The aims of this study are to develop the color density concept and to propose the color density based color difference formulas.The color density is defined using the metric coefficients that are based on the discrim...The aims of this study are to develop the color density concept and to propose the color density based color difference formulas.The color density is defined using the metric coefficients that are based on the discrimination ellipses and the locations of the colors in the color space.The ellipse sets are the MacAdam ellipses in the CIE 1931 xy-chromaticity diagram and the chromaticity-discrimination ellipses in the CIELAB space.The latter set was originally used to develop the CIEDE2000 color difference formula.The color difference can be calculated from the color density for the two colors under consideration.As a result,the color density represents the perceived color difference more accurately,and it could be used to characterize a color by a quantity attribute matching better to the perceived color difference from this color.Resulting from this,the color density concept provides simply a correction term for the estimation of the color differences.In the experiments,the line element formula and the CIEDE2000 color difference formula performed better than the color density based difference measures.The reason behind this is in the current modeling of the color density concept.The discrimination ellipses are typically described with three-dimensional data consisting of two axes,the major and the minor,and the inclination angle.The proposed color density is only a one-dimensional corrector for color differences;thus,it cannot capture all the details of the ellipse information.Still,the color density gives clearly more correct estimations to perceived color differences than Euclidean distances using directly the coordinates of the color space.展开更多
To investigate the applicability of four commonly used color difference formulas(CIELAB,CIE94,CMC(1:1),and CIEDE2000)in the printing field on 3D objects,as well as the impact of four standard light sources(D65,D50,A,a...To investigate the applicability of four commonly used color difference formulas(CIELAB,CIE94,CMC(1:1),and CIEDE2000)in the printing field on 3D objects,as well as the impact of four standard light sources(D65,D50,A,and TL84)on 3D color difference evaluations,50 glossy spheres with a diameter of 2cm based on the Sailner J4003D color printing device were created.These spheres were centered around the five recommended colors(gray,red,yellow,green,and blue)by CIE.Color difference was calculated according to the four formulas,and 111 pairs of experimental samples meeting the CIELAB gray scale color difference requirements(1.0-14.0)were selected.Ten observers,aged between 22 and 27 with normal color vision,were participated in this study,using the gray scale method from psychophysical experiments to conduct color difference evaluations under the four light sources,with repeated experiments for each observer.The results indicated that the overall effect of the D65 light source on 3D objects color difference was minimal.In contrast,D50 and A light sources had a significant impact within the small color difference range,while the TL84 light source influenced both large and small color difference considerably.Among the four color difference formulas,CIEDE2000 demonstrated the best predictive performance for color difference in 3D objects,followed by CMC(1:1),CIE94,and CIELAB.展开更多
To deduce a new color difference formula based on CIE 1997 Color Appearance Model(CIECAM97s), a color space J a 1 b 1 is first constructed with color appearance descriptors J,a,b in CIECAM97s. The new f...To deduce a new color difference formula based on CIE 1997 Color Appearance Model(CIECAM97s), a color space J a 1 b 1 is first constructed with color appearance descriptors J,a,b in CIECAM97s. The new formula is then deduced in the space and named CDF CIECAM97s. The factors for lightness, chroma and hue correction in the formula are derived by linear regression according to BFD? CP data sets. It is found by statistical analysis that CDF CIECAM97s is in closer accordance with the visual assessments when compared with CMC(1∶1), CIE94 and CIE L *a *b * color difference formulae. Based on color appearance model, the new color difference formula can be used to predict color difference perception in a varity of different viewing conditions.展开更多
The chroma difference(DC)and lightness difference(DL)of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~...The chroma difference(DC)and lightness difference(DL)of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~*b^~*to evaluate their contribution to the color appearance and color difference(DE).展开更多
文摘The aims of this study are to develop the color density concept and to propose the color density based color difference formulas.The color density is defined using the metric coefficients that are based on the discrimination ellipses and the locations of the colors in the color space.The ellipse sets are the MacAdam ellipses in the CIE 1931 xy-chromaticity diagram and the chromaticity-discrimination ellipses in the CIELAB space.The latter set was originally used to develop the CIEDE2000 color difference formula.The color difference can be calculated from the color density for the two colors under consideration.As a result,the color density represents the perceived color difference more accurately,and it could be used to characterize a color by a quantity attribute matching better to the perceived color difference from this color.Resulting from this,the color density concept provides simply a correction term for the estimation of the color differences.In the experiments,the line element formula and the CIEDE2000 color difference formula performed better than the color density based difference measures.The reason behind this is in the current modeling of the color density concept.The discrimination ellipses are typically described with three-dimensional data consisting of two axes,the major and the minor,and the inclination angle.The proposed color density is only a one-dimensional corrector for color differences;thus,it cannot capture all the details of the ellipse information.Still,the color density gives clearly more correct estimations to perceived color differences than Euclidean distances using directly the coordinates of the color space.
文摘To investigate the applicability of four commonly used color difference formulas(CIELAB,CIE94,CMC(1:1),and CIEDE2000)in the printing field on 3D objects,as well as the impact of four standard light sources(D65,D50,A,and TL84)on 3D color difference evaluations,50 glossy spheres with a diameter of 2cm based on the Sailner J4003D color printing device were created.These spheres were centered around the five recommended colors(gray,red,yellow,green,and blue)by CIE.Color difference was calculated according to the four formulas,and 111 pairs of experimental samples meeting the CIELAB gray scale color difference requirements(1.0-14.0)were selected.Ten observers,aged between 22 and 27 with normal color vision,were participated in this study,using the gray scale method from psychophysical experiments to conduct color difference evaluations under the four light sources,with repeated experiments for each observer.The results indicated that the overall effect of the D65 light source on 3D objects color difference was minimal.In contrast,D50 and A light sources had a significant impact within the small color difference range,while the TL84 light source influenced both large and small color difference considerably.Among the four color difference formulas,CIEDE2000 demonstrated the best predictive performance for color difference in 3D objects,followed by CMC(1:1),CIE94,and CIELAB.
文摘To deduce a new color difference formula based on CIE 1997 Color Appearance Model(CIECAM97s), a color space J a 1 b 1 is first constructed with color appearance descriptors J,a,b in CIECAM97s. The new formula is then deduced in the space and named CDF CIECAM97s. The factors for lightness, chroma and hue correction in the formula are derived by linear regression according to BFD? CP data sets. It is found by statistical analysis that CDF CIECAM97s is in closer accordance with the visual assessments when compared with CMC(1∶1), CIE94 and CIE L *a *b * color difference formulae. Based on color appearance model, the new color difference formula can be used to predict color difference perception in a varity of different viewing conditions.
文摘The chroma difference(DC)and lightness difference(DL)of 288 jadeite-jades with fine texture and even green color have been analyzed based on color difference formula CIE LAB in the uniform color space CIE 1976 L^~*a^~*b^~*to evaluate their contribution to the color appearance and color difference(DE).
