Abstract. Color conversion matrices and chromatic adaptation transforms (CATs) are of central importance when converting a scene captured by a digital camera in the camera raw space into a color image suitable for display using an output-referred color space. In this article, the nature of a typical camera raw space is investigated, including its gamut and reference white. Various color conversion strategies that are used in practice are subsequently derived and examined. The strategy used by internal image-processing engines of traditional digital cameras is shown to be based upon color rotation matrices accompanied by raw channel multipliers, in contrast to the approach used by smartphones and commercial raw converters, which is typically based upon characterization matrices accompanied by conventional CATs. Several advantages of the approach used by traditional digital cameras are discussed. The connections with the color conversion methods of the DCRaw open-source raw converter and the Adobe digital negative converter are also examined, along with the nature of the Adobe color and forward matrices.

中文翻译：

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数码相机中的颜色转换矩阵：教程

摘要。在将数码相机在相机原始空间中捕获的场景转换为适合使用输出参考颜色空间显示的彩色图像时，颜色转换矩阵和色彩适应变换 (CAT) 至关重要。在本文中，研究了典型相机原始空间的性质，包括其色域和参考白色。随后推导出并检查了在实践中使用的各种颜色转换策略。与智能手机和商业原始转换器使用的方法相反，传统数码相机的内部图像处理引擎使用的策略基于颜色旋转矩阵和原始通道乘法器，而智能手机和商业原始转换器使用的方法通常基于特征矩阵传统的 CAT。讨论了传统数码相机使用的方法的几个优点。还检查了与 DCRaw 开源原始转换器和 Adob​​e 数字负片转换器的颜色转换方法的联系，以及 Adob​​e 颜色和前向矩阵的性质。