scholarly journals Investigation of CIE color spaces for differences in color differentiation thresholds in different regions of the color locus

2021 ◽  
Vol 24 (3) ◽  
pp. 107-110
Author(s):  
Leonid D. Lozhkin ◽  
Alexander A. Kuzmenko
Keyword(s):  
Visual Perception ◽  
Significant Role ◽  
Color Space ◽  
Color Difference ◽  
International Commission ◽  
Color Spaces ◽  
Transmission Systems ◽  
Color Coordinates ◽  
Cie Lab

The equidistance of the color space plays a significant role in determining the color difference in color transmission systems. Strictly equal contrasting color spaces can be considered only those color spaces in which equal changes in the visual perception of color are provided with an equal change in the color coordinates in this color space. Currently, the International Commission on Lighting (CIE) has adopted a number of color spaces called equal-contrast. The article presents the results of the study of color spaces adopted by CIE for equal contrast, i.e. on the differences in the thresholds of color differentiation in different areas of the color locus. The article investigated such color spaces as CIE 1931 (RGB), CIE 1931 (x, y), CIE 1960 (u, v), CIE 1976 (u*, v*), CIE LAB (a*, b*).

The Color Recognition of Jet Fuel Silver Corrosion Images Based on Color Difference Formula

2012 ◽  
Vol 503-504 ◽  
pp. 1033-1036
Author(s):  
Li Ping Tong ◽  
Bin Peng ◽  
Yi Wei Fei
Keyword(s):  
Color Space ◽  
Color Difference ◽  
Recognition System ◽  
Jet Fuel ◽  
Color Spaces ◽  
Object Surface ◽  
Television System ◽  
Color Recognition ◽  
Difference Formula ◽  
Cie Lab

This article introduces the basic theoretical knowledge of the multi-color space and its color difference formula. By research and experiment, it validates that HSV and CIE L * a * b * color space and its corresponding color difference formula, which are used in the color recognition of jet fuel silver corrosion image, and their results are mostly in accordance with the recognition results by the naked eyes. And it also proves the feasibility of these two methods for the color recognition of jet fuel silver corrosion. Silver strip corrosion experiment must be tested as one of jet fuel corrosion detection items in jet fuel accepting, providing and storage process. The examination, whether jet fuel is qualified or not, is mainly due to silver corrosion’s color judgment. For computer visual system, the color is the character of object surface, and it is mankind recognition system to the object surface, light shine and visual condition’s comprehensive effect, and it has important function in the picture’s partition and identifying field. The color that is put up by visible light is continuous, and in order to measure and calculate conveniently, some scholars successively establish more than ten color spaces, which are mainly divided three types, by the HSV color space with RGB, HIS, and Munsell color spaces etc. According to particular application color space, YUV and YIQ and CMY color space are adopted by the television system, and CIE color space then includes CIE, XYZ, Lab and Luv etc. This article comparatively studies representative color space as well as RGB, HIS, CMY, YUV and CIE Lab color spaces, which are used for jet fuel silver strip corrosion image’s color recognition accuracy, and this article finally ensures a kind of color space and color difference formula which are applied to jet fuel silver strip corrosion image’s color recognition.

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 Mathematics and practice of color space invariants by the example of determining the gray balance for a digital printing system

2020 ◽  
Vol 44 (1) ◽  
pp. 117-126 ◽  
Author(s):  
D.A. Tarasov ◽  
O.B. Milder
Keyword(s):  
Color Space ◽  
Analytical Description ◽  
Digital Printing ◽  
Mutual Transformation ◽  
Color Spaces ◽  
Practical Application ◽  
Printing System ◽  
Cie Lab ◽  
Electrophotographic Printing ◽  
Spatial Curves

In modern printing, a large number of tasks are associated with the mutual transformation of color spaces. In particular, the most common pair of hardware-dependent color spaces is RGB and CMYK, the mutual transformation of colors in which is ambiguous, which creates significant problems in color reproduction. To solve this problem, we propose using color space invariants — gradation trajectories and gradation surfaces, which are analogs of gradation curves for initial colorants and their binary overlays, constructed in the absolute color space of the CIE Lab. Invariants are introduced on the basis of the mathematical apparatus of the differential geometry of spatial curves and surfaces. Practical application of color space invariants involves certain difficulties associated with their complex analytical description; moreover, for most practical problems, the high accuracy of the model is redundant. For the practical application of invariants, we propose a simpler approach using natural color sampling in digital printing systems. As an example, the procedure for determining the gray balance for an electrophotographic printing press is given.

