We propose the first approach that can generate procedural three-dimensional (3D) hair involving braids modeled from a single-view photograph. Existing single-view image-based hair modeling methods fail to handle braided hairstyles. Our approach combines image processing, deep neural networks, as well as two-dimensional (2D) and 3D geometric algorithms. In order to train our neural network, we create a braid unit data set. Our recognition and segmentation system can successfully segment hair regions, braid and non-braid regions, using convolutional neural networks. We further process the images to obtain the locations, sizes, and orientations of the braid units. Given these braid units, we perform braid structure analysis to obtain the braid strand curves. The procedural modeling of the 3D braids is represented using 3D helical curves where the parameters are extracted from the 2D image analysis. Furthermore, we extract 2D hair strands from the non-braid region using the Gabor filter and orientation maps. Then, a 3D hair volume is generated with the hair region silhouette information. We project the 2D hair strands and braids on the 3D hair volume to obtain the 3D hair strands and 3D braids. The strands for the braid and non-braid regions are used as guides to generate dense hair strands. Dense strands are emitted from the hair root triangle mesh and follow the guide strands. With a sparse set of landmarks, the hair region of the photograph is texture mapped to the 3D hair root mesh and used to color the strands. We successfully tested our approach on photographs showing variations of braid styles and hair color.

中文翻译：

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通过编织单元识别的单视图程序编织头发建模

我们提出了第一种方法，该方法可以生成涉及从单视图照片建模的辫子的程序性三维 (3D) 头发。现有的基于单视图图像的头发建模方法无法处理编织发型。我们的方法结合了图像处理、深度神经网络以及二维 (2D) 和 3D 几何算法。为了训练我们的神经网络，我们创建了一个编织单元数据集。我们的识别和分割系统可以使用卷积神经网络成功分割头发区域、辫子和非辫子区域。我们进一步处理图像以获得编织单元的位置、大小和方向。给定这些编织单元，我们执行编织结构分析以获得编织股曲线。3D 编织物的程序建模使用 3D 螺旋曲线表示，其中参数是从 2D 图像分析中提取的。此外，我们使用 Gabor 过滤器和方向图从非编织区域中提取 2D 发束。然后，使用头发区域轮廓信息生成 3D 头发体积。我们将 2D 发束和辫子投影到 3D 头发体积上，以获得 3D 发束和 3D 辫子。编织区和非编织区的股线用作引导以生成密集的发股。密集的股线从发根三角网中发出，并遵循引导股线。通过一组稀疏的地标，照片的头发区域被纹理映射到 3D 发根网格，并用于为股线着色。