中文摘要：

马赛克图像是一种非真实感的渲染效果,主要通过组合不同形状、颜色的嵌片合成目标图像.基于测地距离度量下的Voronoi图结构,提出一种保特征的自适应马赛克图像生成方法.首先利用特征算子自动提取出源图像中的特征线,并根据这些特征线定义测地度量,从而保证在测地度量下生成的Voronoi图的边和图像特征边重合;然后通过距离变换计算每个像素到图像特征线的最近距离,并利用该距离场定义马赛克图像的密度函数;最后结合重心Voronoi图理论,采用Lloyd迭代算法优化嵌片的形状,得到最终的马赛克图像.实验结果表明,该方法得到的马赛克效果图有效地保持了源图像特征,疏密程度自适应、连续过渡,嵌片形状规则、排列整齐.

英文摘要：

Mosaic is a non-photorealistic rendering method, which synthesizes a large image by packing a collection of small colored tiles. This paper presents a novel feature-preserving method for mosaic image generation, which is based on Voronoi diagram under a non-Euclidean metric. Each Voronoi cell is taken as a tile in the mosaic image. The feature edges are first extracted from the input image automatically. Then a metric matrix is defined such that the edges of the Voronoi diagram under the new metric align with the feature edges. The sizes of the Voronoi cells are controlled by a density function derived from a distance transformation. Finally, the shapes of the Voronoi cells are further optimized by Lloyd＇s method. Experimental results show that, our algorithm keeps the features of the input image faithfully. The tiles in the generated mosaic image are well shaped and arranged, and vary in size according to the density function.