Structural analysis of printed mathematical expressions using LL(1) grammar

The current optical character recognition(OCR) has the high efficiency of indentification for the handwriting and the printed texts,but it hasn′t the function to analyse and recombine the mathematical expressions.A method of understanding mathematical expressions by the basic design method of programmig is proposed.Mainly discussed here are the method of locating superscripts and subscripts,the LL(1) grammar structure of mathematical expressions,and the structure analyzer.The recognition process is briefly described using neural networks.To understand the mathematical expressions in a printed scientific document,the pretreatment,character segmentation and recognition are performed,ending up with a series of characters sorted by left border.Then a structure analyzer is used to determine the location of subscripts and superscripts and the relative positions.Finally,the grammar tree produced by the structure analyzer is transfered into a LaTex document.Quite satisfactory experimental results were obtained.