Fast and Accurate Skew Estimation Based on Distance Transform

Abstract

Document skew estimation is an important step in the process of document analysis. In this paper we discuss the properties of the distance transform of binarized documents and derive a fast and accurate method for detecting document skew. The method is based on the observation that the dominant orientation of the gradient of the distance transform accurately reflects the skew of the document. Our experiments suggest the method is robust to large variations in text properties, such as difference in script and page layout, and provides estimation accuracy of state-of-the-art skew detection methods.