scholarly journals ГЕНЕЗИС ТА ОСОБЛИВОСТІ ФОРМУВАННЯ БАЗОВИХ МОДЕЛЕЙ ІДЕНТИФІКАЦІЇ КОЛЬОРУ

2019 ◽  
pp. 113-124
Author(s):  
О. М. Яремчук ◽  
А. В. Кулік
Keyword(s):  
Initial Period ◽  
Color Space ◽  
Color Perception ◽  
Mathematical Representation ◽  
Light Sources ◽  
Technical Literature ◽  
Visualization System ◽  
Color Spectrum ◽  
Color Circle ◽  
Phenomenological Perception

Purpose. The determination of the formation features of basic models of color and identification of color in the initial stages (the 18th – 19th centuries) of scientific research of the problem. Methodology of the research is based on historical and cultural method. The source base is the artistic, scientific and technical literature of the studied period and also artefacts. Results. This publication reveals a generalized approach to theoretical developments on color perception and identification, and covers the initial period of color research and the formation of basic models of color (the 18th – 19th centuries). So in the middle of the 17th century I. Newton founded a seven-color ordering model, placing them to a closed color circle. At about the same time, other attempts at color systemization were proposed, such as color identification in the form of tables of existing paints, the work of I. Brennen and R. Waller. Subsequently, Jacob Christoph Le Blon concluded that in order to get results, you could use only three colors, namely red, yellow and blue. Based on this work, M. Harris presented his color circle, J. Lambert – a triangular color pyramid, and Ph.Runge built a color sphere using the principle of the globe. Goethe, contrary to Newton's physical doctrine of colors, conceived another system, it was based on the phenomenological perception of color. According to Goethe and his followers, the colors come from the struggle of "light" and "darkness". A. Schopenhauer took the step that J. Goethe lacked in his thinking: A. Schopenhauer formed a doctrine of color in terms of psychology, noting the enormous role that our brain plays in color perception, and proposing his model of identification by the principle of intensity / extensiveness/quality. for the formal description of the tri-color system of color, forming a mathe-confirmation of T. Young's theory and came to the conclusion that for the comparison of all shades, three light sources were needed and sufficient: in the red, green and blue parts of the spectrum. The perception of other colors is conditioned by the interaction of these constituents. In his work, J. Maxwell proved that all colors come from a mixture of three spectral colors: red, green, and blue. Based on his research, he introduced the first two-dimensional color spectrum visualization system. H. Grassmann's merit is the mathematical representation of the three spectral colors. E. Hering's theory highlights the psychological aspects of color vision: warm sensations occur for white, yellow, and red colors, while cold sensations occur for black, dark blue, and light blue. G. Peano introduced the concept of "color space" as a system of vector space equations.

scholarly journals What we talk about when we talk about color

2020 ◽  
Author(s):  
Colin R. Twomey ◽  
Gareth Roberts ◽  
David Brainard ◽  
Joshua B. Plotkin
Keyword(s):  
Visible Light ◽  
Color Space ◽  
Color Perception ◽  
Geographic Location ◽  
Cross Cultural ◽  
Cultural Variation ◽  
Inference Algorithm ◽  
Color Categories ◽  
New Directions ◽  
Different Color

Names for colors vary widely across languages, but color categories are remarkably consistent [1–5]. Shared mechanisms of color perception help explain consistent partitions of visible light into discrete color vocabularies [6–10]. But the mappings from colors to words are not identical across languages, which may reflect communicative needs – how often speakers must refer to objects of different color [11]. Here we quantify the communicative needs of colors in 130 different languages, using a novel inference algorithm. Some regions of color space exhibit 30-fold greater demand for communication than other regions. The regions of greatest demand correlate with the colors of salient objects, including ripe fruits in primate diets. Using the mathematics of compression we predict and empirically test how languages map colors to words, accounting for communicative needs. We also document extensive cultural variation in communicative demands on different regions of color space, which is partly explained by differences in geographic location and local biogeography. This account reconciles opposing theories for universal patterns in color vocabularies, while opening new directions to study cross-cultural variation in the need to communicate different colors.

scholarly journals Impact of different standard lighting sources on red jadeite and color quality grading

2019 ◽  
Vol 23 (4) ◽  
pp. 371-378
Author(s):  
Xin Pan ◽  
Ying Guo ◽  
Ziyuan Liu ◽  
Zikai Zhang ◽  
Yuxiang Shi
Keyword(s):  
Light Source ◽  
Color Space ◽  
Sample Surface ◽  
Color Temperature ◽  
Integrating Sphere ◽  
Light Sources ◽  
Light Spectrum ◽  
Fisher Discriminant Analysis ◽  
Fisher Discriminant ◽  
Quality Grading

