participation of words expressing color. Language plays a significant role in shaping our perception of colors, and the formation of stable units—linguistic constructs involving color words—provides a framework for understanding how these associations are established and maintained. Through a combination of linguistic analysis and experimental methods, this study explores how stable units influence color perception, categorization, and conceptualization. By uncovering the cognitive mechanisms underlying the formation of color associations through stable linguistic units, this research contributes to our understanding of the intricate interplay between language and cognition.

Effect of CTC processing on quality characteristics of green tea infusion: A comparative study with conventional orthodox processing

Traditionally, green tea is manufactured using orthodox processing methods. The CTC (curl, tear, and crush) method, widely employed in black tea processing, has minimal application in green tea production. However, it exhibits potential in terms of extraction efficiency to infusion. This study investigates the CTC method for producing green tea (CGT) and compares the extraction efficiency of bioactives to infusion with orthodox green tea (OGT). Total polyphenol, catechins, caffeine, and theanine extraction efficiencies were evaluated in both CGT infusion (CGTI) and OGT infusion (OGTI), along with water extract, antioxidant activity, color parameters, and sensory attributes. Results showed the amount of the bioactive compounds extracted from 2.00 g OGT could be attained from 0.75 to 1.00 g of CGT. This indicates that CGT is 100 to 167% more efficient in terms of the contents of bioactives in the infusion than OGT. This finding corroborates the observations of higher antioxidant activity of CGT compared to OGT. CGTI achieved similar taste and color perceptions with half the amount of OGT or even less. This enhanced extraction efficiency, along with CGTI's taste and color characteristics, can facilitate its commercial production, benefiting consumers and the tea industry. Industrial relevanceThis study provides comprehensive information on CTC green tea to the tea industry, which is the first of its kind with such in-depth details. As evident, the CTC processing mode of green tea promises more affordability to its growing consumers leading to increased demand for this type of tea which will immensely benefit the tea industry.