Abstract: This paper proposes an extension to the existing automatic pencil drawing generation technique based on Line Integral Convolution (LIC). The original LIC pencil filter utilizes image segmentation and texture direction detection techniques for defining outlines and stroke directions, and the quality of a resulting image depends largely on the result of the white noises and the texture directions. It may fail to generate a reasonable result when the white noises and the texture directions are not consistent with the texture structure of the input image. To solve this problem, we propose in this paper to improve the existed LIC-based method. First, a more accurate and rapid graph-based image segmentation method is introduced to divide the image into different regions. Second, we present a new region-based way to produce white noises and texture directions. We also demonstrate the enhanced LIC pencil drawing is closer to the real artistic style.

Key words: pencil drawing, line integral convolution, image segmentation, Non-photo-realistic rendering

摘要： 提出了一种新的基于线性卷积积分（Line Integral Convolution）自动铅笔画生成方法。已有的基于LIC的铅笔画方法通过图像的分割和纹理方向的检测技术来获得图像的合理区域划分和各个区域笔画的方向。铅笔画的结果很大程度上依赖于纹理的方向和区域的白噪声。如果分析得到的纹理方向和白噪声和输入的图像不相一致，生成铅笔画的效果就很差。本文提出的方法改进了已有的铅笔画生成方法，首先利用基于图的图像分割方法实现快速有效的区域分割，其次提出一种新的基于区域的白噪声和纹理方向生成方法。实验表明提出的方法更接近于真实的铅笔画效果。

关键词: 铅笔画, 线积分卷积, 图像分割, 非真实感绘制