The purpose of this paper is to investigate the standard light source for grading and displaying the color of red jadeite and to classify the color. With Raman spectrometer, ultraviolet-visible spectrophotometer and X-ray fluorescence spectrometer, the results show that, the Fe 3+ is the main chromogenic mineral of red jadeite, which negatively correlates with the tonal angle, while the color of red jadeite has a positive correlation with the hematite content. The color of 120 red jadeite samples was examined by collecting the reflective signaled from the sample surface using an integrating sphere with the portable X-Rite SP62 spectrophotometer based on CIE 1976 L*a*b* uniform color space. The color parameters of jadeite samples under D65, A and CWF standard light sources were analyzed. The light spectrum of D65 light source is continuous, relatively smoothed with high color temperature, which makes the sample color close to that under the natural light and can be used as the best evaluation light source. A light source contributes to improve the red tone of jadeite, which is the best light source for commercial display of red jadeite. CWF light source can be used as the auxiliary lighting for color evaluation. The color of red jadeite is divided into five levels from best to worst using K-Means cluster analysis and Fisher discriminant analysis under D65 light source: Fancy Vivid, Fancy Deep, Fancy Intense, Fancy dark and Fancy.

scholarly journals Color signals through dorsal and ventral visual pathways

2013 ◽  
Vol 31 (2) ◽  
pp. 197-209 ◽  
Author(s):  
BEVIL R. CONWAY
Keyword(s):  
Visual Processing ◽  
Color Space ◽  
Temporal Cortex ◽  
Color Perception ◽  
Original Data ◽  
Brain Regions ◽  
Neural Representation ◽  
Inferior Temporal Cortex ◽  
Extrastriate Cortex ◽  
Chromatic Contrast

AbstractExplanations for color phenomena are often sought in the retina, lateral geniculate nucleus, and V1, yet it is becoming increasingly clear that a complete account will take us further along the visual-processing pathway. Working out which areas are involved is not trivial. Responses to S-cone activation are often assumed to indicate that an area or neuron is involved in color perception. However, work tracing S-cone signals into extrastriate cortex has challenged this assumption: S-cone responses have been found in brain regions, such as the middle temporal (MT) motion area, not thought to play a major role in color perception. Here, we review the processing of S-cone signals across cortex and present original data on S-cone responses measured with fMRI in alert macaque, focusing on one area in which S-cone signals seem likely to contribute to color (V4/posterior inferior temporal cortex) and on one area in which S signals are unlikely to play a role in color (MT). We advance a hypothesis that the S-cone signals in color-computing areas are required to achieve a balanced neural representation of perceptual color space, whereas those in noncolor-areas provide a cue to illumination (not luminance) and confer sensitivity to the chromatic contrast generated by natural daylight (shadows, illuminated by ambient sky, surrounded by direct sunlight). This sensitivity would facilitate the extraction of shape-from-shadow signals to benefit global scene analysis and motion perception.

Contribution of Green Jadeite-Jade’s Chroma Difference Based on CIE 1976 L*a*b* Uniform Color Space

2010 ◽  
Vol 177 ◽  
pp. 620-623 ◽  
Author(s):  
Ying Guo ◽  
Jun Zhang ◽  
Tao Mo
Keyword(s):  
Color Space ◽  
Color Perception ◽  
Correlation Coefficients ◽  
Color Difference ◽  
Green Color ◽  
Difference Formula ◽  
Positive Linear Correlation ◽  
Cie Lab ◽  
Human Eyes ◽  
The Impact

The correlations between lightness and chroma, lightness difference and color difference, chroma difference and color difference were studied to evaluate the impact of lightness on color. Based on color difference formula CIE LAB in the uniform color space CIE L*a*b* it is learnt that H*ab of jadeite jade green colors has made little contribution to E*ab. Given the fact that human eyes are relatively sensitive to the color perception of lightness difference and that lightness and chroma affect each other, lightness of jadeites has been divided into two groups: while the lightness of green is relatively low (L*  19.52), lightness and chroma have positive linear correlation (correlation coefficient L*  C* = 0.971), which means the higher lightness the higher chroma and brings brighter green color; while L* > 19.52 , there is no one-to-one correspondence between lightness and chroma, and the highest chroma 77.64 can be reached when L* = 37.63. The high partial correlation coefficients L*ab  E*ab = 0.974 and C*ab  E*ab = 0.971 reveal that both L*ab and C*ab are not affected by the lightness of jadeite and are equally important to E*ab. It is concluded that the quality estimation of green color of Jadeite Jade should be primarily based on lightness which is the most intuitive factor and consistent with the color perception, and then followed by the evaluation of chroma and hue.

scholarly journals Biochemical and Gene Expression Involved in Red Blush Color Development in ‘Ambrosia’ Apple

2019 ◽  
Vol 144 (3) ◽  
pp. 164-171
Author(s):  
Peter M.A. Toivonen ◽  
Jared Stoochnoff ◽  
Kevin Usher ◽  
Changwen Lu ◽  
Paul A. Wiersma ◽  
...  
Keyword(s):  
Gene Expression ◽  
Color Space ◽  
Skin Surface ◽  
Ultraviolet B ◽  
Controlled Environment ◽  
Light Sources ◽  
Color Development ◽  
Primary Driver ◽  
Uvb Exposure ◽  
Environment Chamber

The market value of the apple (Malus ×domestica Borkh.) cultivar Ambrosia is closely linked to the characteristic blush on the skin surface. For ‘Ambrosia’ orchards that produce consistently low levels of surface blush, the implementation of reflective rowcovering has improved surface coloration, but the reflected wavebands responsible for this enhanced color production have not been confirmed. This study consisted of two separate experiments: one conducted in the field to confirm reflective rowcovering efficacy and the other in a controlled environment cabinet to determine which waveband was enhancing red blush production. The red blush production in orchards with and without reflective rowcovering was then directly compared with the red blush produced on the surface of apples that were poorly colored at harvest and then exposed to visible, fluorescent, ultraviolet A (UVA), or ultraviolet B (UVB) light sources within the controlled environment chamber. Consequent analysis of the red blush color within the Commission Internationale de l’Eclairage a* and b* color space was conducted to evaluate the quality of the red blush pigment under each treatment in the field and the controlled environment chamber. The analysis revealed that the red blush that developed on apples from the reflective rowcover treatment most closely matched the red blush that developed in response to UVB exposure in the controlled environment cabinet. Further analysis of gene expression and anthocyanin contents in the ‘Ambrosia’ apples support the hypothesis that the primary driver for the characteristic red blush development, when reflective rowcovers are used, is increased exposure to UVB light.

scholarly journals The eye status in patients after new coronavirus infection

2020 ◽  
Vol 48 ◽  
pp. 20-26
Author(s):  
A. A. Ryabtseva ◽  
E. E. Grishina ◽  
O. M. Andryukhina ◽  
A. A. Kovrizhkina ◽  
A. S. Andryukhina
Keyword(s):  
Clinical Manifestations ◽  
Color Perception ◽  
Rapid Progression ◽  
Light Sources ◽  
Ophthalmological Examination ◽  
Dry Eyes ◽  
Department Of Ophthalmology ◽  
Coronavirus Infection ◽  
Fluorescence Contrast ◽  
Auto Fluorescence

Rationale: The emerging new coronavirus infection caused by SARS-CoV-2 has resulted in a pandemic. Its clinical manifestations are highly variable and the death rate is high due to rapid progression to acute respiratory distress syndrome. Identified abnormalities of the eye are mainly related to conjunctival injury during manifestation of the disease.Aim: To study the eye abnormalities in patients who have undergone COVID-19.Materials and methods: Ophthalmological examination was performed in 23 patients (6 [26%] men and 17 [74%] women, median age 42.39 years) at days 44 to 85 after manifestation of COVID-19 infection in the Department of Ophthalmology, MONIKI. In addition to the standard ophthalmological examination, all patients were evaluated with optical coherence tomography (OCT), auto fluorescence, contrast and color sensitivity test with different light sources, and tear production assessment.Results: In the late convalescence period there were complaints of dry eyes and abnormal color perception, with visual acuity being unchanged. The OCT assessment the peripapillary retina identified small hyper-reflective foci in the inner layers.Conclusion: Eye disease in patients after COVID-19 is mainly related to the condition of the eye surface, abnormal color perception and abnormal architectonics of the inner retinal layers, which can persist for a long time during convalescence.

scholarly journals Wild hummingbirds discriminate nonspectral colors

2020 ◽  
Vol 117 (26) ◽  
pp. 15112-15122 ◽  
Author(s):  
Mary Caswell Stoddard ◽  
Harold N. Eyster ◽  
Benedict G. Hogan ◽  
Dylan H. Morris ◽  
Edward R. Soucy ◽  
...  
Keyword(s):  
Spectral Sensitivity ◽  
Uv Light ◽  
Monochromatic Light ◽  
Color Space ◽  
Color Perception ◽  
Color Discrimination ◽  
Behavioral Experiments ◽  
Simultaneous Stimulation ◽  
Cone Type ◽  
Sensitivity Curves

Many animals have the potential to discriminate nonspectral colors. For humans, purple is the clearest example of a nonspectral color. It is perceived when two color cone types in the retina (blue and red) with nonadjacent spectral sensitivity curves are predominantly stimulated. Purple is considered nonspectral because no monochromatic light (such as from a rainbow) can evoke this simultaneous stimulation. Except in primates and bees, few behavioral experiments have directly examined nonspectral color discrimination, and little is known about nonspectral color perception in animals with more than three types of color photoreceptors. Birds have four color cone types (compared to three in humans) and might perceive additional nonspectral colors such as UV+red and UV+green. Can birds discriminate nonspectral colors, and are these colors behaviorally and ecologically relevant? Here, using comprehensive behavioral experiments, we show that wild hummingbirds can discriminate a variety of nonspectral colors. We also show that hummingbirds, relative to humans, likely perceive a greater proportion of natural colors as nonspectral. Our analysis of plumage and plant spectra reveals many colors that would be perceived as nonspectral by birds but not by humans: Birds’ extra cone type allows them not just to see UV light but also to discriminate additional nonspectral colors. Our results support the idea that birds can distinguish colors throughout tetrachromatic color space and indicate that nonspectral color perception is vital for signaling and foraging. Since tetrachromacy appears to have evolved early in vertebrates, this capacity for rich nonspectral color perception is likely widespread.

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