ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00051.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00052.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Recent algorithms developed in the field of color vision make assumptions based on the spectral reflectance curves of Munsell chips and natural materials. Some of them rely on data collected many years ago. which is partially incomplete in the visible spectrum. or contains many occurrences of the same material in it. In this article. we present a set of new measurements of different materials. In particular. we measured the spectral reflectance of Munsell chips, paints. and various natural materials in the 390–730‐nm range. In addition, we have analyzed. through principal‐component analysis, the possibility of representing the data collected with a set of basis functions. We show the implications of varying the number of principal components used (from 7 down to 3) on the errors introduced using this m

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00053.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Departures from exact ellipticity when color‐discrimination ellipsoids or ellipses are translated to CIELAB have been numerically analyzed. The greatest distortions for ellipses were around 5% at the most saturated orange‐red centers. The distortions for ellipsoids were of the same order as those of the ellipses at the five CIE centers. These small distortions are well covered by the interobserver variability and could be ignored in most cases, but an appropriate method must be used for the translation of color‐threshold results to CIELAB. Experimental results published by Luo and Rigg for 132 chromaticity‐discrimination ellipses are expressed in CIELAB. These results may be useful in checking the performance of new color‐difference

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00054.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

In the present work the colour coordinates have been obtained in the CIELAB system (L*,a*,b*) for the teeth of 600 individuals. to determine the region of the CIELAB space which contains all the different hues found in human teeth. In addition. one of the colour guides most used in dentistry has been studied to compare the hue range in this guide with the range possible in human teeth. The results show that colour coordinates of human teeth fall within an elliptical contour centered in a yellowish white. The colour guide studied did not cover all the possible values found for teeth chromaticities.

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00055.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

An improved predictor of colourfulness in the Hunt 91 model of colour vision is described. A new chroma predictor allows for the effect of the luminance Jactor of the background more effectively, and results in more consistent predictions for different viewing conditions. The new colourfulness predictor is obtained by multiplying the new chroma predictor by a factor that varies more slowly with the level of adapting luminance than was the case for the old colourfulness predictor; this results in much better predictions, whose coefficients of variation are similar to those that characterize observer consistency. The steps required for reversing the model are given in an appendix.

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00056.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Coefficients of variation that show the degree to which the Hunt model of colour vision is successful in predicting the LUTCRI appearance data are gathered together in this article for a very wide range of viewing conditions. The model now consistently predicts these data as closely as the results of a single observer. agree with the average results of a group of six observers. The nature of the adjustments that have had to be made to the model to achieve this result are described. and their implications are discussed.

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00057.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Metelli's theory of the perception of translucency models the effective reflectance of a translucent sheet on a background as a partitive mixture of the color of the sheet and the color of the background. In the achromatic case, the usable (that is, scale‐invariant) rules governing the apparent reflectances are the same as those that would emerge from the Kubelka‐Munk theory. For chromatic translucency, the relationships are more complex, but a set of rules still emerge from the partitive‐mixture theory that are invariant to tradeoffs between illuminant and reflectances. This column sets forth the rules in the hopes that they will have graphical applications, both on computer VDUs and in har

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00058.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00059.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0361-2317    

DOI:10.1111/j.1520-6378.1994.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY