由於具有窄波特性的新式光源(如: LED)，在使用現行的CIE演色指數對該演色能力作預測時，有許多不符合人眼評價的問題。有鑑於此，許多學者提出各種不同的演色指數預測方法。其中包括四個面向，分別為色彩忠實度、色彩偏好度、色彩辨識度與色彩調和度，不同的面向對於光源評價著重的特性也就不同。
而本研究則以色彩忠實度為主，目的為評價8種不同演色指數(CIE-Ra, CRI-CAM02UCS, CRI2012, CQS, GAI, MCRI, FCI_CIELAB, FCI_CIECAM02 )的表現。透過心理物理實驗來探討演色指數的預測值與人因評價的相關性。我們使用了兩盞Telelumen®光源系統，分別作為測試光源與參考光源使用，每一盞都有16個窄波LED可供調整，藉此調配出各種光譜能量分布。我們改變4階相關色溫(2850K/4000K/5000K/6500K)及3階(高/中/低)演色能力(CIE-Ra)調配出12種測試光源，對應的參考光源與測試光源色溫相同，並有相當高的演色能力(CIE-Ra >95)。所有光源的亮度皆固定為100 cd/m2。
我們藉由改變不同12組光源進行心理物理實驗，得到27對色票樣本的視覺色差值，平均後作為測試光源的人因評價值。再與8種演色指數預測值作相關係數分析，比較8種演色指數對於色彩忠實度的表現。結果顯示以色彩忠實度為評價目標的演色指數(CRI-CAM02UCS, CIE-Ra與CRI2012)表現最好(相關係數r = 0.98)，而CQS次之(相關係數r = 0.93)。其它的演色指數表現都不是很理想，這結果表示以色彩忠實度而言，CIE-Ra仍然是精確的演色指數。

There are many problems which do not comply with the visual evaluation when making color rendering index predictions to modern light sources (e.g. LEDs) characterized with narrow band by applying the current CIE color rendering index method. For this reason, several researchers have proposed various methods to predict the color rendering index including four aspects in color fidelity, color preferences, color discrimination and color harmony respectively. For the different characteristics of light source a different procedure will be used.

This research mainly based on color fidelity. Aim to evaluate the performance of 8 different color rendering indices (CIE-Ra, CRI-CAM02UCS, CRI2012, CQS, GAI, MCRI, FCI_CIELAB, and FCI_CIECAM02). Through psychophysical experiments to investigate the correlation between color rendering index and visual evaluation.We apply two sets of Telelumen® light source system as the test light source and the reference light source respectively. Each system has 16 narrow band LEDS that can be adjusted to produce a variety of spectral power distributions (SPD). We obtain 12 test light sources via mixing up 4 different CCTs plus color rendering property (CIE-Ra) in high, middle and low levels. Both test light source and reference light source have the same CCTs and reference light sources have much higher CIE-Ra (>95). All light sources are fixed at a luminance of 100 cd/m2.

By changing of the 12 different pairs of the light sources, we conducted the psychophysical experiment to derive the visual color differences of 27 pairs test color samples. Then we average the visual color differences of 27 pairs test color samples as visual evaluation to the test light sources. And proceed the correlation coefficient analysis of visual evaluation and 8 kinds of color rendering indices to compare the color fidelity performance. The results show that the color rendering index (CRI-CAM02UCS, CIE-Ra and CRI2012) with color fidelity as evaluating target have a significant best performance (r = 0.98) and CQS (r = 0.93) followed. The others are not satisfied. This result indicates that CIE-Ra is still an accurate color rendering index for color fidelity.

