ABSTRACT Recent studies revealed the failure of typical blue-pumped white light emitting diodes (LEDs) in rendering the white appearance of surface colors, which was caused by the lack of ultraviolet (UV)/violet radiation to excite the fluorescent whitening agents (FWAs). The effect of such a failure on image color appearance has not been previously investigated, though white surfaces are important in image white balance. In this study, two 6500 K sources—one containing a normal level of UV/violet radiation to simulate CIE standard D65 and the other containing a low level of UV/violet radiation to simulate typical blue-pumped white LEDs—were created to illuminate a Macbeth ColorChecker and three whiteness standards containing different amounts of FWAs. The scene was captured and white balanced using nine different algorithms. Though the two sources caused small color differences to the ColorChecker, both physically (ΔE*ab = 1.44) and in the unbalanced images (ΔE*ab = 2.53), the source with a low level of UV/violet radiation caused noticeable color shifts to the ColorChecker in the white-balanced images regardless of the algorithms. Furthermore, the chromaticities of the three whiteness standards were all shifted toward the origin in the a*–b* plane under the source with a low level of UV/violet radiation in the white-balanced images regardless of the algorithms, making them appear more similar to each other. Overall, the findings suggested the great impact of typical blue-pumped white LEDs on image color appearance.

中文翻译：

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白平衡图像的 LED 照明和颜色外观

摘要 最近的研究表明，典型的蓝色泵浦白光发光二极管 (LED) 无法呈现表面颜色的白色外观，这是由于缺乏紫外线 (UV)/紫光辐射来激发荧光增白剂 (FWA) . 尽管白色表面在图像白平衡中很重要，但这种故障对图像颜色外观的影响之前尚未研究过。在这项研究中，创建了两个 6500 K 光源——一个包含正常水平的紫外线/紫光辐射以模拟 CIE 标准 D65，另一个包含低水平的紫外线/紫光辐射以模拟典型的蓝色泵浦白光 LED——用于照亮一个Macbeth ColorChecker 和包含不同数量 FWA 的三个白度标准。使用九种不同的算法捕获场景并进行白平衡。尽管这两个来源对 ColorChecker 造成了很小的色差，无论是物理上的 (ΔE*ab = 1.44) 还是不平衡的图像 (ΔE*ab = 2.53)，具有低水平紫外线/紫罗兰色辐射的来源都会导致显着的颜色偏移到无论算法如何，白平衡图像中的 ColorChecker。此外，无论算法如何，三种白度标准的色度都向光源下方 a*–b* 平面的原点偏移，白平衡图像中的紫外线/紫光辐射水平较低，使它们看起来更彼此相似。总的来说，研究结果表明典型的蓝色泵浦白光 LED 对图像颜色外观的影响很大。无论算法如何，具有低水平紫外线/紫光辐射的光源都会导致白平衡图像中 ColorChecker 的明显颜色偏移。此外，无论算法如何，三种白度标准的色度都向光源下方 a*–b* 平面的原点偏移，白平衡图像中的紫外线/紫光辐射水平较低，使它们看起来更彼此相似。总的来说，研究结果表明典型的蓝色泵浦白光 LED 对图像颜色外观的影响很大。无论算法如何，具有低水平紫外线/紫光辐射的光源都会导致白平衡图像中 ColorChecker 的明显颜色偏移。此外，无论算法如何，三种白度标准的色度都向光源下方 a*–b* 平面的原点偏移，白平衡图像中的紫外线/紫光辐射水平较低，使它们看起来更彼此相似。总的来说，研究结果表明典型的蓝色泵浦白光 LED 对图像颜色外观的影响很大。无论算法如何，三种白度标准的色度都向光源下方 a*–b* 平面的原点偏移，白平衡图像中的紫外线/紫光辐射水平较低，使它们看起来更类似于彼此。总的来说，研究结果表明典型的蓝色泵浦白光 LED 对图像颜色外观的影响很大。无论算法如何，三种白度标准的色度都向光源下方 a*–b* 平面的原点偏移，白平衡图像中的紫外线/紫光辐射水平较低，使它们看起来更类似于彼此。总的来说，研究结果表明典型的蓝色泵浦白光 LED 对图像颜色外观的影响很大。