Abstract: A method of structural analysis of mathematical expressions which connects the method of top-down with the way of bottom-up is put forward according to the issue of the printed mathematical expression recognition. Specific structures with root expressions, matrix expressions, superscript or subscript expressions are analyzed in a bottom-up way. Structures which have horizontal or vertical relations are analyzed using up-bottom way. This procedure is applied first to the whole region of the expression and then it is applied to each divided sub-expression region, recursively. The structure of a recognized expression is represented by a tree structure. Experiment results prove that this strategy gets higher accuracy for the structural analysis of mathematical expressions.

Key words: structural analysis, mathematical expressions, top-down, bottom-up

摘要： 针对印刷体数学公式中的结构分析，提出将“自下而上”和“自上而下”相结合的策略。自上而下是针对特殊结构的分析，特殊结构包括根号、矩阵、上下标等。自上而下是对公式整体结构的分析，并且用递归的方式对各个子表达式采用同样的分析方法。结构分析成功后，用树形结构表示整个公式的二维空间布局。实验结果表明，此种分析策略有效地提高了印刷体数学公式的结构分析成功率。

关键词: 结构分析, 数学公式, 自上而下, 自下而上