The cellular Yule-Nielson spectral Neugebauer （CYNSN） model to characterize a typical CMYK （i.e.,cyan,magenta,yellow,and black） 4-ink color printer is presented.By reconstructing spectral reflectance,models with h...The cellular Yule-Nielson spectral Neugebauer （CYNSN） model to characterize a typical CMYK （i.e.,cyan,magenta,yellow,and black） 4-ink color printer is presented.By reconstructing spectral reflectance,models with high accuracy of spectral and colorimetric predictions are built.A novel cell-searching algorithm is proposed and used together with the iteration method to invert the cellular Neugebauer model efficiently.Large numbers of high quality hardcopy samples are produced to evaluate model performance and prove the feasibility of the algorithm.The spectral-based model performs better compared with the usual model based on CIE1931 XYZ tristimulus values.展开更多
Seven color separation criteria are evaluated and compared for multi-ink printer characterization, which is a union of five 3-ink and six 4-ink cellular Yule-Nielsen spectral Neugebauer （CYNSN） submodels. In the exp...Seven color separation criteria are evaluated and compared for multi-ink printer characterization, which is a union of five 3-ink and six 4-ink cellular Yule-Nielsen spectral Neugebauer （CYNSN） submodels. In the experimental stage, testing reflectances from printing samples and Munsell color samples are employed. The results show that the prediction and actual accuracy of all the seven selection criteria are approximately the same for printing samples. As for the Munsell samples, the combE00 ＆ MI outperforms other selection criteria because it combines one color difference with two metamerism indices, which are important for the heterogeneous samples during prediction.展开更多
A spectral-based 8-ink characterization model is developed to accurately predict the recipe for a multi-ink printer. The 8-ink color separation method is a union of five 3-ink and six 4-ink combinations based on the c...A spectral-based 8-ink characterization model is developed to accurately predict the recipe for a multi-ink printer. The 8-ink color separation method is a union of five 3-ink and six 4-ink combinations based on the cellular Yule-Nielsen spectral Neugebauer model with a recipe selection strategy. The performance levels of the forward and backward models are evaluated for individual ink combinations using printed testing samples. Furthermore, the spectral-based method performs better compared with the XYZ-based approach. On the basis of the backward model performance, a novel fast recipe selection strategy is proposed and estimated.展开更多
A camera-based model is established to predict the total difference for samples of metallic panels with effect coatings under directional illumination, and the testing results indicate that the model can precisely pre...A camera-based model is established to predict the total difference for samples of metallic panels with effect coatings under directional illumination, and the testing results indicate that the model can precisely predict the total difference between samples with metallic coatings with satisfactory consistency to the visual data. Due to the limited amount of testing samples, the model performance should be further developed by increasing the training and testing samples.展开更多
Pearlescent coatings become highly popular to the modern generation of color rendering materials due to their unique color effect. However, it is quite challenging to evaluate its color appearance by traditional color...Pearlescent coatings become highly popular to the modern generation of color rendering materials due to their unique color effect. However, it is quite challenging to evaluate its color appearance by traditional color measurement. A low-cost camera is a highly efficient device for multi-geometry color appearance estimation for pearlescent bottles, which has been achieved through the camera characterization, sample image capturing, and then mathematical transforming from RGB （red, green, and blue） values to color appearance attributes based on the color appearance model of CIECAM02. A tele-spectroradiometer for physical measurement together with visual assessment is applied for comparison with the camera method to evaluate the accuracy of camera predictions and discuss the applicability of CIECAM02. The experimental results indicate that the camera data have strong correlation with the physical measurement and also fit well with visual data except for a slight slope shift existing in lightness due to a divinable psychophysical magnitude variation for spatial-dependent color samples. Hence it is feasible to estimate the color appearance of pearlescent bottles using a digital camera.展开更多
Effect coatings have the unique property of large change of appearance under different viewing conditions. This results in quality control problems of related products. In this letter, samples of metallic panels with ...Effect coatings have the unique property of large change of appearance under different viewing conditions. This results in quality control problems of related products. In this letter, samples of metallic panels with effect coatings are visually assessed and measured. Based on experimental results, we propose formulae to predict precisely the total differences of effective samples in terms of variations in color, coarseness, and glint. Under diffused illumination, the total difference formula includes color difference and coarseness difference. Under directional illumination, the total difference formula includes color difference and glint difference.展开更多
Conventional printer characterisation models are generally based on the assumption that the densities of primary colours are additive. However, additivity failure frequently occurs in practice. We propose a novel grey...Conventional printer characterisation models are generally based on the assumption that the densities of primary colours are additive. However, additivity failure frequently occurs in practice. We propose a novel grey component replacement （GCR） method based on the spectral density sub-additivity equations in this letter for spectral characterisation of a 4-ink colour printer. The method effectively correct the error caused by additivity failure. Real high-quality hardcopy samples are produced as evidence of the feasibility of the proposed method and to evaluate the model performance. Finally, the GCR model for characterising colour printer with high spectral and colorimetric Drediction accuracv is established.展开更多
A psychophysical experiment is performed on two large-size liquid crystal displays under three viewing conditions to assess perceptual contrast. Based on the visual data, the performance of CIECAM02 in pre- dicting pe...A psychophysical experiment is performed on two large-size liquid crystal displays under three viewing conditions to assess perceptual contrast. Based on the visual data, the performance of CIECAM02 in pre- dicting perceptual contrast under different viewing conditions is tested and compared with other models by F-test, Results show that the perceptual contrast models in the form of Weber contrast using CIECAM02 brightness Q agreed better with the contrast perception of human visual system compared to the models using luminance, CIELAB lightness L＊, and CIECAM02 liehtness J.展开更多
文摘The cellular Yule-Nielson spectral Neugebauer （CYNSN） model to characterize a typical CMYK （i.e.,cyan,magenta,yellow,and black） 4-ink color printer is presented.By reconstructing spectral reflectance,models with high accuracy of spectral and colorimetric predictions are built.A novel cell-searching algorithm is proposed and used together with the iteration method to invert the cellular Neugebauer model efficiently.Large numbers of high quality hardcopy samples are produced to evaluate model performance and prove the feasibility of the algorithm.The spectral-based model performs better compared with the usual model based on CIE1931 XYZ tristimulus values.
