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Huang M.,Beijing Institute of Graphic Communication | Liu H.,Beijing Institute of Graphic Communication | Cui G.,VeriVide Ltd | Luo M.R.,University of Leeds | Melgosa M.,University of Granada
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2012

The performances of uniform color spaces and color-difference formulae for predicting threshold color differences were investigated based on visual assessments of 893 pairs of printed color patches under a D65 source. The average δEab;10 of the pairs was 1.1 units. A threshold psychophysical experiment was repeated three times by a panel of 16 observers with normal color vision. The experimental data were used to evaluate nine color-difference formulae and uniform color spaces using the standardized residual sum of squares (STRESS) measure. The results indicated that all formulae and spaces performed very similarly to each other, and outperformed CIELAB for threshold color differences. The chromaticity-discrimination ellipses were used to compare with previous results from small color differences [Color Res. Appl. (2011), doi:10.1002/col.20689], and they agreed with each other, except for the purple color center. © 2012 Optical Society of America. Source


Liu H.,Beijing Institute of Graphic Communication | Huang M.,Beijing Institute of Graphic Communication | Wu B.,Beijing Institute of Graphic Communication | Cui G.,VeriVide Ltd | Ronnier Luo M.,Zhejiang University
Guangxue Xuebao/Acta Optica Sinica | Year: 2012

Two psychophysical experiments, experiment I and experiment II, were conducted to test color difference calculation method in images. Five ISO SCID images were used as test images and the test image pairs were displayed on EIZO CG 19 monitors. The computed color difference with CIELAB, CIEDE2000, CIE94 and CMC formulae showed that the calculated color difference in lightness and chroma attributes behaved very differently and the color image contents had some effects on the color sensation. An optimization method of color difference formulae is proposed based on the experiment I data. The optimized formulae CIELAB(1.50:1), CIEDE2000(2.29:1), CIE94(3.04:1) and CMC(3.38:1) perform much better than the original one and CIEDE2000(2.29:1) is the best among the four. The optimized formulae are also tested by the experiment II data, which proves that the optimized method proposed is accurate, simple and practical. Source


Huang M.,Beijing Institute of Graphic Communication | Liu H.,Beijing Institute of Graphic Communication | Cui G.,VeriVide Ltd | Ronnier L.M.,Zhejiang University
Guangxue Xuebao/Acta Optica Sinica | Year: 2012

A series of experiments are conducted using printing samples to investigate the effects of different gloss and different color-difference magnitudes. The results are used to reveal these effects. In addition, seven different color spaces basded on CIELAB DIN99, OSA and CIECAM02 are tested using these data. It is found that comparing the performance of local uniformity and global uniformity, OSA-Gp-Eu and DIN99d always perform the best, and all spaces outperform CIELAB and OSA. Source


Panthee D.R.,North Carolina State University | Perkins-Veazie P.,North Carolina State University | Randall D.,VeriVide Ltd | Brown A.F.,North Carolina State University
International Journal of Vegetable Science | Year: 2013

The color of red tomatoes (Solanum lycopersicum L.) is mostly from the carotenoid pigment lycopene, which is of interest to consumers and the tomato industry because of its purported protective effects against diabetes, cardiovascular events, and some cancers. Lycopene content was measured in at least 179 tomato lines with pink, red, and dark red fruit derived from a diverse genetic background to determine the level of variation for lycopene and to develop prediction models. Two methods (Tomato Analyzer or DigiEye) for quantifying total lycopene and to develop prediction models were tested on tomato fruit to find a high throughput lycopene measurement system suitable for screening hundreds of lines in a breeding program. The tomato lycopene content ranged from 28 to 133 mg•kg-1 of tomato sample, indicating a wide variation in the set of tomato lines. Using this variation, lycopene prediction models were developed. Though a single equation could not be developed using data from the DigiEye or Tomato Analyzer to predict lycopene content of tomato fruit, individual equations within color groups proved useful in predicting lycopene content (r = 0.77, P < 0.05). Our data indicate that rapid analysis of tomato fruit, kept relatively intact, can be done to accurately predict lycopene content in a wide range of fruit colors. Current address for Dan Randall: Shaw Industries Inc., 200 Industrial Blvd., Bainbridge, GA 39817. © 2013 Copyright Taylor and Francis Group, LLC. Source


Ji W.,University of Leeds | Koutsidis G.,Northumbria University | Luo R.,Zhejiang University | Luo R.,University of Leeds | And 4 more authors.
Color Research and Application | Year: 2013

Visually assessed appearance is undoubtedly of great importance to the selection of fruit by the consumer at the point of sale while the food supply chain also heavily relies on colour assessment methodologies for the determination of product quality. The use of printed colour charts to assess the ripening stages of fruits (i.e., banana ripeness charts) and/or vegetables is common in the fresh produce supply chain, even though they have limitations. However, the development of a more reliable and an objective instrumental method is necessary to describe fruit ripeness using set colour appearance parameters rather than subjective evaluations based on colour charts. In this article, we report a novel digital imaging methodology that could be used by the fresh produce industry to estimate the ripening stages of bananas more accurately. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 364-374, 2013 Copyright © 2012 Wiley Periodicals, Inc. Source

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