Using Scale-Space Anisotropic Smoothing for Text Line Extraction in Historical Documents

Text line extraction is vital pre-requisite for various document processing tasks. This paper presents a novel approach for text line extraction which is based on Gaussian scale space and dedicated binarization that utilize the inherent structure of smoothed text document images. It enhances the text lines in the image using multi-scale anisotropic second derivative of Gaussian filter bank at the average height of the text line. It then applies a binarization, which is based on component-tree and is tailored towards line extraction. The final stage of the algorithm is based on an energy minimization framework for removing spurious text line and assigning connected components to lines. We have tested our approach on various datasets written in different languages at range of image quality and received high detection rates, which outperform state-of-the-art algorithms. Our MATLAB code is publicly available. (http://www.cs.bgu.ac.il/similar to rafico/LineExtraction.zip)