Manuel Melgosa

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The CMC, BFD, and CIE94 color-difference formulas have been compared throughout their weighting functions to the CIELAB components ⌬L*, ⌬C*, ⌬H*, and from their performance with respect to several wide data-sets from old and recent literature. Predicting the magnitude of perceived color differences, a statistically significant improvement upon CIELAB should(More)
CIELAB-based color-difference formulas are used to improve the prediction of visually perceived color differences through the introduction of various corrections to CIELAB. In our study we analyze the relative importance of these corrections. From the combined dataset employed for the development of CIEDE2000, we found that the improvement of CIE94 over(More)
The RIT–DuPont visual color-difference data as the RIT–DuPont data set, and they are the basis for [Color Res. Appl. 16, 297–316 (1991)] have been used our current analyses. to estimate contours of equal color-differences (ellip-The RIT–DuPont data set consists of 156 tolerances, soids) at 19 color centers, in CIELAB and x, y, Y/100 each of equal visual(More)
An investigation of the color metrics and the complexity of the CIEDE2000 formula shows that CIELAB space is inadequate to represent small-medium color differences. The OSA-UCS (Uniform Color Space) Committee has shown that no space with uniform scale for large color differences exists. Therefore the practical way for color-difference specification is a(More)
In this article, we report new color discrimination ellipsoids calculated from two normal observers, using a CRT device and five values of luminance at each of the five centers recommended by the CIE in 1978 (Col Res Appl 1978;3:149 –151). Our main goal was to test the weighting function for lightness adopted by the CIE94 color-difference model (CIE(More)
We propose a new approach to the quantitative determination of the iris colour through the spectroradiometric measurement of a set of 72 artificial irises under controlled illumination and geometry. The spread of these samples in the CIELAB colour space indicates no clearly distinguished groups within the set analysed. Colour measurements for different(More)
We have analyzed the way in which simulated textures made of random dots influence visual suprathreshold color tolerances. We considered 32 textures created by a systematic variation of the following variables: size, number, and color of the dots. Each texture was mapped on the five centers recommended by the International Commission on Illumination (CIE)(More)
A total of 21 raw, washed and ground Spanish kaolins were studied. Kaolinite, mica, quartz, feldspars and occasionally anatase and analcime were present. Calcined samples in which the kaolinite had been transformed into metakaolinite (650 8C, 3 h), as shown by X-ray diffraction and observed using SEM were also studied. These samples featured particles with(More)
Commercial talcs are pulverized mineral products with a variable chemical and mineralogic composition, widely used in industry. Although generally white, they have color variations. The aim of this study was to establish relationships between color parameters and the chemical and mineralogic composition of commercial talc samples, in order to investigate(More)