Analysis of SSIM Based Quality Assessment across Color Channels of Images

2015 ◽  
pp. 1233-1245
Author(s):  
T. Chandrakanth ◽  
B. Sandhya
Keyword(s):  
Image Processing ◽  
Quality Assessment ◽  
Color Space ◽  
Similarity Index ◽  
Human Perception ◽  
Structural Similarity ◽  
Subjective Assessment ◽  
Color Images ◽  
Color Spaces ◽  
Cie Lab

Advances in imaging and computing hardware have led to an explosion in the use of color images in image processing, graphics and computer vision applications across various domains such as medical imaging, satellite imagery, document analysis and biometrics to name a few. However, these images are subjected to a wide variety of distortions during its acquisition, subsequent compression, transmission, processing and then reproduction, which degrade their visual quality. Hence objective quality assessment of color images has emerged as one of the essential operations in image processing. During the last two decades, efforts have been put to design such an image quality metric which can be calculated simply but can accurately reflect subjective quality of human perception. In this paper, the authors evaluated the quality assessment of color images using SSIM (structural similarity index) metric across various color spaces. They experimented to study the effect of color spaces in metric based and distance based quality assessment. The authors proposed a metric using CIE Lab color space and SSIM, which has better correlation to the subjective assessment in a benchmark dataset.

Influence of Fe2+ on the Color Appearance of Yellow-Green Peridot

2011 ◽  
Vol 492 ◽  
pp. 370-373 ◽  
Author(s):  
Wei Xi Tang ◽  
Ying Guo ◽  
Li Xia Ma
Keyword(s):  
Color Space ◽  
Chromatic Aberration ◽  
Color Difference ◽  
Color Appearance ◽  
Chemical Compositions ◽  
Significance Level ◽  
Icp Ms ◽  
Difference Formula ◽  
Chromaticity Coordinates ◽  
Cie Lab

Twenty-eight yellow-green color of uniform, high clarity and similar thickness of 5 mm × 7 mm oval faceted peridots from Jiaohe Jilin province were examined by LA-ICP-MS and Color i5 to test their chemical compositions and L*, C* and ho. The correlations between Fe2+ and color parameters were analyzed, in order to establish the influence on the color appearance of Fe2+. The chemical formula of the twenty-eight peridots is (Mg1.84,Fe0.19)2.04[(Si0.982,Al0.001)0.983O4], which was calculated by oxygen atom. It reveals that 0.19 mol Fe2+ is concluded in one mol peridot, and Fe2+ is the colorant of peridot. Based on the CIE 1976 L*a*b* uniform color space, relationships between chromaticity coordinates a*, b* and chromaticity C* were analyzed by Two-way ANOVA, of which the results showing that the influence of b* on C* (rb*×C*=0.996) is much more prominent than a* on C* (ra*×C*= -0.383). By partial correlation analysis of the results calculated through CIE LAB color-difference formula, it can be discovered that lightness difference DL* has a better correlation with chromatic aberration DE* than DC* and DH*, whereas the significance level ρDC*×DE* > 0.05, rDH*×DE* > 0.05, it reveals that DE* is more sensitive to DL*. At the same time, L* changes the most with the contributions of Fe2+ compared with other parameters of peridot. It is concluded that, with the help of L*, Fe2+ has a further influence on the color appearance of peridot.

scholarly journals The Geometry of Colors in Van Gogh’s Sunflowers

2021 ◽  
Author(s):  
Shuting Liao ◽  
Patrice Koehl ◽  
Jennifer Schultens ◽  
Fushing Hsieh
Keyword(s):  
Data Science ◽  
Color Space ◽  
Computational Approach ◽  
Regions Of Interest ◽  
Color Spaces ◽  
Van Gogh ◽  
Color Coordinates ◽  
Positive Shift ◽  
Blue Component ◽  
The Impact

