Colorimetric Characterization of LCD Based on Wavelength Partition Spectral Model
LIU Hao-xue1, CUI Gui-hua2*, HUANG Min1, WU Bing1, XU Yan-fang1, LUO Ming3
1. School of Printing & Packaging Engineering, Beijing Institute of Graphic Communication, Beijing 102600, China 2. School of Physics & Electronic Information Engineering, Wenzhou University, Wenzhou 325035, China 3. Zhejiang University, Color and Image Technology Research Center, Hangzhou 310027, China
摘要： 为了建立液晶显示器颜色计算模型，分别对EIZO CG19, IBM 19, DELL 19和HP 19 LCD显示器进行了通道独立性和颜色叠加性的检验。通过检验单通道和双通道数字驱动值与颜色三刺激值之间的关系可以验证各通道之间的独立性，从而证明了上述显示器的显示色与三原色光谱辐亮度函数之间存在线性叠加关系。实验中发现三原色光谱辐亮度与数字驱动值的关系是波长的非线性函数，提出了一种按波长分区法计算三原色光谱辐亮度函数的方法，用RGB三原色的测量光谱拟合出各波长辐亮度值与数字驱动值之间的三次多项式关系，利用这个关系可计算得到任意数字驱动值对应的三原色光谱辐亮度曲线，然后可按颜色相加关系由三原色光谱辐亮度曲线计算出任意数字驱动值下的显示色。实验结果表明，只需要测量少量几个数字驱动值下的光谱曲线就可以准确计算出任意数字驱动值下的三原色光谱辐亮度曲线，进而计算得到任意混合色的光谱辐亮度曲线，大大减少了测量样品数量。这种计算方法所需的测量样品数量少、计算准确度高，可以满足工业应用的精度要求，能作为LCD显示器颜色特征化的一种方法。
关键词：光谱的叠加性;光谱分区颜色计算;LCD显示器;色光加色混合;颜色特征化
Abstract：To establish a colorimetrical characterization model of LCDs, an experiment with EIZO CG19, IBM 19, DELL 19 and HP 19 LCDs was designed and carried out to test the interaction between RGB channels, and then to test the spectral additive property of LCDs. The RGB digital values of single channel and two channels were given and the corresponding tristimulus values were measured, then a chart was plotted and calculations were made to test the independency of RGB channels. The results showed that the interaction between channels was reasonably weak and spectral additivity property was held well. We also found that the relations between radiations and digital values at different wavelengths varied, that is, they were the functions of wavelength. A new calculation method based on piecewise spectral model, in which the relation between radiations and digital values was fitted by a cubic polynomial in each piece of wavelength with measured spectral radiation curves, was proposed and tested. The spectral radiation curves of RGB primaries with any digital values can be found out with only a few measurements and fitted cubic polynomial in this way and then any displayed color can be turned out by the spectral additivity property of primaries at given digital values. The algorithm of this method was discussed in detail in this paper. The computations showed that the proposed method was simple and the number of measurements needed was reduced greatly while keeping a very high computation precision. This method can be used as a colorimetrical characterization model.
[1] Michael Stokes, Matthew Anderson, Srinivasan Chandrasekar, et al. A Standard Default Color Space for the Internet-sRGB. Version 1.10. http://www.w3.org/Graphics/Color/sRGB.html. [2] Berns R S. Displays，1996，16(4)：173. [3] Bastani B, Cressman B，Funt B. Col. Res. Appl.，2005，30：438. [4] Wen S, Wu R. Col. Res. Appl., 2006，31(2): 102. [5] Post D L，Calhoun C S. Col. Res. Appl.，1989，14(4)：172. [6] Kwak Y, Macdonald Lindsay W. 9th Color Imaging Conference，Arizona, 2001. 355. [7] WANG Yong, XU Hai-song(王 勇. 徐海松). Journal of Image and Graphics(中国图象图形学报)，2007, 12(3): 491. [8] Thomas Jean-Baptiste, Hardeberg Jon Y, Foucherot Irene，et al. Col. Res. Appl.，2008, 33(6): 449. [9] ISO. ISO 15076-1: 2005，Image technology colour management—Architecture, Profile Format and Data Structure—Part 1: Based on ICC. 1: 2004-10[S]. Geneva: ISO, 2005. [10] ZHANG Xian-dou，XU Hai-song(张显斗，徐海松). Acta Optica Sinica(光学学报)，2007，(9)：1719. [11] GONG Rui, XU Hai-song, ZHANG Xian-dou, et al(宫 睿, 徐海松, 张显斗, 等) Acta Optica Sinica(光学学报)，2011, 31(4): 0433001. [12] Nobuhiko Tamura, Norimichi Tsumura, Yoichi Miyake. J. Soc. Inf. Display, 2003, 11(2): 1. [13] LIU Hao-xue, ZHENG Lan, DAI Li, et al(刘浩学，郑 岚，代 黎，等). Acta Optica Sinica(光学学报)，2011, 31(12): 1233002.
