Results of the ASTM field test of tristimulus weighting functions

In 1993, the American Society for Testing and Materials carried out a field test of newly calculated tristimulus weighting factors. These weighting factors had been calculated by a method proposed by Venable. the test also included a method of correction for bandpass dependence put forth by Stearns. the purpose of the trial was to assess the possible reduction in bandpass dependence introduced by each of these sets of weights. A large number of sets of spectral data were gathered from the cooperators in the field test. Results of integration by the various sets of tristimulus weighting factors were calculated. A total of 15 120 color differences were calculated and statistics were derived to test the probable error resulting from each method of correction. Errors attributable to bandpass dependence were on the order of a few tenths to as much as one CIELAB unit when uncorrected weight sets were used. These errors could be reduced to a few hundreths of a CIELAB unit, and in some cases to a few thousandths of a unit, by employing one correcting strategy or the other. an overall mix of strategies was ultimately chosen to minimize the bandpass dependence over the entire range of weight sets. Utilizing this mixed strategy, the median error introduced into 10-nm integration by bandpass dependence was only 0.004 CIELAB units. © 1995 John Wiley & Sons, Inc.     

Reconstruction of reflectance spectra using weighted principal component analysis

The weighted principal component analysis technique is employed for reconstruction of reflectance spectra of surface colors from the related tristimulus values. A dynamic eigenvector subspace based on applying certain weights to reflectance data of Munsell color chips has been formed for each particular sample and the color difference value between the target, and Munsell dataset is chosen as a criterion for determination of weighting factors. Implementation of this method enables one to increase the influence of samples which are closer to target on extracted principal eigenvectors and subsequently diminish the effect of those samples which benefit from higher amount of color difference. The performance of the suggested method is evaluated in spectral reflectance reconstruction of three different collections of colored samples by the use of the first three Munsell bases. The resulting spectra show considerable improvements in terms of root mean square error between the actual and reconstructed reflectance curves as well as CIELAB color difference under illuminant A in comparison to those obtained from the standard PCA method. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 360–371, 2008     

彩色摄像机彩色重现性改善的一种方法

本文在彩色摄像机实际光谱特性曲线未知,并与理论光谱特性曲线又存在偏离情况下使用线性变换原理,提出一种改善摄像机彩色重现性的方法。     

CRT显示器色度校正的单参数模型

基于Gain-Offset-Gamma(GOG)模型,提出了CRT显示器色度校正的单参数(SP)模型。此模型表达简洁,计算简单,易编程实现。实验中分别采用SP模型和GOG模型测量了CRT显示器色度特性参数,并理论预测了CRT显示器屏幕色。实验结果表明,SP模型预测的阶调复现曲线(TRCs)比GOG模型更符合测量值;对于选用的CRT显示器屏幕色样,GOG模型预测值与测量值的最大色差ΔECIE94为1.57,平均色差为1.11,而SP模型的预测值与测量值的最大色差ΔECIE94为1.06,平均色差为0.618,比GOG模型预测有较小的色差。因此,SP模型将成为最简单、高精度的一种计算机控制CRT显示器颜色表述方法。     

智能化测色仪的研究

本文说明了应用彩色传感器的智能化测色仪的基本原理和构成，提出了用最小二乘法对彩色传感器的光谱响应特性进行拟合，使其与观察者在标准照明体下的光谱反应达到最佳，并利用多种数字信号处理技术克服误差和干扰，提高测试的准确度和稳定性。     

两种测色仪器的比较和评价

介绍了两类常用的色度仪器的工作原理和结构，并对其优缺点进行了比较和评价。     

纺织品沾色程度的仪器评级研究

使用ＳＳＲ８９仪器评级公式对纺织品的沾色程度进行了评价，并与目测评级做了对比。论证了沾色程度仪器评级的可行性，同时指出了存在的一些问题。     

三原色油墨显色范围分析研究

通过实验方法,测量三原色油墨在不同印刷条件下的三刺激值,标定其色域范围,分析影响其显色范围的因素。对有效地选择三原色油墨和确定印刷条件,最大限度地再现原稿色调有着实际意义。     

光纤探头式测色系统

本文介绍了一种光纤探头式皮肤颜色测定系统。该系统依据反射光谱和色度学理论,并采用了微机处理系统,具有精度高、使用方便及智能化的特点。利用此系统进行皮肤病的诊断、疗效分析实验,取得了较好的效果。     

Spectral Response Based Calibration Method of Tristimulus Colorimeters

A new method is described to calibrate tristimulus colorimeters for high accuracy color measurements. Instead of traditional lamp standards, modern, high accuracy detector standards are suggested for calibration. After high accuracy absolute spectral response determination of the tristimulus receivers, color (spectral) correction and peak (amplitude) normalization can minimize uncertainties caused by imperfect realizations of the Commission Internationale de l’Eclairage (CIE) color matching functions. As a result of the corrections, stable light sources of different spectral power distributions can be measured with an accuracy dominated by the sub tenths of a percent uncertainty of novel spectral response determinations.