Abstract “Paintings fade like flowers”: van Gogh’s prediction on the impact of age on paintings came true for most of his paintings. We have studied the consequences of this aging on the Sunflowers in a vase with a yellow background series, namely its original, F454, and two replicates, F457 and F458, at the van Gogh’s museum in Amsterdam, which van Gogh painted using the original as a model. The background and flower renditions in those paintings have faded and turned brown, making them less vibrant that van Gogh had most likely intended. We have attempted to restore van Gogh’s intent using a computational approach based on data science. After identifications of regions of interest (ROI) within the three paintings F454, F457, and F458 that capture the flowers, stems of the flowers, and background, respectively, we studied the geometry of the color space (in RGB representation) occupied by those ROIs. By comparing those color spaces with those occupied by similar ROIs in photographs of real sunflowers, we identified shifts in all three color coordinates, R, G, and B, with the positive shift in the blue coordinate being the more salient. We have proposed two algorithms, PCR-1 and PCR-2, for correcting that shift in blue and generate representations of the paintings that aim to restore their original conditions. The reduction of the blue component in the yellow hues has lead to more vibrant and less brownish digital rendition of the three Sunflowers in a vase with a yellow background.

scholarly journals A Quantitative Method for Estimation of Quality of Screens Color

2018 ◽  
pp. 39-46
Author(s):  
O. Kupko
Keyword(s):  
Visual Perception ◽  
Color Space ◽  
Three Dimensional ◽  
Dimensional Case ◽  
Two Dimensional ◽  
Color Spaces ◽  
Human Visual Perception ◽  
Insufficient Amount ◽  
History Of ◽  
The Difference

The history of the issue on creation of uniform color spaces is analyzed. It is noted that the calculations based on the results of spectral measurements do not adequately correspond to the human visual perception. For all existing color spaces, it has been proposed to create a uniform metric, a me­thod for determining the length, area and volume in the corresponding spaces, one that corresponds to the human visual perception. The metric is based on MacAdam ellipses, that is, on the threshold perception of the difference in colors. For each point of any color space (two or three measurements) is determined the area of space around each point, within which a person is not able to fix the difference in color. The area is characterized by either an ellipse (two-dimensional case) or an ellipsoid (three-dimensional case). To characterize an ellipse, it is necessary to have three parameters — two axes and the angle of slope. To characterize an ellipsoid, it is necessary to have five parameters — three axes and two angle of slope. The number of sections along a line, along a plane, or in a volume is a measure of length, a plane, or in a volume and sets a metric. The connection of the existing systems for determining color and visual perception of a person is carried out using scales. Scales associate the length, area or volume of any color system with a person’s visual perception. The scale depends on the point of space and the direction in which the movement takes place. As a result, a large number of scales (more than the number of colors, because it is necessary to know the angles of inclination of the ellipses) are needed, which must be agreed by the international community. To use this amount of data and for the corresponding calculations, it is necessary to have an agreed international calculation procedure. It is established, that as a result of the development of computing technology, a large amount of data and a large amount of computation are not a significant obstacle. The obstacle is an insufficient amount of consistent data, that is, it is necessary to perform additional measurements and approvals to determine the areas of space around each point of the color space within which a person is not able to fix the difference in color. A schematic diagram of the measurements and the equipment with the help of which it is possible to carry out the corresponding measurements are proposed. Estimates of the greatest labour intensity of such works are carried out. It is determined what is the most important part of these works is possible to carry out within a few years. For two-dimensional spaces (x, y and u, v), using the results of the classical work of McAdam, we determined the scales for connecting the lengths and areas in these spaces with the visual perception of the human eye. The directions in which the scales are largest or smallest are determined. For these two directions there are given scales that relate the distances and areas of the spaces (x,y and u,v) with the human visual perception. It is noted, that the work on creating the metrics has a clear phased structure, some parts of the work, i.e.: the development of software and programming, the development of stabilized radiation sources, the development of comparing tools and experimental research can be carried out independently. Conclusions and suggestions are made.

scholarly journals How Good Are RGB Cameras Retrieving Colors of Natural Scenes and Paintings?—A Study Based on Hyperspectral Imaging

