Wavelet-Based Approach to Character Skeleton
Wavelet-Based Approach to Character Skeleton
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DOI：
10.1109/tip.2007.891800
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发表时间：
2007-05
影响因子：
10.6
通讯作者：
Xinge You;Y. Tang
中科院分区：
文献类型：
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作者：
Xinge You;Y. Tang
字符骨架在字符识别中起着重要的作用。一个字的笔画可以由两个区域组成，即单一区域和规则区域。笔画的交汇点属于奇异区，笔画的笔直和流畅部分属于规则区。因此，骨架化方法需要两个不同的过程来处理这两个不同区域的骨骼。所有传统的骨架化算法都是基于对称性分析技术。这些方法的主要问题如下。1)常规区域的初级骨架的计算是间接的，因此其实施复杂且成本高昂。2)提取的骨架不能准确定位在笔划的中心线上。3)奇异区域中捕获的骨架可能会被伪影和分支扭曲。针对这些问题，提出了一种基于小波变换的字符骨架提取方法。该方案包括两个主要步骤：a)在规则区域中提取主骨架；b)在奇异区域中对主骨架进行修正处理和连接。在第一步中使用了一种直接的技术，其中提出了一种新的基于小波的对称性分析来直接寻找笔划的中心线。第二步设计了一种新的平滑内插方法，对主骨架进行平滑操作，然后提出了一种内插补偿技术来链接主骨架，从而产生奇异区域中的骨架。实验结果表明，该方法不仅适用于二值图像，也适用于灰度图像，且对噪声和仿射变换具有较强的鲁棒性
Character skeleton plays a significant role in character recognition. The strokes of a character may consist of two regions, i.e., singular and regular regions. The intersections and junctions of the strokes belong to singular region, while the straight and smooth parts of the strokes are categorized to regular region. Therefore, a skeletonization method requires two different processes to treat the skeletons in theses two different regions. All traditional skeletonization algorithms are based on the symmetry analysis technique. The major problems of these methods are as follows. 1) The computation of the primary skeleton in the regular region is indirect, so that its implementation is sophisticated and costly. 2) The extracted skeleton cannot be exactly located on the central line of the stroke. 3) The captured skeleton in the singular region may be distorted by artifacts and branches. To overcome these problems, a novel scheme of extracting the skeleton of character based on wavelet transform is presented in this paper. This scheme consists of two main steps, namely: a) extraction of primary skeleton in the regular region and b) amendment processing of the primary skeletons and connection of them in the singular region. A direct technique is used in the first step, where a new wavelet-based symmetry analysis is developed for finding the central line of the stroke directly. A novel method called smooth interpolation is designed in the second step, where a smooth operation is applied to the primary skeleton, and, thereafter, the interpolation compensation technique is proposed to link the primary skeleton, so that the skeleton in the singular region can be produced. Experiments are conducted and positive results are achieved, which show that the proposed skeletonization scheme is applicable to not only binary image but also gray-level image, and the skeleton is robust against noise and affine transform