Finlayson Graham, Gong Han, Fisher Robert B
IEEE Trans Pattern Anal Mach Intell. 2019 Jan;41(1):20-33. doi: 10.1109/TPAMI.2017.2760833. Epub 2017 Dec 4.
Images of co-planar points in 3-dimensional space taken from different camera positions are a homography apart. Homographies are at the heart of geometric methods in computer vision and are used in geometric camera calibration, 3D reconstruction, stereo vision and image mosaicking among other tasks. In this paper we show the surprising result that homographies are the apposite tool for relating image colors of the same scene when the capture conditions-illumination color, shading and device-change. Three applications of color homographies are investigated. First, we show that color calibration is correctly formulated as a homography problem. Second, we compare the chromaticity distributions of an image of colorful objects to a database of object chromaticity distributions using homography matching. In the color transfer problem, the colors in one image are mapped so that the resulting image color style matches that of a target image. We show that natural image color transfer can be re-interpreted as a color homography mapping. Experiments demonstrate that solving the color homography problem leads to more accurate calibration, improved color-based object recognition, and we present a new direction for developing natural color transfer algorithms.
从不同相机位置拍摄的三维空间中共面的点的图像相差一个单应性矩阵。单应性矩阵是计算机视觉中几何方法的核心，用于几何相机校准、三维重建、立体视觉和图像拼接等任务。在本文中，我们展示了一个惊人的结果：当捕获条件（照明颜色、阴影和设备）发生变化时，单应性矩阵是关联同一场景图像颜色的合适工具。我们研究了颜色单应性矩阵的三个应用。首先，我们表明颜色校准可以正确地表述为一个单应性问题。其次，我们使用单应性匹配将彩色物体图像的色度分布与物体色度分布数据库进行比较。在颜色迁移问题中，一幅图像中的颜色被映射，以使生成的图像颜色风格与目标图像的颜色风格相匹配。我们表明自然图像颜色迁移可以重新解释为颜色单应性映射。实验表明，解决颜色单应性问题可以得到更精确的校准、改进基于颜色的物体识别，并且我们为开发自然颜色迁移算法提出了一个新方向。
