【作者】 李奋华；

【导师】 田学东；

【作者基本信息】 河北大学 ， 计算机应用技术， 2005， 硕士

【摘要】 随着网络技术的迅猛发展,信息资源的电子化成为至关重要的问题。数学公式是许多科技文献的重要组成部分,手工输入困难,自动输入技术的研究就尤为重要。现有的OCR(Optical Character Recognition)技术虽然对中英文字符和数字等符号都能获得较好的识别效果,但无法处理数学公式。其原因在于数学公式具有复杂的二维嵌套结构,并且公式符号含义具有多样性,这使得数学公式在切分和结构分析方面存在很多困难。因此,数学公式识别已经成为OCR 领域的一个研究热点。印刷数学公式识别系统主要包括三个组成部分:公式提取、公式分析与识别和公式重构。公式分析与识别作为印刷数学公式识别系统的三个组成部分之一,其准确性直接影响公式重构的质量,是整个数学公式识别系统的关键。本文对公式分析与识别部分做了较深入研究。主要从以下几个方面进行了改进: 在公式字符识别阶段,针对公式自身的特点,提出了一种基于连通域搜索的公式字符切分算法,并通过公式字符识别结果的反馈信息对粘连字符实行切分,以改善字符分割的质量,在实验中采用该切分算法取得了比较好的效果。在公式结构分析阶段,以公式字符的识别结果为基础,根据公式字符的结构布局,采用“自顶向下”和“自底向上”思想相结合的策略对数学公式进行结构分析,构建数学公式的符号关系树,实验表明,这种策略对印刷公式结构具有较好的适应性。更多还原

【Abstract】 With the rapid development of internet, it is important to convert information source from printed form to electronic form. There are lots of mathematical expressions in scientific documents, but it is difficult to enter mathematical expressions into the computer by hand, this makes the technology of OCR important to recognizing mathematical expressions in these scientific documents. Although the technology of OCR has a satisfying recognition effect for Chinese and English characters as well as digital symbols, it is not efficient very much in recognition of mathematical expressions. Because of two-dimensional features of mathematical expressions and the variety of meanings of mathematical expressions, it has great difficulty in segmentation and structural analysis of mathematical expressions. So the research for recognition of mathematical expressions becomes a hot topic in OCR area. Recognition of typeset mathematical expressions is a complex process. This process can be divided into three steps: extraction of mathematical expressions, analysis and recognition of mathematical expressions, and structure reconstruction of mathematical expressions. Analysis and recognition of mathematical expressions in this process has an important effect on structure reconstruction of mathematical expressions; it dominates the efficiency of mathematical expressions recognition, and therefore is crucial in mathematical expressions recognition system. In this paper, we do a quantitative research in analysis and recognition of mathematical expressions phase, as follows: In symbols recognition, an algorithm of symbols segmentation by connected areas which improves the accuracy of symbols segmentation is put forward, and a method of symbols segmentation based on the feedback result of symbols recognition is applied to segment the conglutination symbols in mathematical expressions successfully. In structural analysis, to the layout of mathematical symbols, we apply a method which connects the way of “Top-Down”with the way of “Bottom-Up”to analyze the structure of mathematical expressions; this is based on the result of symbols recognition. In experiments, this method has shown favorable adaptability for the structure of typeset mathematical expressions.更多还原