A new algorithm for skew detection in images of documents

Abstract

Very frequently the digitalisation process of documents produce images rotated of small angles in relation to the original image axis. The skew introduced makes more difficult the visualisation of images by human users. Besides that, it increases the complexity of any sort of automatic image recognition, degrades the performance of OCR tools, increases the space needed for image storage, etc. Thus, skew correction is an important part of any document processing system being a matter of concern of researchers for almost two decades now. The search for faster and good quality solutions to this problem is still on. This paper presents an efficient algorithm for skew detection and correction of images of documents including non-textual graphical elements, such as pictures and tables. The new algorithm was tested in over 10,000 images yielding satisfactory performance. Keywords: Document Image Analysis, Skew detection, Rotated Images. © Springer-Verlag 2004.