In this article, we present an evaluation method for the skin color distribution in the face area. Unlike previous methods that extract a specific area, our method subdivides the entire face into small regions and analyzes detailed, per‐frame textures. Our evaluation method for skin color distribution is based on facial feature points and includes segmentation that takes into account the facial skeleton and muscle orientation. The use of facial feature points enables a comparison at relatively equal positions on the face without depending on the shape or size of the individual's face. Our evaluation method is versatile, and as an application, we clarified age‐specific features and seasonal variations of facial color distribution. As a result of applying this evaluation method to the facial images of women aged 20 to 78 years, we confirmed that the lightness of the face decreased as age increased. In particular, the decrease in lightness was remarkable in the region along the cheekbone, from the temple to the center of the cheek. Furthermore, we analyzed the seasonal changes of melanin distribution in the face area. This showed that the melanin index increased particularly in the cheekbone area in the summer when the influence of ultraviolet rays became large. Our novel methodology and the data presented in this article will be useful in various fields, such as dermatology, cosmetics, and computer vision.

中文翻译：

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面部图像中皮肤颜色分布的图像评估方法的开发及其应用：面部颜色分布的老化效应和季节性变化

在本文中，我们提出了一种评估面部区域皮肤颜色分布的方法。与以前的提取特定区域的方法不同，我们的方法将整个面部细分为较小的区域并分析详细的每帧纹理。我们针对肤色分布的评估方法基于面部特征点，并且包括考虑面部骨骼和肌肉方向的细分。使用面部特征点可以在不相对于个人面部形状或大小的情况下，在面部上相对相等的位置进行比较。我们的评估方法用途广泛，并且作为一种应用程序，我们阐明了特定于年龄的特征和面部颜色分布的季节性变化。由于将这种评估方法应用于20至78岁女性的面部图像，我们确认脸部的亮度随着年龄的增长而降低。特别是，从太阳穴到脸颊中央的沿along骨区域的亮度明显降低。此外，我们分析了面部区域黑色素分布的季节性变化。这表明，当紫外线的影响变大时，夏季的the骨区域黑色素指数特别增加。我们提供的新颖方法论和本文中提供的数据将在皮肤病学，化妆品和计算机视觉等各个领域使用。我们分析了面部区域黑色素分布的季节性变化。这表明，当紫外线的影响变大时，夏季的the骨区域黑色素指数特别增加。我们提供的新颖方法论和本文中提供的数据将在皮肤病学，化妆品和计算机视觉等各个领域使用。我们分析了面部区域黑色素分布的季节性变化。这表明，当紫外线的影响变大时，夏季的the骨区域黑色素指数特别增加。我们提供的新颖方法论和本文中提供的数据将在皮肤病学，化妆品和计算机视觉等各个领域使用。