[1] E. F. Schubert, J. K. Kim, “Solid-State Light Sources Getting Smart,” Science, Vol. 308, pp. 1274-1278 (2005).
[2] P. Bodrogi, P. Csuti, F. Szabo and J. Schanda, “Why does the CIE colour rendering index fail for white RGB LED light sources, ” CIE Expert Symposium on LED Light Sources: Physical Measurement and Visual and Photobiological Assessment, Tokyo, Japan (2004).
[3] J.Schanda and G.Madár, “Colour rendering index of LED light sources,” Proceedings of the Lumen V4 Conference, 1-8, Balatonfured, Hungary (2006).
[4] N. Narendran and L. Deng, “Colour Rendering Properties of LED light sources,” Proc. SPIE, Vol. 4776, pp. 61-67 (2002).
[5] CIE2015, Technical Committees. Available at: http://www.cie.co.at/index.php/Technical+Committees, Accessed 17 June 2015.
[6] CIE 17.4-1987 International Lighting Vocabulary
[7] K. W. Houser, M. Wei, A. David, M. R. Krames, and X. S. Shen, “Review of measures for light-source color rendition and considerations for a two-measure system for characterizing color rendition,” OSA., Vol. 21, No. 8, pp. 10393-10411 (2013).
[8] M. S. Rea, and J. P. Freyssinier, “Color rendering: Beyond pride and prejudice,” Color Res. Appl., Vol. 35, No. 6, pp. 401-409 (2010).
[9] K. Smet, W. R. Ryckaert, M. R. Pointer, G. Deconinck, P. Hanselaer, “Correlation between color quality metric predictions and visual appreciation of light sources,” Opt. Exp., Vol. 19, No.9, pp. 8151-8166 (2011).
[10] Y. Ohno, “Spectral design considerations for color rendering of white LED light sources,” Opt. Engng., Vol. 44, No. 11, pp. 111302-1-9 (2005).
[11] Noboru Ohta, Alan R. Robertson, Colorimetry: fundamentals and applications, John Wiley & Sons (2006).
[12] 胡國瑞、孫沛立、徐道義、陳鴻興、黃日鋒、詹文鑫、羅梅君 合著，陳鴻興 編審，顯示色彩工程學，台北，全華圖書股份有限公司 (2009)。
[13] C. S. McCamy, “Correlated Color Temperature as an Explicit Function of Chromaticity Coordinates,” Color Res. Appl., Vol. 17, No.2, pp. 142-144 (1992).
[14] CIE Publ. No.15, “Colorimetry,” Central Bureau of the CIE, Vienna (2004).
[15] M. R. Luo, “The quality of light sources,” Society of Dyers and Colourists, Color. Technol., Vol. 127, No.2, pp. 75-87 (2011).
[16] M. D. Fairchild and L. Reniff, “Time course of chromatic adaptation for color-appearance judgments,” JOSA A, Vol. 12, No.5, pp. 824-833 (1995).
[17] N. Moroney, M. D. Fairchild, R. W.G. Hunt, C. Li, M. R. Luo, T. Newman, “The CIECAM02 Color Appearance Model,”10th Color and Image Conference, pp. 23-27 (2002).
[18] F. Szabó, P. Bodrogi, J. Schanda, “A colour harmony rendering index based on predictions of colour harmony impression,” Lighting Res. Technol., Vol. 41, No. 2, pp. 165-182 (2009).
[19] CIE Publ. No.13.3, “Method of specifying and measuring color rendering properties of light sources,” Central Bureau of the CIE, Vienna, Austria (1995).
[20] D.Wendy and Y.Ohno, “Toward an improved color rendering metric,” Proc. SPIE, Vol. 5941, pp. 59411G-1-8 (2005).
[21] W. Davis and Y. Ohno, “Color quality scale,” Opt. Engng., Vol. 49, No.3, pp. 033602-2-16 (2010).
[22] C. J. Li, M. R. Luo, B. Rigg, and R. W. G. Hunt, “CMC 2000 chromatic adaptation transform: CMCCAT2000,” Color Res. Appl., Vol 27, No. 1, pp.49-58 (2002).
[23] C. Li, M. R. Luo, C. Li, G.Cui, “The CRI-CAM02UCS Colour Rendering Index,” Color Res. Appl., Vol. 37, No.3, pp. 160–167 (2011).
[24] Y. F. Chou, M. R. Luo, J. Schanda, P. Csuti, F. Szabo, G. Sárvári, “Recent developments in colour rendering indices and their impacts in Viewing Graphic Printed Materials,” 19th Color Imaging Conference,Vol. 19, pp.61-65 (2011).
[25] M. S. Rea and J. P. Freyssinier-Nova, “Color rendering: a tale of two metrics,” Color Res. Appl., Vol. 33, No. 3, pp. 192–202 (2008).
[26] K. Hashimoto, T. Yano, M. Shimizu, and Y. Nayatani, “New method for specifying color-rendering properties of light sources based on feeling of contrast,” Color Res. Appl., Vol. 32, No. 5, pp.361–371 (2007).
[27] K. A. G. Smet, W. R. Ryckaert, M. R. Pointer, G. Deconinck, and P. Hanselaer, “Memory colours and colour quality evaluation of conventional and solid-state lamps,” Opt. Exp., Vol. 18, No. 25, pp. 26229–26244 (2010).
[28] D. B. Judd, “A flattery index for artificial illuminants,” Illum. Engng. Vol. 62, pp. 593–598 (1967).
[29] KAG Smet, J. Schanda, L. Whitehead and M. R. Luo, “CRI2012: A proposal for updating the CIE colour rendering index,” Lighting Res. Technol., Vol. 45, No.6, pp. 689-709 (2013).
[30] T.Ricchard, “Interpretation of the Correlation Coefficient: A Basic Review,” Jour. Diagn. Med. Sono. Vol. 6, No. 1, pp. 35-39 (1990).
[31] Thurstone, L. L., “A law of comparative judgment,” Psychological Review,” Vol 101, No. 2, pp. 266-270 (1994).