條件等色色樣在不同標準光源下之色差範圍評估

Evaluation of Color Difference Range for Metamerism Samples under Different Standard Illuminants

列本研究之目的在於探討條件等色色樣在不同光源下可能的色差範圍大小。本研究以CIE D65光源作為模擬量測的標準光源，以色溫不同的A、D50、FL2、FL7和FL11作為比較光源，分析了在D65光源下色差合格的色樣本，在其他光源上可能的偏差程度。為此，本研究基於CIE TCS99色樣本，疊加由七個隨機控制點構成的變異光譜曲線，生成了大量條件等色的光譜反射率資料集，再將這些樣本帶入其他參考光源，評估這些色差合格的條件等色色樣，在不同光源下的色差範圍。研究結果顯示，在與等色條件相似度高的光源下，樣本在色度的偏差較小，相反則增加。TCS99個顏色的表現不一致，有的色差範圍大，有的色差範圍小。FL11光源下的色差範圍最大。使用跟D65相似度較低的FL11作為第二個條件等色的限制條件，可使色樣跨光源的不確定性大幅降低。

The purpose of this study is to investigate the range of color difference for conditional metameric samples under difference illuminants. In this study, CIE D65 was used as the standard illiminant for simulated measurements, while light sources with different color temperatures, namely A, D50, FL2, FL7, and FL11, are used for comparison. The study analyzes the deviation levels of color samples that are qualified in terms of color difference under the D65 illuminant on other illuminants. To this end, a substantial dataset of conditional metameric spectral reflectance data is generated based on the CIE TCS99 samples, by superimposing spectra curves composed of seven randomly controlled points. These samples are then assessed under different reference light sources to evaluate the range of color deviations across various light sources. The experimental results show that the deviation of the samples in chromaticity is smaller under illuminants with high similarity to the metameric conditions, and vice versa. The performance of the TCS99 colors varies inconsistently, with some having a large color difference range and some having a small color difference range. The FL11 illuminant has the largest color difference range. Utilizing FL11 as the second conditional metameric constraint, which has a lower similarity to D65 as the second conditional metamerism constraint can greatly reduce the uncertainty of color samples across illuminants.