An Improved Formula Extraction Method of Printed Chinese Layouts Based on Connected Component Run-Length Feature

The mathematical formula extraction is the prerequisite of formula structure analysis, recognition and retrieval. This paper studies the formula extraction method for the printed Chinese scientific and technical document images, proposes a criterion based on connected component run-length feature to estimate formulae in text lines, and then improves the formula location method based on rules. The connected component run-length's change regularity was analyzed firstly for all symbols in a text line. Then Change-rate threshold was set to estimate whether there is formula in this line. Finally, improved formula extraction method was given. The experimental results on the samples collected from printed Chinese scientific and technical documents showed that the proposed method is effective in estimate the embedded formula, and improves the accuracy of the formula location.