文摘Seven color separation criteria are evaluated and compared for multi-ink printer characterization, which is a union of five 3-ink and six 4-ink cellular Yule-Nielsen spectral Neugebauer （CYNSN） submodels. In the experimental stage, testing reflectances from printing samples and Munsell color samples are employed. The results show that the prediction and actual accuracy of all the seven selection criteria are approximately the same for printing samples. As for the Munsell samples, the combE00 ＆ MI outperforms other selection criteria because it combines one color difference with two metamerism indices, which are important for the heterogeneous samples during prediction.
文摘A spectral-based 8-ink characterization model is developed to accurately predict the recipe for a multi-ink printer. The 8-ink color separation method is a union of five 3-ink and six 4-ink combinations based on the cellular Yule-Nielsen spectral Neugebauer model with a recipe selection strategy. The performance levels of the forward and backward models are evaluated for individual ink combinations using printed testing samples. Furthermore, the spectral-based method performs better compared with the XYZ-based approach. On the basis of the backward model performance, a novel fast recipe selection strategy is proposed and estimated.
文摘A camera-based model is established to predict the total difference for samples of metallic panels with effect coatings under directional illumination, and the testing results indicate that the model can precisely predict the total difference between samples with metallic coatings with satisfactory consistency to the visual data. Due to the limited amount of testing samples, the model performance should be further developed by increasing the training and testing samples.
文摘Pearlescent coatings become highly popular to the modern generation of color rendering materials due to their unique color effect. However, it is quite challenging to evaluate its color appearance by traditional color measurement. A low-cost camera is a highly efficient device for multi-geometry color appearance estimation for pearlescent bottles, which has been achieved through the camera characterization, sample image capturing, and then mathematical transforming from RGB （red, green, and blue） values to color appearance attributes based on the color appearance model of CIECAM02. A tele-spectroradiometer for physical measurement together with visual assessment is applied for comparison with the camera method to evaluate the accuracy of camera predictions and discuss the applicability of CIECAM02. The experimental results indicate that the camera data have strong correlation with the physical measurement and also fit well with visual data except for a slight slope shift existing in lightness due to a divinable psychophysical magnitude variation for spatial-dependent color samples. Hence it is feasible to estimate the color appearance of pearlescent bottles using a digital camera.
基金supported by the National "973" Program of China under Grant No. 2009CB724006
文摘Effect coatings have the unique property of large change of appearance under different viewing conditions. This results in quality control problems of related products. In this letter, samples of metallic panels with effect coatings are visually assessed and measured. Based on experimental results, we propose formulae to predict precisely the total differences of effective samples in terms of variations in color, coarseness, and glint. Under diffused illumination, the total difference formula includes color difference and coarseness difference. Under directional illumination, the total difference formula includes color difference and glint difference.
文摘Conventional printer characterisation models are generally based on the assumption that the densities of primary colours are additive. However, additivity failure frequently occurs in practice. We propose a novel grey component replacement （GCR） method based on the spectral density sub-additivity equations in this letter for spectral characterisation of a 4-ink colour printer. The method effectively correct the error caused by additivity failure. Real high-quality hardcopy samples are produced as evidence of the feasibility of the proposed method and to evaluate the model performance. Finally, the GCR model for characterising colour printer with high spectral and colorimetric Drediction accuracv is established.
文摘A psychophysical experiment is performed on two large-size liquid crystal displays under three viewing conditions to assess perceptual contrast. Based on the visual data, the performance of CIECAM02 in pre- dicting perceptual contrast under different viewing conditions is tested and compared with other models by F-test, Results show that the perceptual contrast models in the form of Weber contrast using CIECAM02 brightness Q agreed better with the contrast perception of human visual system compared to the models using luminance, CIELAB lightness L＊, and CIECAM02 liehtness J.