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6242
Author(s):  
João M. M. Linhares ◽  
José A. R. Monteiro ◽  
Ana Bailão ◽  
Liliana Cardeira ◽  
Taisei Kondo ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Spectral Sensitivity ◽  
Color Space ◽  
Color Difference ◽  
The Other ◽  
Spectral Information ◽  
Natural Scenes ◽  
Digital Cameras ◽  
Color Spaces ◽  
Open Question

RGB digital cameras (RGB) compress the spectral information into a trichromatic system capable of approximately representing the actual colors of objects. Although RGB digital cameras follow the same compression philosophy as the human eye (OBS), the spectral sensitivity is different. To what extent they provide the same chromatic experiences is still an open question, especially with complex images. We addressed this question by comparing the actual colors derived from spectral imaging with those obtained with RGB cameras. The data from hyperspectral imaging of 50 natural scenes and 89 paintings was used to estimate the chromatic differences between OBS and RGB. The corresponding color errors were estimated and analyzed in the color spaces CIELAB (using the color difference formulas ΔE*ab and CIEDE2000), Jzazbz, and iCAM06. In CIELAB the most frequent error (using ΔE*ab) found was 5 for both paintings and natural scenes, a similarity that held for the other spaces tested. In addition, the distribution of errors across the color space shows that the errors are small in the achromatic region and increase with saturation. Overall, the results indicate that the chromatic errors estimated are close to the acceptance error and therefore RGB digital cameras are able to produce quite realistic colors of complex scenarios.

Analysis of SSIM based Quality Assessment across Color Channels of Images

2015 ◽  
Vol 4 (3) ◽  
pp. 30-42 ◽  
Author(s):  
T. Chandrakanth ◽  
B. Sandhya
Keyword(s):  
Image Processing ◽  
Quality Assessment ◽  
Color Space ◽  
Similarity Index ◽  
Human Perception ◽  
Structural Similarity ◽  
Subjective Assessment ◽  
Color Images ◽  
Color Spaces ◽  
Cie Lab

Advances in imaging and computing hardware have led to an explosion in the use of color images in image processing, graphics and computer vision applications across various domains such as medical imaging, satellite imagery, document analysis and biometrics to name a few. However, these images are subjected to a wide variety of distortions during its acquisition, subsequent compression, transmission, processing and then reproduction, which degrade their visual quality. Hence objective quality assessment of color images has emerged as one of the essential operations in image processing. During the last two decades, efforts have been put to design such an image quality metric which can be calculated simply but can accurately reflect subjective quality of human perception. In this paper, the authors evaluated the quality assessment of color images using SSIM (structural similarity index) metric across various color spaces. They experimented to study the effect of color spaces in metric based and distance based quality assessment. The authors proposed a metric using CIE Lab color space and SSIM, which has better correlation to the subjective assessment in a benchmark dataset.

scholarly journals Color Calibration for Colorized Vision System with Digital Sensor and LED Array Illuminator

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Zhenmin Zhu ◽  
Ruichao Song ◽  
Hui Luo ◽  
Jun Xu ◽  
Shiming Chen
Keyword(s):  
Vision System ◽  
Color Space ◽  
Color Difference ◽  
Regression Method ◽  
Color Measurement ◽  
Color Spaces ◽  
Color Calibration ◽  
Led Array ◽  
Tristimulus Values ◽  
Spectral Responses

Color measurement by the colorized vision system is a superior method to achieve the evaluation of color objectively and continuously. However, the accuracy of color measurement is influenced by the spectral responses of digital sensor and the spectral mismatch of illumination. In this paper, two-color vision system illuminated by digital sensor and LED array, respectively, is presented. The Polynomial-Based Regression method is applied to solve the problem of color calibration in the sRGB andCIE  L⁎a⁎b⁎color spaces. By mapping the tristimulus values from RGB to sRGB color space, color difference between the estimated values and the reference values is less than3ΔE. Additionally, the mapping matrixΦRGB→sRGBhas proved a better performance in reducing the color difference, and it is introduced subsequently into the colorized vision system proposed for a better color measurement. Necessarily, the printed matter of clothes and the colored ceramic tile are chosen as the application experiment samples of our colorized vision system. As shown in the experimental data, the average color difference of images is less than6ΔE. It indicates that a better performance of color measurement is obtained via the colorized vision system proposed.

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